Summary:
This is part of an alternative approach to https://github.com/facebook/rocksdb/issues/8316.
Unlike that approach, this one relies on key-values getting processed one by one
during compaction, and does not involve persistence.
Specifically, the patch adds a class `BlobGarbageMeter` that can track the number
and total size of blobs in a (sub)compaction's input and output on a per-blob file
basis. This information can then be used to compute the amount of additional
garbage generated by the compaction for any given blob file by subtracting the
"outflow" from the "inflow."
Note: this patch only adds `BlobGarbageMeter` and associated unit tests. I plan to
hook up this class to the input and output of `CompactionIterator` in a subsequent PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8426
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D29242250
Pulled By: ltamasi
fbshipit-source-id: 597e50ad556540e413a50e804ba15bc044d809bb
Summary:
Tracing the MultiGet information including timestamp, keys, and CF_IDs to the trace file for analyzing and replay.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8421
Test Plan: make check, add test to trace_analyzer_test
Reviewed By: anand1976
Differential Revision: D29221195
Pulled By: zhichao-cao
fbshipit-source-id: 30c677d6c39ab31ef4bbdf7e0d1fa1fd79f295ff
Summary:
**Summary**:
2 new statistics counters are added to RocksDB: `MEMTABLE_PAYLOAD_BYTES_AT_FLUSH` and `MEMTABLE_GARBAGE_BYTES_AT_FLUSH`. The former tracks how many raw bytes of useful data are present on the memtable at flush time, whereas the latter is tracks how many of these raw bytes are considered garbage, meaning that they ended up not being imported on the SSTables resulting from the flush operations.
**Unit test**: run `make db_flush_test -j$(nproc); ./db_flush_test` to run the unit test.
This executable includes 3 tests, that test support and correct stat calculations for workloads with inserts, deletes, and DeleteRanges. The parameters are set such that the workloads are performed on a single memtable, and a single SSTable is created as a result of the flush operation. The flush operation is manually called in the test file. The tests verify that the values of these 2 statistics counters introduced in this PR can be exactly predicted, showing that we have a full understanding of the underlying operations.
**Performance testing**:
`./db_bench -statistics -benchmarks=fillrandom -num=10000000` repeated 10 times.
Timing done using "date" function in a bash script.
_Results_:
Original Rocksdb fork: mean 66.6 sec, std 1.18 sec.
This feature branch: mean 67.4 sec, std 1.35 sec.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8411
Reviewed By: akankshamahajan15
Differential Revision: D29150629
Pulled By: bjlemaire
fbshipit-source-id: 7b3c2e86d50c6aa34fa50fd134282eacb543a5b1
Summary:
This PR prepopulates warm/hot data blocks which are already in memory
into block cache at the time of flush. On a flush, the data block that is
in memory (in memtables) get flushed to the device. If using Direct IO,
additional IO is incurred to read this data back into memory again, which
is avoided by enabling newly added option.
Right now, this is enabled only for flush for data blocks. We plan to
expand this option to cover compactions in the future and for other types
of blocks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8242
Test Plan: Add new unit test
Reviewed By: anand1976
Differential Revision: D28521703
Pulled By: akankshamahajan15
fbshipit-source-id: 7219d6958821cedce689a219c3963a6f1a9d5f05
Summary:
RocksDB logs a warning if WAL truncation on DB open fails. Its possible that on some file systems, truncation is not required and they would return ```Status::NotSupported()``` for ```ReopenWritableFile```. Don't log a warning in such cases.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8414
Reviewed By: akankshamahajan15
Differential Revision: D29181738
Pulled By: anand1976
fbshipit-source-id: 6e01e9117e1e4c1d67daa4dcee7fa59d06e057a7
Summary:
This is the next part of the ImmutableOptions cleanup. After changing the use of ImmutableCFOptions to ImmutableOptions, there were places in the code that had did something like "ImmutableOptions* immutable_cf_options", where "cf" referred to the "old" type.
This change simply renames the variables to match the current type. No new functionality is introduced.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8409
Reviewed By: pdillinger
Differential Revision: D29166248
Pulled By: mrambacher
fbshipit-source-id: 96de97f8e743f5c5160f02246e3ed8269556dc6f
Summary:
This reverts commit 9167ece586.
It was found to reliably trip a compaction picking conflict assertion in a MyRocks unit test. We don't understand why yet so reverting in the meantime.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8410
Test Plan: `make check -j48`
Reviewed By: jay-zhuang
Differential Revision: D29150300
Pulled By: ajkr
fbshipit-source-id: 2de8664f355d6da015e84e5fec2e3f90f49741c8
Summary:
- Added CreateFromString method to Env and FilesSystem to replace LoadEnv/Load. This method/signature is a precursor to making these classes extend Customizable.
- Added CreateFromSystem to Env. This method standardizes creating an Env from the environment variables. Previously, some places would check TEST_ENV_URI and others would also check TEST_FS_URI. Now the code is more command/standardized.
- Added CreateFromFlags to Env. These method allows Env to be create from string options (such as GFLAGS options) in a more standard way.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8174
Reviewed By: zhichao-cao
Differential Revision: D28999603
Pulled By: mrambacher
fbshipit-source-id: 88e6911e7e91f908458a7fe10a20e93ecbc275fb
Summary:
(1)Make CompactionService derived from Customizable by defining two extra functions that are needed, as described in customizable.h comment section
(2)Revise the MyTestCompactionService class in compaction_service_test.cc to satisfy the class inheritance requirement
(3)Specify namespace of ToString() in compaction_service_test.cc to avoid function collision with CompactionService's ancestor classes
Test did:
make -j24 compaction_service_test
./compaction_service_test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8395
Reviewed By: jay-zhuang
Differential Revision: D29076068
Pulled By: hx235
fbshipit-source-id: c130100fa466939b3137e917f5fdc4b2ae8e37d4
Summary:
If the block Cache is full with strict_capacity_limit=false,
then our CacheEntryStatsCollector could be immediately evicted on
release, so iterating through column families with shared block cache
could trigger re-scan for each CF. This change fixes that problem by
pinning the CacheEntryStatsCollector from InternalStats so that it's not
evicted.
I had originally thought that this object could participate in LRU like
everything else, but even though a re-load+re-scan only touches memory,
it can be orders of magnitude more expensive than other cache misses.
One service in Facebook has scans that take ~20s over 100GB block cache
that is mostly 4KB entries. (The up-side of this bug and https://github.com/facebook/rocksdb/issues/8369 is that
we had a natural experiment on the effect on some service metrics even
with block cache scans running continuously in the background--a kind
of worst case scenario. Metrics like latency were not affected enough
to trigger warnings.)
Other smaller fixes:
20s is already a sizable portion of 600s stats dump period, or 180s
default max age to force re-scan, so added logic to ensure that (for
each block cache) we don't spend more than 0.2% of our background thread
time scanning it. Nevertheless, "foreground" requests for cache entry
stats (calls to `db->GetMapProperty(DB::Properties::kBlockCacheEntryStats)`)
are permitted to consume more CPU.
Renamed field to cache_entry_stats_ to match code style.
This change is intended for patching in 6.21 release.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8385
Test Plan:
unit test expanded to cover new logic (detect regression),
some manual testing with db_bench
Reviewed By: ajkr
Differential Revision: D29042759
Pulled By: pdillinger
fbshipit-source-id: 236faa902397f50038c618f50fbc8cf3f277308c
Summary:
Recalculate the total size after generate new sst files.
New generated files might have different size as the previous time which
could cause the test failed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8396
Test Plan:
```
gtest-parallel ./db_compaction_test
--gtest_filter=DBCompactionTest.ManualCompactionMax -r 1000 -w 100
```
Reviewed By: akankshamahajan15
Differential Revision: D29083299
Pulled By: jay-zhuang
fbshipit-source-id: 49d4bd619cefc0f9a1f452f8759ff4c2ba1b6fdb
Summary:
The subcompaction boundary picking logic does not currently guarantee
that all user keys that differ only by timestamp get processed by the same
subcompaction. This can cause issues with the `CompactionIterator` state
machine: for instance, one subcompaction that processes a subset of such KVs
might drop a tombstone based on the KVs it sees, while in reality the
tombstone might not have been eligible to be optimized out.
(See also https://github.com/facebook/rocksdb/issues/6645, which adjusted the way compaction inputs are picked for the
same reason.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8393
Test Plan: Ran `make check` and the crash test script with timestamps enabled.
Reviewed By: jay-zhuang
Differential Revision: D29071635
Pulled By: ltamasi
fbshipit-source-id: f6c72442122b4e581871e096fabe3876a9e8a5a6
Summary:
DBImpl::DumpStats is supposed to do this:
Dump DB stats to LOG
For each CF, dump CFStatsNoFileHistogram to LOG
For each CF, dump CFFileHistogram to LOG
Instead, due to a longstanding bug from 2017 (https://github.com/facebook/rocksdb/issues/2126), it would dump
CFStats, which includes both CFStatsNoFileHistogram and CFFileHistogram,
in both loops, resulting in near-duplicate output.
This fixes the bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8380
Test Plan: Manual inspection of LOG after db_bench
Reviewed By: jay-zhuang
Differential Revision: D29017535
Pulled By: pdillinger
fbshipit-source-id: 3010604c4a629a80347f129cd746ce9b0d0cbda6
Summary:
In the current logic, any IO Error with retryable flag == true will be handled by the special logic and in most cases, StartRecoverFromRetryableBGIOError will be called to do the auto resume. If the NoSpace error with retryable flag is set during WAL write, it is mapped as a hard error, which will trigger the auto recovery. During the recover process, if write continues and append to the WAL, the write process sees that bg_error is set to HardError and it calls WriteStatusCheck(), which calls SetBGError() with Status (not IOStatus). This will redirect to the regular SetBGError interface, in which recovery_error_ will be set to the corresponding error. With the recovery_error_ set, the auto resume thread created in StartRecoverFromRetryableBGIOError will keep failing as long as user keeps trying to write.
To fix this issue. All the NoSpace error (no matter retryable flag is set or not) will be redirect to the regular SetBGError, and RecoverFromNoSpace() will do the recovery job which calls SstFileManager::StartErrorRecovery().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8376
Test Plan: make check and added the new testing case
Reviewed By: anand1976
Differential Revision: D29071828
Pulled By: zhichao-cao
fbshipit-source-id: 7171d7e14cc4620fdab49b7eff7a2fe9a89942c2
Summary:
This PR add support for Merge operation in Integrated BlobDB with base values(i.e DB::Put). Merged values can be retrieved through DB::Get, DB::MultiGet, DB::GetMergeOperands and Iterator operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8292
Test Plan: Add new unit tests
Reviewed By: ltamasi
Differential Revision: D28415896
Pulled By: akankshamahajan15
fbshipit-source-id: e9b3478bef51d2f214fb88c31ed3c8d2f4a531ff
Summary:
Changed fprintf function to fputc in ApplyVersionEdit, and replaced null characters with whitespaces.
Added unit test in ldb_test.py - verifies that manifest_dump --verbose output is correct when keys and values containing null characters are inserted.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8378
Reviewed By: pdillinger
Differential Revision: D29034584
Pulled By: bjlemaire
fbshipit-source-id: 50833687a8a5f726e247c38457eadc3e6dbab862
Summary:
Currently, we either use the file system inode or a monotonically incrementing runtime ID as the block cache key prefix. However, if we use a monotonically incrementing runtime ID (in the case that the file system does not support inode id generation), in some cases, it cannot ensure uniqueness (e.g., we have secondary cache migrated from host to host). We use DbSessionID (20 bytes) + current file number (at most 10 bytes) as the new cache block key prefix when the secondary cache is enabled. So can accommodate scenarios such as transfer of cache state across hosts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8360
Test Plan: add the test to lru_cache_test
Reviewed By: pdillinger
Differential Revision: D29006215
Pulled By: zhichao-cao
fbshipit-source-id: 6cff686b38d83904667a2bd39923cd030df16814
Summary:
Logically, subcompactions process a key range [start, end); however, the way
this is currently implemented is that the `CompactionIterator` for any given
subcompaction keeps processing key-values until it actually outputs a key that
is out of range, which is then discarded. Instead of doing this, the patch
introduces a new type of internal iterator called `ClippingIterator` which wraps
another internal iterator and "clips" its range of key-values so that any KVs
returned are strictly in the [start, end) interval. This does eliminate a (minor)
inefficiency by stopping processing in subcompactions exactly at the limit;
however, the main motivation is related to BlobDB: namely, we need this to be
able to measure the amount of garbage generated by a subcompaction
precisely and prevent off-by-one errors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8327
Test Plan: `make check`
Reviewed By: siying
Differential Revision: D28761541
Pulled By: ltamasi
fbshipit-source-id: ee0e7229f04edabbc7bed5adb51771fbdc287f69
Summary:
In final polishing of https://github.com/facebook/rocksdb/issues/8297 (after most manual testing), I
broke my own caching layer by sanitizing an input parameter with
std::min(0, x) instead of std::max(0, x). I resisted unit testing the
timing part of the result caching because historically, these test
are either flaky or difficult to write, and this was not a correctness
issue. This bug is essentially unnoticeable with a small number
of column families but can explode background work with a
large number of column families.
This change fixes the logical error, removes some unnecessary related
optimization, and adds mock time/sleeps to the unit test to ensure we
can cache hit within the age limit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8369
Test Plan: added time testing logic to existing unit test
Reviewed By: ajkr
Differential Revision: D28950892
Pulled By: pdillinger
fbshipit-source-id: e79cd4ff3eec68fd0119d994f1ed468c38026c3b
Summary:
Added the ability to cancel an in-progress range compaction by storing to an atomic "canceled" variable pointed to within the CompactRangeOptions structure.
Tested via two tests added to db_tests2.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8351
Reviewed By: ajkr
Differential Revision: D28808894
Pulled By: ddevec
fbshipit-source-id: cb321361c9e23b084b188bb203f11c375a22c2dd
Summary:
This is a duplicate of https://github.com/facebook/rocksdb/issues/4948 by mzhaom to fix tests after rebase.
This change is a follow-up to https://github.com/facebook/rocksdb/issues/4927, which made this possible by allowing tombstone dropping/seqnum zeroing optimizations on the last key in the compaction. Now the `largest_seqno != 0` condition suffices to prevent snapshot release triggered compaction from entering an infinite loop.
The issues caused by the extraneous condition `level_and_file.second->num_deletions > 1` are:
- files could have `largest_seqno > 0` forever making it impossible to tell they cannot contain any covering keys
- it doesn't trigger compaction when there are many overwritten keys. Some MyRocks use case actually doesn't use Delete but instead calls Put with empty value to "delete" keys, so we'd like to be able to trigger compaction in this case too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8357
Test Plan: - make check
Reviewed By: jay-zhuang
Differential Revision: D28855340
Pulled By: ajkr
fbshipit-source-id: a261b51eecafec492499e6d01e8e43112f801798
Summary:
I noticed ```openat``` system call with ```O_WRONLY``` flag and ```sync_file_range``` and ```truncate``` on WAL file when using ```rocksdb::DB::OpenForReadOnly``` by way of ```db_bench --readonly=true --benchmarks=readseq --use_existing_db=1 --num=1 ...```
Noticed in ```strace``` after seeing the last modification time of the WAL file change after each run (with ```--readonly=true```).
I think introduced by 7d7f14480e from https://github.com/facebook/rocksdb/pull/8122
I added a test to catch the WAL file being truncated and the modification time on it changing.
I am not sure if a mock filesystem with mock clock could be used to avoid having to sleep 1.1s.
The test could also check the set of files is the same and that the sizes are also unchanged.
Before:
```
[ RUN ] DBBasicTest.ReadOnlyReopenMtimeUnchanged
db/db_basic_test.cc:182: Failure
Expected equality of these values:
file_mtime_after_readonly_reopen
Which is: 1621611136
file_mtime_before_readonly_reopen
Which is: 1621611135
file is: 000010.log
[ FAILED ] DBBasicTest.ReadOnlyReopenMtimeUnchanged (1108 ms)
```
After:
```
[ RUN ] DBBasicTest.ReadOnlyReopenMtimeUnchanged
[ OK ] DBBasicTest.ReadOnlyReopenMtimeUnchanged (1108 ms)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8313
Reviewed By: pdillinger
Differential Revision: D28656925
Pulled By: jay-zhuang
fbshipit-source-id: ea9e215cb53e7c830e76bc5fc75c45e21f12a1d6
Summary:
https://github.com/facebook/rocksdb/pull/8288 introduces a bug: SequenceIterWrapper should do next for seek key using internal key comparator rather than user comparator. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8328
Test Plan: Pass all existing tests
Reviewed By: ltamasi
Differential Revision: D28647263
fbshipit-source-id: 4081d684fd8a86d248c485ef8a1563c7af136447
Summary:
Error:
```
db/db_compaction_test.cc:5211:47: warning: The left operand of '*' is a garbage value
uint64_t total = (l1_avg_size + l2_avg_size * 10) * 10;
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8325
Test Plan: `$ make analyze`
Reviewed By: pdillinger
Differential Revision: D28620916
Pulled By: jay-zhuang
fbshipit-source-id: f6d58ab84eefbcc905cda45afb9522b0c6d230f8
Summary:
With Ribbon filter work and possible variance in actual bits
per key (or prefix; general term "entry") to achieve certain FP rates,
I've received a request to be able to track actual bits per key in
generated filters. This change adds a num_filter_entries table
property, which can be combined with filter_size to get bits per key
(entry).
This can vary from num_entries in at least these ways:
* Different versions of same key are only counted once in filters.
* With prefix filters, several user keys map to the same filter entry.
* A single filter can include both prefixes and user keys.
Note that FilterBlockBuilder::NumAdded() didn't do anything useful
except distinguish empty from non-empty.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8323
Test Plan: basic unit test included, others updated
Reviewed By: jay-zhuang
Differential Revision: D28596210
Pulled By: pdillinger
fbshipit-source-id: 529a111f3c84501e5a470bc84705e436ee68c376
Summary:
Fix a bug that for manual compaction, `max_compaction_bytes` is only
limit the SST files from input level, but not overlapped files on output
level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8269
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D28231044
Pulled By: jay-zhuang
fbshipit-source-id: 9d7d03004f30cc4b1b9819830141436907554b7c
Summary:
When a memtable is flushed, it will validate number of entries it reads, and compare the number with how many entries inserted into memtable. This serves as one sanity c\
heck against memory corruption. This change will also allow more counters to be added in the future for better validation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8288
Test Plan: Pass all existing tests
Reviewed By: ajkr
Differential Revision: D28369194
fbshipit-source-id: 7ff870380c41eab7f99eee508550dcdce32838ad
Summary:
The test want to make sure these's no compaction during `AddFile`
(between `DBImpl::AddFile:MutexLock` and `DBImpl::AddFile:MutexUnlock`)
but the mutex could be unlocked by `EnterUnbatched()`.
Move the lock start point after bumping the ingest file number.
Also fix the dead lock when ASSERT fails.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8307
Reviewed By: ajkr
Differential Revision: D28479849
Pulled By: jay-zhuang
fbshipit-source-id: b3c50f66aa5d5f59c5c27f815bfea189c4cd06cb
Summary:
This change gathers and publishes statistics about the
kinds of items in block cache. This is especially important for
profiling relative usage of cache by index vs. filter vs. data blocks.
It works by iterating over the cache during periodic stats dump
(InternalStats, stats_dump_period_sec) or on demand when
DB::Get(Map)Property(kBlockCacheEntryStats), except that for
efficiency and sharing among column families, saved data from
the last scan is used when the data is not considered too old.
The new information can be seen in info LOG, for example:
Block cache LRUCache@0x7fca62229330 capacity: 95.37 MB collections: 8 last_copies: 0 last_secs: 0.00178 secs_since: 0
Block cache entry stats(count,size,portion): DataBlock(7092,28.24 MB,29.6136%) FilterBlock(215,867.90 KB,0.888728%) FilterMetaBlock(2,5.31 KB,0.00544%) IndexBlock(217,180.11 KB,0.184432%) WriteBuffer(1,256.00 KB,0.262144%) Misc(1,0.00 KB,0%)
And also through DB::GetProperty and GetMapProperty (here using
ldb just for demonstration):
$ ./ldb --db=/dev/shm/dbbench/ get_property rocksdb.block-cache-entry-stats
rocksdb.block-cache-entry-stats.bytes.data-block: 0
rocksdb.block-cache-entry-stats.bytes.deprecated-filter-block: 0
rocksdb.block-cache-entry-stats.bytes.filter-block: 0
rocksdb.block-cache-entry-stats.bytes.filter-meta-block: 0
rocksdb.block-cache-entry-stats.bytes.index-block: 178992
rocksdb.block-cache-entry-stats.bytes.misc: 0
rocksdb.block-cache-entry-stats.bytes.other-block: 0
rocksdb.block-cache-entry-stats.bytes.write-buffer: 0
rocksdb.block-cache-entry-stats.capacity: 8388608
rocksdb.block-cache-entry-stats.count.data-block: 0
rocksdb.block-cache-entry-stats.count.deprecated-filter-block: 0
rocksdb.block-cache-entry-stats.count.filter-block: 0
rocksdb.block-cache-entry-stats.count.filter-meta-block: 0
rocksdb.block-cache-entry-stats.count.index-block: 215
rocksdb.block-cache-entry-stats.count.misc: 1
rocksdb.block-cache-entry-stats.count.other-block: 0
rocksdb.block-cache-entry-stats.count.write-buffer: 0
rocksdb.block-cache-entry-stats.id: LRUCache@0x7f3636661290
rocksdb.block-cache-entry-stats.percent.data-block: 0.000000
rocksdb.block-cache-entry-stats.percent.deprecated-filter-block: 0.000000
rocksdb.block-cache-entry-stats.percent.filter-block: 0.000000
rocksdb.block-cache-entry-stats.percent.filter-meta-block: 0.000000
rocksdb.block-cache-entry-stats.percent.index-block: 2.133751
rocksdb.block-cache-entry-stats.percent.misc: 0.000000
rocksdb.block-cache-entry-stats.percent.other-block: 0.000000
rocksdb.block-cache-entry-stats.percent.write-buffer: 0.000000
rocksdb.block-cache-entry-stats.secs_for_last_collection: 0.000052
rocksdb.block-cache-entry-stats.secs_since_last_collection: 0
Solution detail - We need some way to flag what kind of blocks each
entry belongs to, preferably without changing the Cache API.
One of the complications is that Cache is a general interface that could
have other users that don't adhere to whichever convention we decide
on for keys and values. Or we would pay for an extra field in the Handle
that would only be used for this purpose.
This change uses a back-door approach, the deleter, to indicate the
"role" of a Cache entry (in addition to the value type, implicitly).
This has the added benefit of ensuring proper code origin whenever we
recognize a particular role for a cache entry; if the entry came from
some other part of the code, it will use an unrecognized deleter, which
we simply attribute to the "Misc" role.
An internal API makes for simple instantiation and automatic
registration of Cache deleters for a given value type and "role".
Another internal API, CacheEntryStatsCollector, solves the problem of
caching the results of a scan and sharing them, to ensure scans are
neither excessive nor redundant so as not to harm Cache performance.
Because code is added to BlocklikeTraits, it is pulled out of
block_based_table_reader.cc into its own file.
This is a reformulation of https://github.com/facebook/rocksdb/issues/8276, without the type checking option
(could still be added), and with actual stat gathering.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8297
Test Plan: manual testing with db_bench, and a couple of basic unit tests
Reviewed By: ltamasi
Differential Revision: D28488721
Pulled By: pdillinger
fbshipit-source-id: 472f524a9691b5afb107934be2d41d84f2b129fb
Summary:
Some file systems (especially distributed FS) do not support reopening a file for writing. The ExternalSstFileIngestionJob calls ReopenWritableFile in order to sync the ingested file, which typically makes sense only on a local file system with a page cache (i.e Posix). So this change tries to sync the ingested file only if ReopenWritableFile doesn't return Status::NotSupported().
Tests:
Add a new unit test in external_sst_file_basic_test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8296
Reviewed By: jay-zhuang
Differential Revision: D28420865
Pulled By: anand1976
fbshipit-source-id: 380e7f5ff95324997f7a59864a9ac96ebbd0100c
Summary:
This patch does two things:
1) Introduces some aliases in order to eliminate/prevent long-winded type names
w/r/t the internal table property collectors (see e.g.
`std::vector<std::unique_ptr<IntTblPropCollectorFactory>>`).
2) Makes it possible to apply only a subrange of table property collectors during
table building by turning `TableBuilderOptions::int_tbl_prop_collector_factories`
from a pointer to a `vector` into a range (i.e. a pair of iterators).
Rationale: I plan to introduce a BlobDB related table property collector, which
should only be applied during table creation if blob storage is enabled at the moment
(which can be changed dynamically). This change will make it possible to include/
exclude the BlobDB related collector as needed without having to introduce
a second `vector` of collectors in `ColumnFamilyData` with pretty much the same
contents.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8298
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D28430910
Pulled By: ltamasi
fbshipit-source-id: a81d28f2c59495865300f43deb2257d2e6977c8e
Summary:
As a part of tiered storage, writing tempeature information to manifest is needed so that after DB recovery, RocksDB still has the tiering information, to implement some further necessary functionalities.
Also fix some issues in simulated hybrid FS.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8284
Test Plan: Add a new unit test to validate that the information is indeed written and read back.
Reviewed By: zhichao-cao
Differential Revision: D28335801
fbshipit-source-id: 56aeb2e6ea090be0200181dd968c8a7278037def
Summary:
Defined the abstract interface for a secondary cache in include/rocksdb/secondary_cache.h, and updated LRUCacheOptions to take a std::shared_ptr<SecondaryCache>. An item is initially inserted into the LRU (primary) cache. When it ages out and evicted from memory, its inserted into the secondary cache. On a LRU cache miss and successful lookup in the secondary cache, the item is promoted to the LRU cache. Only support synchronous lookup currently. The secondary cache would be used to implement a persistent (flash cache) or compressed cache.
Tests:
Results from cache_bench and db_bench don't show any regression due to these changes.
cache_bench results before and after this change -
Command
```./cache_bench -ops_per_thread=10000000 -threads=1```
Before
```Complete in 40.688 s; QPS = 245774```
```Complete in 40.486 s; QPS = 246996```
```Complete in 42.019 s; QPS = 237989```
After
```Complete in 40.672 s; QPS = 245869```
```Complete in 44.622 s; QPS = 224107```
```Complete in 42.445 s; QPS = 235599```
db_bench results before this change, and with this change + https://github.com/facebook/rocksdb/issues/8213 and https://github.com/facebook/rocksdb/issues/8191 -
Commands
```./db_bench --benchmarks="fillseq,compact" -num=30000000 -key_size=32 -value_size=256 -use_direct_io_for_flush_and_compaction=true -db=/home/anand76/nvm_cache/db -partition_index_and_filters=true```
```./db_bench -db=/home/anand76/nvm_cache/db -use_existing_db=true -benchmarks=readrandom -num=30000000 -key_size=32 -value_size=256 -use_direct_reads=true -cache_size=1073741824 -cache_numshardbits=6 -cache_index_and_filter_blocks=true -read_random_exp_range=17 -statistics -partition_index_and_filters=true -threads=16 -duration=300```
Before
```
DB path: [/home/anand76/nvm_cache/db]
readrandom : 80.702 micros/op 198104 ops/sec; 54.4 MB/s (3708999 of 3708999 found)
```
```
DB path: [/home/anand76/nvm_cache/db]
readrandom : 87.124 micros/op 183625 ops/sec; 50.4 MB/s (3439999 of 3439999 found)
```
After
```
DB path: [/home/anand76/nvm_cache/db]
readrandom : 77.653 micros/op 206025 ops/sec; 56.6 MB/s (3866999 of 3866999 found)
```
```
DB path: [/home/anand76/nvm_cache/db]
readrandom : 84.962 micros/op 188299 ops/sec; 51.7 MB/s (3535999 of 3535999 found)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8271
Reviewed By: zhichao-cao
Differential Revision: D28357511
Pulled By: anand1976
fbshipit-source-id: d1cfa236f00e649a18c53328be10a8062a4b6da2
Summary:
The functions will be used for remote compaction parameter
input and result.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8247
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D28104680
Pulled By: jay-zhuang
fbshipit-source-id: c0a5178e6277125118384278efea2acbf90aa6cb
Summary:
Adds a new Cache::ApplyToAllEntries API that we expect to use
(in follow-up PRs) for efficiently gathering block cache statistics.
Notable features vs. old ApplyToAllCacheEntries:
* Includes key and deleter (in addition to value and charge). We could
have passed in a Handle but then more virtual function calls would be
needed to get the "fields" of each entry. We expect to use the 'deleter'
to identify the origin of entries, perhaps even more.
* Heavily tuned to minimize latency impact on operating cache. It
does this by iterating over small sections of each cache shard while
cycling through the shards.
* Supports tuning roughly how many entries to operate on for each
lock acquire and release, to control the impact on the latency of other
operations without excessive lock acquire & release. The right balance
can depend on the cost of the callback. Good default seems to be
around 256.
* There should be no need to disable thread safety. (I would expect
uncontended locks to be sufficiently fast.)
I have enhanced cache_bench to validate this approach:
* Reports a histogram of ns per operation, so we can look at the
ditribution of times, not just throughput (average).
* Can add a thread for simulated "gather stats" which calls
ApplyToAllEntries at a specified interval. We also generate a histogram
of time to run ApplyToAllEntries.
To make the iteration over some entries of each shard work as cleanly as
possible, even with resize between next set of entries, I have
re-arranged which hash bits are used for sharding and which for indexing
within a shard.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8225
Test Plan:
A couple of unit tests are added, but primary validation is manual, as
the primary risk is to performance.
The primary validation is using cache_bench to ensure that neither
the minor hashing changes nor the simulated stats gathering
significantly impact QPS or latency distribution. Note that adding op
latency histogram seriously impacts the benchmark QPS, so for a
fair baseline, we need the cache_bench changes (except remove simulated
stat gathering to make it compile). In short, we don't see any
reproducible difference in ops/sec or op latency unless we are gathering
stats nearly continuously. Test uses 10GB block cache with
8KB values to be somewhat realistic in the number of items to iterate
over.
Baseline typical output:
```
Complete in 92.017 s; Rough parallel ops/sec = 869401
Thread ops/sec = 54662
Operation latency (ns):
Count: 80000000 Average: 11223.9494 StdDev: 29.61
Min: 0 Median: 7759.3973 Max: 9620500
Percentiles: P50: 7759.40 P75: 14190.73 P99: 46922.75 P99.9: 77509.84 P99.99: 217030.58
------------------------------------------------------
[ 0, 1 ] 68 0.000% 0.000%
( 2900, 4400 ] 89 0.000% 0.000%
( 4400, 6600 ] 33630240 42.038% 42.038% ########
( 6600, 9900 ] 18129842 22.662% 64.700% #####
( 9900, 14000 ] 7877533 9.847% 74.547% ##
( 14000, 22000 ] 15193238 18.992% 93.539% ####
( 22000, 33000 ] 3037061 3.796% 97.335% #
( 33000, 50000 ] 1626316 2.033% 99.368%
( 50000, 75000 ] 421532 0.527% 99.895%
( 75000, 110000 ] 56910 0.071% 99.966%
( 110000, 170000 ] 16134 0.020% 99.986%
( 170000, 250000 ] 5166 0.006% 99.993%
( 250000, 380000 ] 3017 0.004% 99.996%
( 380000, 570000 ] 1337 0.002% 99.998%
( 570000, 860000 ] 805 0.001% 99.999%
( 860000, 1200000 ] 319 0.000% 100.000%
( 1200000, 1900000 ] 231 0.000% 100.000%
( 1900000, 2900000 ] 100 0.000% 100.000%
( 2900000, 4300000 ] 39 0.000% 100.000%
( 4300000, 6500000 ] 16 0.000% 100.000%
( 6500000, 9800000 ] 7 0.000% 100.000%
```
New, gather_stats=false. Median thread ops/sec of 5 runs:
```
Complete in 92.030 s; Rough parallel ops/sec = 869285
Thread ops/sec = 54458
Operation latency (ns):
Count: 80000000 Average: 11298.1027 StdDev: 42.18
Min: 0 Median: 7722.0822 Max: 6398720
Percentiles: P50: 7722.08 P75: 14294.68 P99: 47522.95 P99.9: 85292.16 P99.99: 228077.78
------------------------------------------------------
[ 0, 1 ] 109 0.000% 0.000%
( 2900, 4400 ] 793 0.001% 0.001%
( 4400, 6600 ] 34054563 42.568% 42.569% #########
( 6600, 9900 ] 17482646 21.853% 64.423% ####
( 9900, 14000 ] 7908180 9.885% 74.308% ##
( 14000, 22000 ] 15032072 18.790% 93.098% ####
( 22000, 33000 ] 3237834 4.047% 97.145% #
( 33000, 50000 ] 1736882 2.171% 99.316%
( 50000, 75000 ] 446851 0.559% 99.875%
( 75000, 110000 ] 68251 0.085% 99.960%
( 110000, 170000 ] 18592 0.023% 99.983%
( 170000, 250000 ] 7200 0.009% 99.992%
( 250000, 380000 ] 3334 0.004% 99.997%
( 380000, 570000 ] 1393 0.002% 99.998%
( 570000, 860000 ] 700 0.001% 99.999%
( 860000, 1200000 ] 293 0.000% 100.000%
( 1200000, 1900000 ] 196 0.000% 100.000%
( 1900000, 2900000 ] 69 0.000% 100.000%
( 2900000, 4300000 ] 32 0.000% 100.000%
( 4300000, 6500000 ] 10 0.000% 100.000%
```
New, gather_stats=true, 1 second delay between scans. Scans take about
1 second here so it's spending about 50% time scanning. Still the effect on
ops/sec and latency seems to be in the noise. Median thread ops/sec of 5 runs:
```
Complete in 91.890 s; Rough parallel ops/sec = 870608
Thread ops/sec = 54551
Operation latency (ns):
Count: 80000000 Average: 11311.2629 StdDev: 45.28
Min: 0 Median: 7686.5458 Max: 10018340
Percentiles: P50: 7686.55 P75: 14481.95 P99: 47232.60 P99.9: 79230.18 P99.99: 232998.86
------------------------------------------------------
[ 0, 1 ] 71 0.000% 0.000%
( 2900, 4400 ] 291 0.000% 0.000%
( 4400, 6600 ] 34492060 43.115% 43.116% #########
( 6600, 9900 ] 16727328 20.909% 64.025% ####
( 9900, 14000 ] 7845828 9.807% 73.832% ##
( 14000, 22000 ] 15510654 19.388% 93.220% ####
( 22000, 33000 ] 3216533 4.021% 97.241% #
( 33000, 50000 ] 1680859 2.101% 99.342%
( 50000, 75000 ] 439059 0.549% 99.891%
( 75000, 110000 ] 60540 0.076% 99.967%
( 110000, 170000 ] 14649 0.018% 99.985%
( 170000, 250000 ] 5242 0.007% 99.991%
( 250000, 380000 ] 3260 0.004% 99.995%
( 380000, 570000 ] 1599 0.002% 99.997%
( 570000, 860000 ] 1043 0.001% 99.999%
( 860000, 1200000 ] 471 0.001% 99.999%
( 1200000, 1900000 ] 275 0.000% 100.000%
( 1900000, 2900000 ] 143 0.000% 100.000%
( 2900000, 4300000 ] 60 0.000% 100.000%
( 4300000, 6500000 ] 27 0.000% 100.000%
( 6500000, 9800000 ] 7 0.000% 100.000%
( 9800000, 14000000 ] 1 0.000% 100.000%
Gather stats latency (us):
Count: 46 Average: 980387.5870 StdDev: 60911.18
Min: 879155 Median: 1033777.7778 Max: 1261431
Percentiles: P50: 1033777.78 P75: 1120666.67 P99: 1261431.00 P99.9: 1261431.00 P99.99: 1261431.00
------------------------------------------------------
( 860000, 1200000 ] 45 97.826% 97.826% ####################
( 1200000, 1900000 ] 1 2.174% 100.000%
Most recent cache entry stats:
Number of entries: 1295133
Total charge: 9.88 GB
Average key size: 23.4982
Average charge: 8.00 KB
Unique deleters: 3
```
Reviewed By: mrambacher
Differential Revision: D28295742
Pulled By: pdillinger
fbshipit-source-id: bbc4a552f91ba0fe10e5cc025c42cef5a81f2b95
Summary:
This change enables a couple of things:
- Different ConfigOptions can have different registry/factory associated with it, thereby allowing things like a "Test" ConfigOptions versus a "Production"
- The ObjectRegistry is created fewer times and can be re-used
The ConfigOptions can also be initialized/constructed from a DBOptions, in which case it will grab some of its settings (Env, Logger) from the DBOptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8166
Reviewed By: zhichao-cao
Differential Revision: D27657952
Pulled By: mrambacher
fbshipit-source-id: ae1d6200bb7ab127405cdeefaba43c7fe694dfdd
Summary:
The WBWI has two differing modes of operation dependent on the value
of the constructor parameter `overwrite_key`.
Currently, regardless of the parameter, neither mode performs as
expected when using Merge. This PR remedies this by correctly invoking
the appropriate Merge Operator before returning results from the WBWI.
Examples of issues that exist which are solved by this PR:
## Example 1 with `overwrite_key=false`
Currently, from an empty database, the following sequence:
```
Put('k1', 'v1')
Merge('k1', 'v2')
Get('k1')
```
Incorrectly yields `v2`, that is to say that the Merge behaves like a Put.
## Example 2 with o`verwrite_key=true`
Currently, from an empty database, the following sequence:
```
Put('k1', 'v1')
Merge('k1', 'v2')
Get('k1')
```
Incorrectly yields `ERROR: kMergeInProgress`.
## Example 3 with `overwrite_key=false`
Currently, with a database containing `('k1' -> 'v1')`, the following sequence:
```
Merge('k1', 'v2')
GetFromBatchAndDB('k1')
```
Incorrectly yields `v1,v2`
## Example 4 with `overwrite_key=true`
Currently, with a database containing `('k1' -> 'v1')`, the following sequence:
```
Merge('k1', 'v1')
GetFromBatchAndDB('k1')
```
Incorrectly yields `ERROR: kMergeInProgress`.
## Example 5 with `overwrite_key=false`
Currently, from an empty database, the following sequence:
```
Put('k1', 'v1')
Merge('k1', 'v2')
GetFromBatchAndDB('k1')
```
Incorrectly yields `v1,v2`
## Example 6 with `overwrite_key=true`
Currently, from an empty database, `('k1' -> 'v1')`, the following sequence:
```
Put('k1', 'v1')
Merge('k1', 'v2')
GetFromBatchAndDB('k1')
```
Incorrectly yields `ERROR: kMergeInProgress`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8135
Reviewed By: pdillinger
Differential Revision: D27657938
Pulled By: mrambacher
fbshipit-source-id: 0fbda6bbc66bedeba96a84786d90141d776297df
Summary:
From HISTORY.md release note:
- Allow `CompactionFilter`s to apply in more table file creation scenarios such as flush and recovery. For compatibility, `CompactionFilter`s by default apply during compaction. Users can customize this behavior by overriding `CompactionFilterFactory::ShouldFilterTableFileCreation()`.
- Removed unused structure `CompactionFilterContext`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8243
Test Plan: added unit tests
Reviewed By: pdillinger
Differential Revision: D28088089
Pulled By: ajkr
fbshipit-source-id: 0799be7908e3b39fea09fc3f1ab00e13ad817fae
Summary:
Larger arena block size does provide the benefit of reducing allocation overhead, however it may cause other troubles. For example, allocator is more likely not to allocate them to physical memory and trigger page fault. Weighing the risk, we cap the arena block size to 1MB. Users can always use a larger value if they want.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7907
Test Plan: Run all existing tests
Reviewed By: pdillinger
Differential Revision: D26135269
fbshipit-source-id: b7f55afd03e6ee1d8715f90fa11b6c33944e9ea8
Summary:
Refactor kill point to one single class, rather than several extern variables. The intention was to drop unflushed data before killing to simulate some job, and I tried to a pointer to fault ingestion fs to the killing class, but it ended up with harder than I thought. Perhaps we'll need to do this in another way. But I thought the refactoring itself is good so I send it out.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8241
Test Plan: make release and run crash test for a while.
Reviewed By: anand1976
Differential Revision: D28078486
fbshipit-source-id: f9182c1455f52e6851c13f88a21bade63bcec45f
Summary:
The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions. This change cleans that up by introducing an ImmutableOptions struct. Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form).
Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR. All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes.
Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262
Reviewed By: pdillinger
Differential Revision: D28226540
Pulled By: mrambacher
fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf
Summary:
Previously the shutdown process did not properly wait for all
`compaction_thread_limiter` tokens to be released before proceeding to
delete the DB's C++ objects. When this happened, we saw tests like
"DBCompactionTest.CompactionLimiter" flake with the following error:
```
virtual
rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl():
Assertion `outstanding_tasks_ == 0' failed.
```
There is a case where a token can still be alive even after the shutdown
process has waited for BG work to complete. In particular, this happens
because the shutdown process only waits for flush/compaction scheduled/unscheduled counters to all
reach zero. These counters are decremented in `BackgroundCallCompaction()`
functions. However, tokens are released in `BGWork*Compaction()` functions, which
actually wrap the `BackgroundCallCompaction()` function.
A simple sleep could repro the race condition:
```
$ diff --git a/db/db_impl/db_impl_compaction_flush.cc
b/db/db_impl/db_impl_compaction_flush.cc
index 806bc548a..ba59efa89 100644
--- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -2442,6 +2442,7 @@ void DBImpl::BGWorkCompaction(void* arg) {
static_cast<PrepickedCompaction*>(ca.prepicked_compaction);
static_cast_with_check<DBImpl>(ca.db)->BackgroundCallCompaction(
prepicked_compaction, Env::Priority::LOW);
+ sleep(1);
delete prepicked_compaction;
}
$ ./db_compaction_test --gtest_filter=DBCompactionTest.CompactionLimiter
db_compaction_test: util/concurrent_task_limiter_impl.cc:24: virtual rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl(): Assertion `outstanding_tasks_ == 0' failed.
Received signal 6 (Aborted)
#0 /usr/local/fbcode/platform007/lib/libc.so.6(gsignal+0xcf) [0x7f02673c30ff] ?? ??:0
https://github.com/facebook/rocksdb/issues/1 /usr/local/fbcode/platform007/lib/libc.so.6(abort+0x134) [0x7f02673ac934] ?? ??:0
...
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8253
Test Plan: sleeps to expose race conditions
Reviewed By: akankshamahajan15
Differential Revision: D28168064
Pulled By: ajkr
fbshipit-source-id: 9e5167c74398d323e7975980c5cc00f450631160
Summary:
Previously we saw flakes on platforms like arm on CircleCI, such as the following:
```
Note: Google Test filter = DBTest.L0L1L2AndUpHitCounter
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from DBTest
[ RUN ] DBTest.L0L1L2AndUpHitCounter
db/db_test.cc:5345: Failure
Expected: (TestGetTickerCount(options, GET_HIT_L0)) > (100), actual: 30 vs 100
[ FAILED ] DBTest.L0L1L2AndUpHitCounter (150 ms)
[----------] 1 test from DBTest (150 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (150 ms total)
[ PASSED ] 0 tests.
[ FAILED ] 1 test, listed below:
[ FAILED ] DBTest.L0L1L2AndUpHitCounter
```
The test was totally non-deterministic, e.g., flush/compaction timing would affect how many files on each level. Furthermore, it depended heavily on platform-specific details, e.g., by having a 32KB memtable, it could become full with a very different number of entries depending on the platform.
This PR rewrites the test to build a deterministic LSM with one file per level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8259
Reviewed By: mrambacher
Differential Revision: D28178100
Pulled By: ajkr
fbshipit-source-id: 0a03b26e8d23c29d8297c1bccb1b115dce33bdcd
Summary:
As the first part of the effort of having placing different files on different storage types, this change introduces several things:
(1) An experimental interface in FileSystem that specify temperature to a new file created.
(2) A test FileSystemWrapper, SimulatedHybridFileSystem, that simulates HDD for a file of "warm" temperature.
(3) A simple experimental feature ColumnFamilyOptions.bottommost_temperature. RocksDB would pass this value to FileSystem when creating any bottommost file.
(4) A db_bench parameter that applies the (2) and (3) to db_bench.
The motivation of the change is to introduce minimal changes that allow us to evolve tiered storage development.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8222
Test Plan:
./db_bench --benchmarks=fillrandom --write_buffer_size=2000000 -max_bytes_for_level_base=20000000 -level_compaction_dynamic_level_bytes --reads=100 -compaction_readahead_size=20000000 --reads=100000 -num=10000000
followed by
./db_bench --benchmarks=readrandom,stats --write_buffer_size=2000000 -max_bytes_for_level_base=20000000 -simulate_hybrid_fs_file=/tmp/warm_file_list -level_compaction_dynamic_level_bytes -compaction_readahead_size=20000000 --reads=500 --threads=16 -use_existing_db --num=10000000
and see results as expected.
Reviewed By: ajkr
Differential Revision: D28003028
fbshipit-source-id: 4724896d5205730227ba2f17c3fecb11261744ce
Summary:
Add `num_levels`, `is_bottommost`, and table file creation
`reason` to `FilterBuildingContext`, in anticipation of more powerful
Bloom-like filter support.
To support this, added `is_bottommost` and `reason` to
`TableBuilderOptions`, which allowed removing `reason` parameter from
`rocksdb::BuildTable`.
I attempted to remove `skip_filters` from `TableBuilderOptions`, because
filter construction decisions should arise from options, not one-off
parameters. I could not completely remove it because the public API for
SstFileWriter takes a `skip_filters` parameter, and translating this
into an option change would mean awkwardly replacing the table_factory
if it is BlockBasedTableFactory with new filter_policy=nullptr option.
I marked this public skip_filters option as deprecated because of this
oddity. (skip_filters on the read side probably makes sense.)
At least `skip_filters` is now largely hidden for users of
`TableBuilderOptions` and is no longer used for implementing the
optimize_filters_for_hits option. Bringing the logic for that option
closer to handling of FilterBuildingContext makes it more obvious that
hese two are using the same notion of "bottommost." (Planned:
configuration options for Bloom-like filters that generalize
`optimize_filters_for_hits`)
Recommended follow-up: Try to get away from "bottommost level" naming of
things, which is inaccurate (see
VersionStorageInfo::RangeMightExistAfterSortedRun), and move to
"bottommost run" or just "bottommost."
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8246
Test Plan:
extended an existing unit test to exercise and check various
filter building contexts. Also, existing tests for
optimize_filters_for_hits validate some of the "bottommost" handling,
which is now closely connected to FilterBuildingContext::is_bottommost
through TableBuilderOptions::is_bottommost
Reviewed By: mrambacher
Differential Revision: D28099346
Pulled By: pdillinger
fbshipit-source-id: 2c1072e29c24d4ac404c761a7b7663292372600a
Summary:
Greatly reduced the not-quite-copy-paste giant parameter lists
of rocksdb::NewTableBuilder, rocksdb::BuildTable,
BlockBasedTableBuilder::Rep ctor, and BlockBasedTableBuilder ctor.
Moved weird separate parameter `uint32_t column_family_id` of
TableFactory::NewTableBuilder into TableBuilderOptions.
Re-ordered parameters to TableBuilderOptions ctor, so that `uint64_t
target_file_size` is not randomly placed between uint64_t timestamps
(was easy to mix up).
Replaced a couple of fields of BlockBasedTableBuilder::Rep with a
FilterBuildingContext. The motivation for this change is making it
easier to pass along more data into new fields in FilterBuildingContext
(follow-up PR).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8240
Test Plan: ASAN make check
Reviewed By: mrambacher
Differential Revision: D28075891
Pulled By: pdillinger
fbshipit-source-id: fddb3dbb8260a0e8bdcbb51b877ebabf9a690d4f
Summary:
Don't call ```rocksdb_cache_disown_data()``` as it causes the memory allocated for ```shards_``` to be leaked.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8237
Reviewed By: jay-zhuang
Differential Revision: D28039061
Pulled By: anand1976
fbshipit-source-id: c3464efe2c006b93b4be87030116a12a124598c4
Summary:
Renaming ImmutableCFOptions::info_log and statistics to logger and stats. This is stage 2 in creating an ImmutableOptions class. It is necessary because the names match those in ImmutableOptions and have different types.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8227
Reviewed By: jay-zhuang
Differential Revision: D28000967
Pulled By: mrambacher
fbshipit-source-id: 3bf2aa04e8f1e8724d825b7deacf41080c14420b
Summary:
Add new C APIs to create the JemallocNodumpAllocator and set it on a Cache object.
`make test` passes with and without `DISABLE_JEMALLOC=1`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8178
Reviewed By: jay-zhuang
Differential Revision: D27944631
Pulled By: ajkr
fbshipit-source-id: 2531729aa285a8985c58f22f093c4d53029c4a7b
Summary:
This PR is a first step at attempting to clean up some of the Mutable/Immutable Options code. With this change, a DBOption and a ColumnFamilyOption can be reconstructed from their Mutable and Immutable equivalents, respectively.
readrandom tests do not show any performance degradation versus master (though both are slightly slower than the current 6.19 release).
There are still fields in the ImmutableCFOptions that are not CF options but DB options. Eventually, I would like to move those into an ImmutableOptions (= ImmutableDBOptions+ImmutableCFOptions). But that will be part of a future PR to minimize changes and disruptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8176
Reviewed By: pdillinger
Differential Revision: D27954339
Pulled By: mrambacher
fbshipit-source-id: ec6b805ba9afe6e094bffdbd76246c2d99aa9fad
Summary:
Add compaction API for secondary instance, which compact the files to a secondary DB path without installing to the LSM tree.
The API will be used to remote compaction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8171
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D27694545
Pulled By: jay-zhuang
fbshipit-source-id: 8ff3ec1bffdb2e1becee994918850c8902caf731
Summary:
In current RocksDB, in recover the information form WAL, we do the consistency check for each column family when one WAL file is corrupted and PointInTimeRecovery is set. However, it will report a false positive alert on "SST file is ahead of WALs" when one of the CF current log number is greater than the corrupted WAL number (CF contains the data beyond the corrupted WAl) due to a new column family creation during flush. In this case, a new WAL is created (it is empty) during a flush. Also, due to some reason (e.g., storage issue or crash happens before SyncCloseLog is called), the old WAL is corrupted. The new CF has no data, therefore, it does not have the consistency issue.
Fix: when checking cfd->GetLogNumber() > corrupted_wal_number also check cfd->GetLiveSstFilesSize() > 0. So the CFs with no SST file data will skip the check here.
Note potential ignored inconsistency caused due to fix: empty CF can also be caused by write+delete. In this case, after flush, there is no SST files being generated. However, this CF still have the log in the WAL. When the WAL is corrupted, the DB might be inconsistent.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8207
Test Plan: added unit test, make crash_test
Reviewed By: riversand963
Differential Revision: D27898839
Pulled By: zhichao-cao
fbshipit-source-id: 931fc2d8b92dd00b4169bf84b94e712fd688a83e
Summary:
RocksDB allows user-specified custom comparators which may not be known to `ldb`,
a built-in tool for checking/mutating the database. Therefore, column family comparator
names mismatch encountered during manifest dump should not prevent the dumping from
proceeding.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8216
Test Plan:
```
make check
```
Also manually do the following
```
KEEP_DB=1 ./db_with_timestamp_basic_test
./ldb --db=<db> manifest_dump --verbose
```
The ldb should succeed and print something like:
```
...
--------------- Column family "default" (ID 0) --------------
log number: 6
comparator: <TestComparator>, but the comparator object is not available.
...
```
Reviewed By: ltamasi
Differential Revision: D27927581
Pulled By: riversand963
fbshipit-source-id: f610b2c842187d17f575362070209ee6b74ec6d4
Summary:
Add comment to DisableManualCompaction() which was missing.
Also explictly return from DBImpl::CompactRange() to avoid memtable flush when manual compaction is disabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8186
Test Plan: Run existing unit tests.
Reviewed By: jay-zhuang
Differential Revision: D27744517
fbshipit-source-id: 449548a48905903b888dc9612bd17480f6596a71
Summary:
When WriteBufferManager is shared across DBs and column families
to maintain memory usage under a limit, OOMs have been observed when flush cannot
finish but writes continuously insert to memtables.
In order to avoid OOMs, when memory usage goes beyond buffer_limit_ and DBs tries to write,
this change will stall incoming writers until flush is completed and memory_usage
drops.
Design: Stall condition: When total memory usage exceeds WriteBufferManager::buffer_size_
(memory_usage() >= buffer_size_) WriterBufferManager::ShouldStall() returns true.
DBImpl first block incoming/future writers by calling write_thread_.BeginWriteStall()
(which adds dummy stall object to the writer's queue).
Then DB is blocked on a state State::Blocked (current write doesn't go
through). WBStallInterface object maintained by every DB instance is added to the queue of
WriteBufferManager.
If multiple DBs tries to write during this stall, they will also be
blocked when check WriteBufferManager::ShouldStall() returns true.
End Stall condition: When flush is finished and memory usage goes down, stall will end only if memory
waiting to be flushed is less than buffer_size/2. This lower limit will give time for flush
to complete and avoid continous stalling if memory usage remains close to buffer_size.
WriterBufferManager::EndWriteStall() is called,
which removes all instances from its queue and signal them to continue.
Their state is changed to State::Running and they are unblocked. DBImpl
then signal all incoming writers of that DB to continue by calling
write_thread_.EndWriteStall() (which removes dummy stall object from the
queue).
DB instance creates WBMStallInterface which is an interface to block and
signal DBs during stall.
When DB needs to be blocked or signalled by WriteBufferManager,
state_for_wbm_ state is changed accordingly (RUNNING or BLOCKED).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7898
Test Plan: Added a new test db/db_write_buffer_manager_test.cc
Reviewed By: anand1976
Differential Revision: D26093227
Pulled By: akankshamahajan15
fbshipit-source-id: 2bbd982a3fb7033f6de6153aa92a221249861aae
Summary:
Fixes https://github.com/facebook/rocksdb/issues/6245.
Adapted from https://github.com/facebook/rocksdb/issues/8201 and https://github.com/facebook/rocksdb/issues/8205.
Previously we were writing the ingested file's smallest/largest internal keys
with sequence number zero, or `kMaxSequenceNumber` in case of range
tombstone. The former (sequence number zero) is incorrect and can lead
to files being incorrectly ordered. The fix in this PR is to overwrite
boundary keys that have sequence number zero with the ingested file's assigned
sequence number.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8209
Test Plan: repro unit test
Reviewed By: riversand963
Differential Revision: D27885678
Pulled By: ajkr
fbshipit-source-id: 4a9f2c6efdfff81c3a9923e915ea88b250ee7b6a
Summary:
Unittest reports no space from time to time, which can be reproduced on a small memory machine with SHM. It's caused by large WAL files generated during the test, which is preallocated, but didn't truncate during close(). Adding the missing APIs to set preallocation.
It added arm test as nightly build, as the test runs more than 1 hour.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8204
Test Plan: test on small memory arm machine
Reviewed By: mrambacher
Differential Revision: D27873145
Pulled By: jay-zhuang
fbshipit-source-id: f797c429d6bc13cbcc673bc03fcc72adda55f506
Summary:
In a distributed environment, a file `rename()` operation can succeed on server (remote)
side, but the client can somehow return non-ok status to RocksDB. Possible reasons include
network partition, connection issue, etc. This happens in `rocksdb::SetCurrentFile()`, which
can be called in `LogAndApply() -> ProcessManifestWrites()` if RocksDB tries to switch to a
new MANIFEST. We currently always delete the new MANIFEST if an error occurs.
This is problematic in distributed world. If the server-side successfully updates the CURRENT
file via renaming, then a subsequent `DB::Open()` will try to look for the new MANIFEST and fail.
As a fix, we can track the execution result of IO operations on the new MANIFEST.
- If IO operations on the new MANIFEST fail, then we know the CURRENT must point to the original
MANIFEST. Therefore, it is safe to remove the new MANIFEST.
- If IO operations on the new MANIFEST all succeed, but somehow we end up in the clean up
code block, then we do not know whether CURRENT points to the new or old MANIFEST. (For local
POSIX-compliant FS, it should still point to old MANIFEST, but it does not matter if we keep the
new MANIFEST.) Therefore, we keep the new MANIFEST.
- Any future `LogAndApply()` will switch to a new MANIFEST and update CURRENT.
- If process reopens the db immediately after the failure, then the CURRENT file can point
to either the new MANIFEST or the old one, both of which exist. Therefore, recovery can
succeed and ignore the other.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8192
Test Plan: make check
Reviewed By: zhichao-cao
Differential Revision: D27804648
Pulled By: riversand963
fbshipit-source-id: 9c16f2a5ce41bc6aadf085e48449b19ede8423e4
Summary:
Historically, the DB properties `rocksdb.cur-size-active-mem-table`,
`rocksdb.cur-size-all-mem-tables`, and `rocksdb.size-all-mem-tables` called
the method `MemTable::ApproximateMemoryUsage` for mutable memtables,
which is not safe without synchronization. This resulted in data races with
memtable inserts. The patch changes the code handling these properties
to use `MemTable::ApproximateMemoryUsageFast` instead, which returns a
cached value backed by an atomic variable. Two test cases had to be updated
for this change. `MemoryTest.MemTableAndTableReadersTotal` was fixed by
increasing the value size used so each value ends up in its own memtable,
which was the original intention (note: the test has been broken in the sense
that the test code didn't consider that memtable sizes below 64 KB get
increased to 64 KB by `SanitizeOptions`, and has been passing only by
accident). `DBTest.MemoryUsageWithMaxWriteBufferSizeToMaintain` relies on
completely up-to-date values and thus was changed to use `ApproximateMemoryUsage`
directly instead of going through the DB properties. Note: this should be safe in this case
since there's only a single thread involved.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8206
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D27866811
Pulled By: ltamasi
fbshipit-source-id: 7bd754d0565e0a65f1f7f0e78ffc093beef79394
Summary:
If `options.best_efforts_recovery == true`, RocksDB currently tolerates missing table files and recovers to the latest version without missing table files (not considering WAL). It is necessary to handle blob files as well to make the feature more complete.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8180
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D27840556
Pulled By: riversand963
fbshipit-source-id: 041685d0dc2e7779ac4f0374c07a8a327704aa5e
Summary:
Added the Blob option settings from the AdvancedColmnFamilyOptions to the C API.
There are no tests for getting/setting options in the C API currently, hence no specific test plans. Should there be a some?
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8148
Reviewed By: ltamasi
Differential Revision: D27568495
Pulled By: mrambacher
fbshipit-source-id: 3a52b784467ea2c4bc58be5f75c5d41f0a5c55d6
Summary:
Updated the test to wait until all trash files are deleted by
SSTFileManager in the background. Since deletion runs in background so
number of files deleted might not always be as expected.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8196
Reviewed By: jay-zhuang
Differential Revision: D27812273
Pulled By: akankshamahajan15
fbshipit-source-id: d3ace1db34f91254b52fa455e09844d02801f58e
Summary:
Extend the DB::GetLiveFilesChecksumInfo API to blob files.
This API is also used by the file_checksum_dump ldb command to dump checksum
of SST files which now also dumps blob files checksum.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8179
Test Plan: Add new unit test
Reviewed By: zhichao-cao
Differential Revision: D27714965
Pulled By: akankshamahajan15
fbshipit-source-id: d8b7343ea845a64c83800336d88cced7152a8c92
Summary:
As the name of `DBImpl::WriteLevel0TableForRecovery` suggests, the resulting table file
should be placed on L0. However, the argument `level` passed to `BuildTable()` is -1.
We need to correct this since the level information will be useful to determine file placement.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8187
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D27748570
Pulled By: riversand963
fbshipit-source-id: e1cd23128a8de31f14b1edc2ea92754c154e4f10
Summary:
Resolves https://github.com/facebook/rocksdb/issues/8014
- Add an assertion on `DB::Open` to ensure `db_options.max_open_files` is unlimited if FIFO Compaction is being used.
- This is to align with what the docs mention and to prevent premature data deletion.
- Update tests to work with this assertion.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8172
Test Plan:
```bash
$ make check -j$(nproc)
Generated TARGETS Summary:
- 6 libs
- 0 binarys
- 180 tests
```
Reviewed By: ajkr
Differential Revision: D27768792
Pulled By: thejchap
fbshipit-source-id: cf6350535e3a3577fec72bcba75b3c094dc7a6f3
Summary:
Current flush reason attribution is misleading or incorrect (depending on what the original intention was):
- Flush due to WAL reaching its maximum size is attributed to `kWriteBufferManager`
- Flushes due to full write buffer and write buffer manager are not distinguishable, both are attributed to `kWriteBufferFull`
This changes the first to a new flush reason `kWALFull`, and splits the second between `kWriteBufferManager` and `kWriteBufferFull`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8150
Reviewed By: zhichao-cao
Differential Revision: D27569645
Pulled By: ot
fbshipit-source-id: 7e3c8ca186a6e71976e6b8e937297eebd4b769cc
Summary:
Fixing another crash test failure in the case of
write_dbid_to_manifest=true and reading a backup as read-only DB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8164
Test Plan:
enhanced unit test for backup as read-only DB, ran
blackbox_crash_test more with elevated backup_one_in
Reviewed By: zhichao-cao
Differential Revision: D27622237
Pulled By: pdillinger
fbshipit-source-id: 680d0f99ddb465a601737f2e3f2c80efd47384fb
Summary:
A current limitation of backups is that you don't know the
exact database state of when the backup was taken. With this new
feature, you can at least inspect the backup's DB state without
restoring it by opening it as a read-only DB.
Rather than add something like OpenAsReadOnlyDB to the BackupEngine API,
which would inhibit opening stackable DB implementations read-only
(if/when their APIs support it), we instead provide a DB name and Env
that can be used to open as a read-only DB.
Possible follow-up work:
* Add a version of GetBackupInfo for a single backup.
* Let CreateNewBackup return the BackupID of the newly-created backup.
Implementation details:
Refactored ChrootFileSystem to split off new base class RemapFileSystem,
which allows more general remapping of files. We use this base class to
implement BackupEngineImpl::RemapSharedFileSystem.
To minimize API impact, I decided to just add these fields `name_for_open`
and `env_for_open` to those set by GetBackupInfo when
include_file_details=true. Creating the RemapSharedFileSystem adds a bit
to the memory consumption, perhaps unnecessarily in some cases, but this
has been mitigated by (a) only initialize the RemapSharedFileSystem
lazily when GetBackupInfo with include_file_details=true is called, and
(b) using the existing `shared_ptr<FileInfo>` objects to hold most of the
mapping data.
To enhance API safety, RemapSharedFileSystem is wrapped by new
ReadOnlyFileSystem which rejects any attempts to write. This uncovered a
couple of places in which DB::OpenForReadOnly would write to the
filesystem, so I fixed these. Added a release note because this affects
logging.
Additional minor refactoring in backupable_db.cc to support the new
functionality.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8142
Test Plan:
new test (run with ASAN and UBSAN), added to stress test and
ran it for a while with amplified backup_one_in
Reviewed By: ajkr
Differential Revision: D27535408
Pulled By: pdillinger
fbshipit-source-id: 04666d310aa0261ef6b2385c43ca793ce1dfd148
Summary:
According to https://github.com/facebook/rocksdb/issues/5907, each filter partition "should include the bloom of the prefix of the last
key in the previous partition" so that SeekForPrev() in prefix mode can return correct result.
The prefix of the last key in the previous partition does not necessarily have the same prefix
as the first key in the current partition. Regardless of the first key in current partition, the
prefix of the last key in the previous partition should be added. The existing code, however,
does not follow this. Furthermore, there is another issue: when finishing current filter partition,
`FullFilterBlockBuilder::AddPrefix()` is called for the first key in next filter partition, which effectively
overwrites `last_prefix_str_` prematurely. Consequently, when the filter block builder proceeds
to the next partition, `last_prefix_str_` will be the prefix of its first key, leaving no way of adding
the bloom of the prefix of the last key of the previous partition.
Prefix extractor is FixedLength.2.
```
[ filter part 1 ] [ filter part 2 ]
abc d
```
When SeekForPrev("abcd"), checking the filter partition will land on filter part 2 because "abcd" > "abc"
but smaller than "d".
If the filter in filter part 2 happens to return false for the test for "ab", then SeekForPrev("abcd") will build
incorrect iterator tree in non-total-order mode.
Also fix a unit test which starts to fail following this PR. `InDomain` should not fail due to assertion
error when checking on an arbitrary key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8137
Test Plan:
```
make check
```
Without this fix, the following command will fail pretty soon.
```
./db_stress --acquire_snapshot_one_in=10000 --avoid_flush_during_recovery=0 \
--avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 \
--batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=17 \
--bottommost_compression_type=disable --cache_index_and_filter_blocks=1 --cache_size=1048576 \
--checkpoint_one_in=0 --checksum_type=kxxHash64 --clear_column_family_one_in=0 \
--compact_files_one_in=1000000 --compact_range_one_in=1000000 --compaction_ttl=0 \
--compression_max_dict_buffer_bytes=0 --compression_max_dict_bytes=0 \
--compression_parallel_threads=1 --compression_type=zstd --compression_zstd_max_train_bytes=0 \
--continuous_verification_interval=0 --db=/dev/shm/rocksdb/rocksdb_crashtest_whitebox \
--db_write_buffer_size=8388608 --delpercent=5 --delrangepercent=0 --destroy_db_initially=0 --enable_blob_files=0 \
--enable_compaction_filter=0 --enable_pipelined_write=1 --file_checksum_impl=big --flush_one_in=1000000 \
--format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=1000000 --get_property_one_in=1000000 \
--get_sorted_wal_files_one_in=0 --index_block_restart_interval=4 --index_type=2 --ingest_external_file_one_in=0 \
--iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True \
--log2_keys_per_lock=10 --long_running_snapshots=1 --mark_for_compaction_one_file_in=0 \
--max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=100000000 --max_key_len=3 \
--max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=16777216 --max_write_buffer_number=3 \
--max_write_buffer_size_to_maintain=8388608 --memtablerep=skip_list --mmap_read=1 --mock_direct_io=False \
--nooverwritepercent=0 --open_files=500000 --ops_per_thread=20000000 --optimize_filters_for_memory=0 --paranoid_file_checks=1 --partition_filters=1 --partition_pinning=0 --pause_background_one_in=1000000 \
--periodic_compaction_seconds=0 --prefixpercent=5 --progress_reports=0 --read_fault_one_in=0 --read_only=0 \
--readpercent=45 --recycle_log_file_num=0 --reopen=20 --secondary_catch_up_one_in=0 \
--snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 \
--sst_file_manager_bytes_per_truncate=0 --subcompactions=2 --sync=0 --sync_fault_injection=False \
--target_file_size_base=2097152 --target_file_size_multiplier=2 --test_batches_snapshots=0 --test_cf_consistency=0 \
--top_level_index_pinning=0 --unpartitioned_pinning=1 --use_blob_db=0 --use_block_based_filter=0 \
--use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 \
--use_multiget=0 --use_ribbon_filter=0 --use_txn=0 --user_timestamp_size=8 --verify_checksum=1 \
--verify_checksum_one_in=1000000 --verify_db_one_in=100000 --write_buffer_size=4194304 \
--write_dbid_to_manifest=1 --writepercent=35
```
Reviewed By: pdillinger
Differential Revision: D27553054
Pulled By: riversand963
fbshipit-source-id: 60e391e4a2d8d98a9a3172ec5d6176b90ec3de98
Summary:
DBWALTestWithParam relies on `SstFileManager` to have the expected behavior. However, if this test shares
db directories with other DBSSTTest, then the SstFileManager may see non-empty data, thus will change its
behavior to be different from expectation, introducing flakiness.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8147
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D27553362
Pulled By: riversand963
fbshipit-source-id: a2d86343e8e2220bc553b6695ce87dd21a97ddec
Summary:
With thread/process-specific dirs. (Errors seen in FB infra.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8145
Test Plan: see in FB infra tests
Reviewed By: riversand963
Differential Revision: D27542355
Pulled By: pdillinger
fbshipit-source-id: b3c8e66f91a6a6b3a775f6fc0c3cf71e63c29ade
Summary:
Add request_id in IODebugContext which will be populated by
underlying FileSystem for IOTracing purposes. Update IOTracer to trace
request_id in the tracing records. Provided API
IODebugContext::SetRequestId which will set the request_id and enable
tracing for request_id. The API hides the implementation and underlying
file system needs to call this API directly.
Update DB::StartIOTrace API and remove redundant Env* from the
argument as its not used and DB already has Env that is passed down to
IOTracer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8045
Test Plan: Update unit test.
Differential Revision: D26899871
Pulled By: akankshamahajan15
fbshipit-source-id: 56adef52ee5af0fb3060b607c3af1ec01635fa2b
Summary:
Return early in case there are zero data blocks when
`BlockBasedTableBuilder::EnterUnbuffered()` is called. This crash can
only be triggered by applying dictionary compression to SST files that
contain only range tombstones. It cannot be triggered by a low buffer
limit alone since we only consider entering unbuffered mode after
buffering a data block causing the limit to be breached, or `Finish()`ing the file. It also cannot
be triggered by a totally empty file because those go through
`Abandon()` rather than `Finish()` so unbuffered mode is never entered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8141
Test Plan: added a unit test that repro'd the "Floating point exception"
Reviewed By: riversand963
Differential Revision: D27495640
Pulled By: ajkr
fbshipit-source-id: a463cfba476919dc5c5c380800a75a86c31ffa23
Summary:
Added `TableProperties::{fast,slow}_compression_estimated_data_size`.
These properties are present in block-based tables when
`ColumnFamilyOptions::sample_for_compression > 0` and the necessary
compression library is supported when the file is generated. They
contain estimates of what `TableProperties::data_size` would be if the
"fast"/"slow" compression library had been used instead. One
limitation is we do not record exactly which "fast" (ZSTD or Zlib)
or "slow" (LZ4 or Snappy) compression library produced the result.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8139
Test Plan:
- new unit test
- ran `db_bench` with `sample_for_compression=1`; verified the `data_size` property matches the `{slow,fast}_compression_estimated_data_size` when the same compression type is used for the output file compression and the sampled compression
Reviewed By: riversand963
Differential Revision: D27454338
Pulled By: ajkr
fbshipit-source-id: 9529293de93ddac7f03b2e149d746e9f634abac4
Summary:
Fix error_handler_fs_test failure due to statistics, it will fails due to multi-thread running and resume is different.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8136
Test Plan: make check
Reviewed By: akankshamahajan15
Differential Revision: D27448828
Pulled By: zhichao-cao
fbshipit-source-id: b94255c45e9e66e93334b5ca2e4e1bfcba23fc20
Summary:
In DBImpl::CloseHelper, we wait for bg_compaction_scheduled_
and bg_flush_scheduled_ to drop to 0. Unschedule is called prior
to cancel any unscheduled flushes/compactions. It is assumed that
anything in the high priority is a flush, and anything in the low
priority pool is a compaction. This assumption, however, is broken when
the high-pri pool is full.
As a result, bg_compaction_scheduled_ can go < 0 and bg_flush_scheduled_
will remain > 0 and DB can be in hang state.
The fix is, we decrement the `bg_{flush,compaction,bottom_compaction}_scheduled_`
inside the `Unschedule{Flush,Compaction,BottomCompaction}Callback()`s. DB
`mutex_` will make the counts atomic in `Unschedule`.
Related discussion: https://github.com/facebook/rocksdb/issues/7928
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8125
Test Plan: Added new test case which hangs without the fix.
Reviewed By: jay-zhuang
Differential Revision: D27390043
Pulled By: ajkr
fbshipit-source-id: 78a367fba9a59ac5607ad24bd1c46dc16d5ec110
Summary:
Currently, we only truncate the latest alive WAL files when the DB is opened. If the latest WAL file is empty or was flushed during Open, its not truncated since the file will be deleted later on in the Open path. However, before deletion, a new WAL file is created, and if the process crash loops between the new WAL file creation and deletion of the old WAL file, the preallocated space will keep accumulating and eventually use up all disk space. To prevent this, always truncate the latest WAL file, even if its empty or the data was flushed.
Tests:
Add unit tests to db_wal_test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8122
Reviewed By: riversand963
Differential Revision: D27366132
Pulled By: anand1976
fbshipit-source-id: f923cc03ef033ccb32b140d36c6a63a8152f0e8e
Summary:
The snapshot structure returned by rocksdb_transaction_get_snapshot is
supposed to be freed by calling rocksdb_free(), so allocate using malloc
rather than new. Fixes https://github.com/facebook/rocksdb/issues/6112
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8114
Reviewed By: akankshamahajan15
Differential Revision: D27362923
Pulled By: anand1976
fbshipit-source-id: e93a8b1ffe26dafbe22529907f72b796ae971214
Summary:
The patch adds a resource management/RAII class called `ThreadGuard`,
which can be used to ensure that the managed thread is joined when the
`ThreadGuard` is destroyed, regardless of whether it is due to the
object going out of scope, an early return, an exception etc. This is
important because if an `std::thread` object is destroyed without having
been joined (or detached) first, the process is aborted (via
`std::terminate`).
For now, `ThreadGuard` is only used in the test case
`ExternalSSTFileTest.PickedLevelBug`; however, it could come in handy
elsewhere in the codebase as well (both in test code and "real" code).
Case in point: in the `PickedLevelBug` test case, with the earlier code we
could end up in the above situation when the following assertion (which is
before the threads are joined) is triggered:
```
ASSERT_FALSE(bg_compact_started.load());
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8112
Test Plan:
```
make check
gtest-parallel --repeat=10000 ./external_sst_file_test --gtest_filter="*PickedLevelBug"
```
Reviewed By: riversand963
Differential Revision: D27343185
Pulled By: ltamasi
fbshipit-source-id: 2a8c3aa68bc78cc03ec0dbae909fb25c2cd15c69
Summary:
There is bug in the current code base introduced in https://github.com/facebook/rocksdb/issues/8049 , we still set the SST file write IO Error only case as hard error. Fix it by removing the logic.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8107
Test Plan: make check, error_handler_fs_test
Reviewed By: anand1976
Differential Revision: D27321422
Pulled By: zhichao-cao
fbshipit-source-id: c014afc1553ca66b655e3bbf9d0bf6eb417ccf94
Summary:
Previously it only applied to block-based tables generated by flush. This restriction
was undocumented and blocked a new use case. Now compression sampling
applies to all block-based tables we generate when it is enabled.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8105
Test Plan: new unit test
Reviewed By: riversand963
Differential Revision: D27317275
Pulled By: ajkr
fbshipit-source-id: cd9fcc5178d6515e8cb59c6facb5ac01893cb5b0
Summary:
`strerror()` is not thread-safe, using `strerror_r()` instead. The API could be different on the different platforms, used the code from 0deef031cb/folly/String.cpp (L457)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8087
Reviewed By: mrambacher
Differential Revision: D27267151
Pulled By: jay-zhuang
fbshipit-source-id: 4b8856d1ec069d5f239b764750682c56e5be9ddb
Summary:
**Summary:**
When doing CompactFiles on the files of multiple levels(num_level > 2) with L0 is included, the compaction would fail like this.
The reason is that in `VerifyCompactionFileConsistency` it checks the levels between the L0 and base level should be empty, but it regards the compaction triggered by `CompactFiles` as an L0 -> base level compaction wrongly.
The condition is committed several years ago, whereas it isn't correct anymore.
```c++
if (vstorage->compaction_style_ == kCompactionStyleLevel &&
c->start_level() == 0 && c->num_input_levels() > 2U)
```
So this PR just deletes the incorrect check.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8024
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D26907060
Pulled By: ajkr
fbshipit-source-id: 538cef32faf464cd422e3f8de236ea3e58880c2b
Summary:
Fix race condition in
DBSSTTest.DBWithMaxSpaceAllowedWithBlobFiles where background flush
thread updates delete_blob_file but in test thread Flush() already
completes after getting bg_error and delete_blob_file remains false.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8092
Test Plan: Ran ASAN job few times on CircleCI
Reviewed By: riversand963
Differential Revision: D27275815
Pulled By: akankshamahajan15
fbshipit-source-id: 2939ad1671403881573bbe07c71aa474c5019130
Summary:
As title. All core db implementations should stay in db_impl.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8082
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D27211442
Pulled By: riversand963
fbshipit-source-id: e0953fde75064740e899aaff7989ff033b7f5232
Summary:
Add the new Append and PositionedAppend API to env WritableFile. User is able to benefit from the write checksum handoff API when using the legacy Env classes. FileSystem already implemented the checksum handoff API.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8071
Test Plan: make check, added new unit test.
Reviewed By: anand1976
Differential Revision: D27177043
Pulled By: zhichao-cao
fbshipit-source-id: 430c8331fc81099fa6d00f4fff703b68b9e8080e
Summary:
In previous codebase, if WAL is used, all the retryable IO Error will be treated as hard error. So write is stalled. In this PR, the retryable IO error from WAL sync is separated from SST file flush io error. If WAL Sync is ok and retryable IO Error only happens during SST flush, the error is mapped to soft error. So user can continue insert to Memtable and append to WAL.
Resolve the bug that if WAL sync fails, the memtable status does not roll back due to calling PickMemtable early than calling and checking SyncClosedLog.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8049
Test Plan: added new unit test, make check
Reviewed By: anand1976
Differential Revision: D26965529
Pulled By: zhichao-cao
fbshipit-source-id: f5fecb66602212523c92ee49d7edcb6065982410
Summary:
WriteController had a number of issues:
* It could introduce a delay of 1ms even if the write rate never exceeded the
configured delayed_write_rate.
* The DB-wide delayed_write_rate could be exceeded in a number of ways
with multiple column families:
* Wiping all pending delay "debts" when another column family joins
the delay with GetDelayToken().
* Resetting last_refill_time_ to (now + sleep amount) means each
column family can write with delayed_write_rate for large writes.
* Updating bytes_left_ for a partial refill without updating
last_refill_time_ would essentially give out random bonuses,
especially to medium-sized writes.
Now the code is much simpler, with these issues fixed. See comments in
the new code and new (replacement) tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8064
Test Plan: new tests, better than old tests
Reviewed By: mrambacher
Differential Revision: D27064936
Pulled By: pdillinger
fbshipit-source-id: 497c23fe6819340b8f3d440bd634d8a2bc47323f
Summary:
Add statistics and info log for error handler: counters for bg error, bg io error, bg retryable io error, auto resume, auto resume total retry, and auto resume sucess; Histogram for auto resume retry count in each recovery call.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8050
Test Plan: make check and add test to error_handler_fs_test
Reviewed By: anand1976
Differential Revision: D26990565
Pulled By: zhichao-cao
fbshipit-source-id: 49f71e8ea4e9db8b189943976404205b56ab883f
Summary:
Extend support to track blob files in SST File manager.
This PR notifies SstFileManager whenever a new blob file is created,
via OnAddFile and an obsolete blob file deleted via OnDeleteFile
and delete file via ScheduleFileDeletion.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8037
Test Plan: Add new unit tests
Reviewed By: ltamasi
Differential Revision: D26891237
Pulled By: akankshamahajan15
fbshipit-source-id: 04c69ccfda2a73782fd5c51982dae58dd11979b6
Summary:
When timestamp is enabled, key comparison should take this into account.
In `BlockBasedTableReader::Get()`, `BlockBasedTableReader::MultiGet()`,
assume the target key is `key`, and the timestamp upper bound is `ts`.
The highest key in current block is (key, ts1), while the lowest key in next
block is (key, ts2).
If
```
ts1 > ts > ts2
```
then
```
(key, ts1) < (key, ts) < (key, ts2)
```
It can be shown that if `Compare()` is used, then we will mistakenly skip the next
block. Instead, we should use `CompareWithoutTimestamp()`.
The majority of this PR makes some existing tests in `db_with_timestamp_basic_test.cc`
parameterized so that different index types can be tested. A new unit test is
also added for more coverage.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8062
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D27057557
Pulled By: riversand963
fbshipit-source-id: c1062fa7c159ed600a1ad7e461531d52265021f1
Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes.
For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.
There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved.
Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:
6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found)
6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found)
PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found)
(Note that the times for 6.18 are prior to revert of the SystemClock).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033
Reviewed By: pdillinger
Differential Revision: D27014563
Pulled By: mrambacher
fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
Summary:
CompactionDeletionTriggerReopen was observed to be flaky recently:
https://app.circleci.com/pipelines/github/facebook/rocksdb/6030/workflows/787af4f3-b9f7-4645-8e8d-1fb0ebf05539/jobs/101451.
I went through it and the related tests and arrived at different
conclusions on what constraints we can expect on DB size. Some
constraints got looser and some got tighter. The particular constraint
that flaked got a lot looser so at least the flake linked above would have been prevented.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8036
Reviewed By: riversand963
Differential Revision: D26862566
Pulled By: ajkr
fbshipit-source-id: 3512b86b4fb41aeecae32e1c7382c03916d88d88
Summary:
`DBTest.GetLiveBlobFiles` and `ObsoleteFilesTest.BlobFiles` both modify the
current `Version` in their setup phase, implicitly assuming that no other
threads would touch the `Version` while this is happening. The periodic
stats dumper thread violates this assumption; the patch fixes this by
disabling it in the affected test cases. (Note: the data race is
harmless in the sense that it only affects test code.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8055
Test Plan:
```
COMPILE_WITH_TSAN=1 make db_test -j24
gtest-parallel --repeat=10000 ./db_test --gtest_filter="*GetLiveBlobFiles"
COMPILE_WITH_TSAN=1 make obsolete_files_test -j24
gtest-parallel --repeat=10000 ./obsolete_files_test --gtest_filter="*BlobFiles"
```
Reviewed By: riversand963
Differential Revision: D27022715
Pulled By: ltamasi
fbshipit-source-id: b6cc77ed63d8bc1cbe0603522ff1a572182fc9ab
Summary:
a trial gtest upgrade discovered some parameterized tests missing instantiation. By some miracle, they still pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8051
Test Plan: thisisthetest
Reviewed By: mrambacher
Differential Revision: D27003684
Pulled By: pdillinger
fbshipit-source-id: cde1cab1551fb282f67d462d46574bd30bd5e61f
Summary:
This PR
- adds a class `ManifestTailer` that inherits from `VersionEditHandlerPointInTime`. `ManifestTailer::Iterate()` can be called multiple times to tail the primary instance's MANIFEST and apply the changes to the secondary,
- updates the implementation of `ReactiveVersionSet::ReadAndApply` to use this class,
- removes unused code in version_set.cc,
- updates existing tests, e.g. removing deleted sync points from unit tests,
- adds a new test to address the bug in https://github.com/facebook/rocksdb/issues/7815.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7998
Test Plan:
make check
Existing and newly-added tests in version_set_test.cc and db_secondary_test.cc
Reviewed By: jay-zhuang
Differential Revision: D26926641
Pulled By: riversand963
fbshipit-source-id: 8d4dd15db0ba863c213f743e33b5a207e948c980
Summary:
Haven't seen any production issues with new Bloom filter and
it's now > 1 year old (added in 6.6.0).
Updated check_format_compatible.sh and HISTORY.md
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8017
Test Plan: tests updated (or prior bugs fixed)
Reviewed By: ajkr
Differential Revision: D26762197
Pulled By: pdillinger
fbshipit-source-id: 0e755c46b443087c1544da0fd545beb9c403d1c2
Summary:
## 1. Bug description:
When RocksDB Checkpoint, it may be stuck in `WaitUntilFlushWouldNotStallWrites` method.
## 2. Simple analysis of the reasons:
### 2.1 Configuration parameters:
```yaml
Compaction Style : Universal
max_write_buffer_number : 4
min_write_buffer_number_to_merge : 3
```
Checkpoint is usually very fast. When the Checkpoint is executed, `WaitUntilFlushWouldNotStallWrites` is called. If there are 2 Immutable MemTables, which are less than `min_write_buffer_number_to_merge`, they will not be flushed. But will enter this code.
```c++
// method: GetWriteStallConditionAndCause
if (mutable_cf_options.max_write_buffer_number> 3 &&
num_unflushed_memtables >=
mutable_cf_options.max_write_buffer_number-1) {
return {WriteStallCondition::kDelayed, WriteStallCause::kMemtableLimit};
}
```
code link: fbed72f03c/db/column_family.cc (L847)
Checkpoint thought there was a FlushJob, but it didn't. So will always wait.
### 2.2 solution:
Increase the restriction: the `number of Immutable MemTable` >= `min_write_buffer_number_to_merge will wait`.
If there are other better solutions, you can correct me.
### 2.3 Code that can reproduce the problem:
https://github.com/1996fanrui/fanrui-learning/blob/flink-1.12/module-java/src/main/java/com/dream/rocksdb/RocksDBCheckpointStuck.java
## 3. Interesting point
This bug will be triggered only when `the number of sorted runs >= level0_file_num_compaction_trigger`.
Because there is a break in WaitUntilFlushWouldNotStallWrites.
```c++
if (cfd->imm()->NumNotFlushed() <
cfd->ioptions()->min_write_buffer_number_to_merge &&
vstorage->l0_delay_trigger_count() <
mutable_cf_options.level0_file_num_compaction_trigger) {
break;
}
```
code link: fbed72f03c/db/db_impl/db_impl_compaction_flush.cc (L1974)
Universal may have `l0_delay_trigger_count() >= level0_file_num_compaction_trigger`, so this bug is triggered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7921
Reviewed By: jay-zhuang
Differential Revision: D26900559
Pulled By: ajkr
fbshipit-source-id: 133c1252dad7393753f04a47590b68c7d8e670df
Summary:
For some reason I still cannot figure out, the manual flush in this test
was sometimes producing a third tiny file. I saw it a bunch of times on
ppc64le, but even running a qemu system with that architecture (and
playing with various other options) could not repro. However we did get
an instrumented Travis run to confirm the problem is indeed a third tiny
file - https://travis-ci.org/github/facebook/rocksdb/jobs/761986592. We
can avoid it by filling memtables less full and using manual flush.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8044
Reviewed By: akankshamahajan15
Differential Revision: D26892635
Pulled By: ajkr
fbshipit-source-id: 775c04176931cf01d07cc78fb82cfe3a11beebcf
Summary:
The patch does the following:
1) Exposes the amount of data (number of bytes) read from blob files from
`BlobFileReader::GetBlob` / `Version::GetBlob`.
2) Tracks the total number and size of blobs read from blob files during a
compaction (due to garbage collection or compaction filter usage) in
`CompactionIterationStats` and propagates this data to
`InternalStats::CompactionStats` / `CompactionJobStats`.
3) Updates the formulae for write amplification calculations to include the
amount of data read from blob files.
4) Extends the compaction stats dump with a new column `Rblob(GB)` and
a new line containing the total number and size of blob files in the current
`Version` to complement the information about the shape and size of the LSM tree
that's already there.
5) Updates `CompactionJobStats` so that the number of files and amount of data
written by a compaction are broken down per file type (i.e. table/blob file).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8022
Test Plan: Ran `make check` and `db_bench`.
Reviewed By: riversand963
Differential Revision: D26801199
Pulled By: ltamasi
fbshipit-source-id: 28a5f072048a702643b28cb5971b4099acabbfb2
Summary:
When changing db iterator direction, we may perform a reseek.
Therefore, we should bump the NUMBER_OF_RESEEKS_IN_ITERATION counter.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8015
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D26755415
Pulled By: riversand963
fbshipit-source-id: 211f51f1a454bcda768fc46c0dce51edeb7f05fe
Summary:
The patch breaks down the "bytes written" (as well as the "number of output files")
compaction statistics into two, so the values are logged separately for table files
and blob files in the info log, and are shown in separate columns (`Write(GB)` for table
files, `Wblob(GB)` for blob files) when the compaction statistics are dumped.
This will also come in handy for fixing the write amplification statistics, which currently
do not consider the amount of data read from blob files during compaction. (This will
be fixed by an upcoming patch.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8013
Test Plan: Ran `make check` and `db_bench`.
Reviewed By: riversand963
Differential Revision: D26742156
Pulled By: ltamasi
fbshipit-source-id: 31d18ee8f90438b438ca7ed1ea8cbd92114442d5
Summary:
The checkpointing logic supports passing file level checksums
to the copy_file_cb callback function which is used by the backup code
for detecting corruption during file copies.
However, this is currently implemented only for table files.
This PR extends the checksum retrieval to blob files as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8003
Test Plan: Add new test units
Reviewed By: ltamasi
Differential Revision: D26680701
Pulled By: akankshamahajan15
fbshipit-source-id: 1bd1e2464df6e9aa31091d35b8c72786d94cd1c5
Summary:
Allow applications to implement a custom compaction filter and pass it to BlobDB.
The compaction filter's custom logic can operate on blobs.
To do so, application needs to subclass `CompactionFilter` abstract class and implement `FilterV2()` method.
Optionally, a method called `ShouldFilterBlobByKey()` can be implemented if application's custom logic rely solely
on the key to make a decision without reading the blob, thus saving extra IO. Examples can be found in
db/blob/db_blob_compaction_test.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7974
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D26509280
Pulled By: riversand963
fbshipit-source-id: 59f9ae5614c4359de32f4f2b16684193cc537b39
Summary:
Fixed 5 test case failures found on Windows 10/Windows Server 2016
1. In `flush_job_test`, the DestroyDir function fails in deconstructor because some file handles are still being held by VersionSet. This happens on Windows Server 2016, so need to manually reset versions_ pointer to release all file handles.
2. In `StatsHistoryTest.InMemoryStatsHistoryPurging` test, the capping memory cost of stats_history_size on Windows becomes 14000 bytes with latest changes, not just 13000 bytes.
3. In `SSTDumpToolTest.RawOutput` test, the output file handle is not closed at the end.
4. In `FullBloomTest.OptimizeForMemory` test, ROCKSDB_MALLOC_USABLE_SIZE is undefined on windows so `total_mem` is always equal to `total_size`. The internal memory fragmentation assertion does not apply in this case.
5. In `BlockFetcherTest.FetchAndUncompressCompressedDataBlock` test, XPRESS cannot reach 87.5% compression ratio with original CreateTable method, so I append extra zeros to the string value to enhance compression ratio. Beside, since XPRESS allocates memory internally, thus does not support for custom allocator verification, we will skip the allocator verification for XPRESS
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7992
Reviewed By: jay-zhuang
Differential Revision: D26615283
Pulled By: ajkr
fbshipit-source-id: 3632612f84b99e2b9c77c403b112b6bedf3b125d
Summary:
Extend VerifyFileChecksums API to verify blob files in case of
use_file_checksum.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7979
Test Plan: New unit test db_blob_corruption_test
Reviewed By: ltamasi
Differential Revision: D26534040
Pulled By: akankshamahajan15
fbshipit-source-id: 7dc5951a3df9d265ea1265e0122b43c966856ade
Summary:
For dictionary compression, we need to collect some representative samples of the data to be compressed, which we use to either generate or train (when `CompressionOptions::zstd_max_train_bytes > 0`) a dictionary. Previously, the strategy was to buffer all the data blocks during flush, and up to the target file size during compaction. That strategy allowed us to randomly pick samples from as wide a range as possible that'd be guaranteed to land in a single output file.
However, some users try to make huge files in memory-constrained environments, where this strategy can cause OOM. This PR introduces an option, `CompressionOptions::max_dict_buffer_bytes`, that limits how much data blocks are buffered before we switch to unbuffered mode (which means creating the per-SST dictionary, writing out the buffered data, and compressing/writing new blocks as soon as they are built). It is not strict as we currently buffer more than just data blocks -- also keys are buffered. But it does make a step towards giving users predictable memory usage.
Related changes include:
- Changed sampling for dictionary compression to select unique data blocks when there is limited availability of data blocks
- Made use of `BlockBuilder::SwapAndReset()` to save an allocation+memcpy when buffering data blocks for building a dictionary
- Changed `ParseBoolean()` to accept an input containing characters after the boolean. This is necessary since, with this PR, a value for `CompressionOptions::enabled` is no longer necessarily the final component in the `CompressionOptions` string.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7970
Test Plan:
- updated `CompressionOptions` unit tests to verify limit is respected (to the extent expected in the current implementation) in various scenarios of flush/compaction to bottommost/non-bottommost level
- looked at jemalloc heap profiles right before and after switching to unbuffered mode during flush/compaction. Verified memory usage in buffering is proportional to the limit set.
Reviewed By: pdillinger
Differential Revision: D26467994
Pulled By: ajkr
fbshipit-source-id: 3da4ef9fba59974e4ef40e40c01611002c861465
Summary:
Added a "only_mutable_options" flag to the ConfigOptions. When set, the Configurable methods will only look at/update options that are marked as kMutable.
Fixed DB::SetOptions to allow for the update of any mutable TableFactory options. Fixes https://github.com/facebook/rocksdb/issues/7385.
Added tests for the new flag. Updated HISTORY.md
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7936
Reviewed By: akankshamahajan15
Differential Revision: D26389646
Pulled By: mrambacher
fbshipit-source-id: 6dc247f6e999fa2814059ebbd0af8face109fea0
Summary:
The trace file record and payload encode is fixed, which requires complex backward compatibility resolving. This PR introduce a new trace file format, which makes it easier to add new entries to the payload and does not have backward compatible issues. V 0.1 is still supported in this PR. Added the tracing for lower_bound and upper_bound for iterator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7977
Test Plan: make check. tested with old trace file in replay and analyzing.
Reviewed By: anand1976
Differential Revision: D26529948
Pulled By: zhichao-cao
fbshipit-source-id: ebb75a127ce3c07c25a1ccc194c551f917896a76
Summary:
TransactionDB uses read callback to filter out un-committed data before
a snapshot. But `MultiGet()` API doesn't use that at all, which causes
returning unwanted data.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7963
Test Plan: Added unittest to reproduce
Reviewed By: anand1976
Differential Revision: D26455851
Pulled By: jay-zhuang
fbshipit-source-id: 265276698cf9d8c4cd79e3250ef10d14375bac55
Summary:
Bug fix for status returned being overridden by Status::NotFound in
DBImpl::OpenForReadOnlyCheckExistence. This was casuing some service
owners to misinterpret the actual error and take appropriate steps.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7972
Reviewed By: riversand963
Differential Revision: D26499598
Pulled By: akankshamahajan15
fbshipit-source-id: 05e9fedbe2a2e0e53135760f8ff578a2816d2b8e
Summary:
Add support for IOTracing in blob files
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7958
Test Plan:
Add a new test and checked manually the trace_file for blob
files being recorded during read and write.
Reviewed By: ltamasi
Differential Revision: D26415950
Pulled By: akankshamahajan15
fbshipit-source-id: 49c2859b3a4f8307e7cb69a92704403a4da46d44
Summary:
in PR https://github.com/facebook/rocksdb/issues/7419 , we introduce the new Append and PositionedAppend APIs to WritableFile at File System, which enable RocksDB to pass the data verification information (e.g., checksum of the data) to the lower layer. In this PR, we use the new API in WritableFileWriter, such that the file created via WritableFileWrite can pass the checksum to the storage layer. To control which types file should apply the checksum handoff, we add checksum_handoff_file_types to DBOptions. User can use this option to control which file types (Currently supported file tyes: kLogFile, kTableFile, kDescriptorFile.) should use the new Append and PositionedAppend APIs to handoff the verification information.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7523
Test Plan: add new unit test, pass make check/ make asan_check
Reviewed By: pdillinger
Differential Revision: D24313271
Pulled By: zhichao-cao
fbshipit-source-id: aafd69091ae85c3318e3e17cbb96fe7338da11d0
Summary:
Memtable bloom filter is useful in many use cases. A default value on with conservative 1.5% memory can benefit more use cases than use cases impacted.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6584
Test Plan: Run all existing tests.
Reviewed By: pdillinger
Differential Revision: D20626739
fbshipit-source-id: 1dd45532b932139552519b8c2682bd954550c2f9
Summary:
There is a small `SingleDelete` related optimization in the
`CompactionIterator` code: when a `SingleDelete`-`Put` pair is preserved
solely for the purposes of transaction conflict checking, the value
itself gets cleared. (This is referred to as "optimization 3" in the
`CompactionIterator` code.) Though the rest of the code got updated to
support `SingleDelete`'ing blob indexes, this chunk was apparently
missed, resulting in an assertion failure (or `ROCKS_LOG_FATAL` in release
builds) when triggered. Note: in addition to clearing the value, we also
need to update the type of the KV to regular value when dealing with
blob indexes here.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7904
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D26118009
Pulled By: ltamasi
fbshipit-source-id: 6bf78043d20265e2b15c2e1ab8865025040c42ae
Summary:
This PR adds the foundation classes for key-value integrity protection and the first use case: protecting live updates from the source buffers added to `WriteBatch` through the destination buffer in `MemTable`. The width of the protection info is not yet configurable -- only eight bytes per key is supported. This PR allows users to enable protection by constructing `WriteBatch` with `protection_bytes_per_key == 8`. It does not yet expose a way for users to get integrity protection via other write APIs (e.g., `Put()`, `Merge()`, `Delete()`, etc.).
The foundation classes (`ProtectionInfo.*`) embed the coverage info in their type, and provide `Protect.*()` and `Strip.*()` functions to navigate between types with different coverage. For making bytes per key configurable (for powers of two up to eight) in the future, these classes are templated on the unsigned integer type used to store the protection info. That integer contains the XOR'd result of hashes with independent seeds for all covered fields. For integer fields, the hash is computed on the raw unadjusted bytes, so the result is endian-dependent. The most significant bytes are truncated when the hash value (8 bytes) is wider than the protection integer.
When `WriteBatch` is constructed with `protection_bytes_per_key == 8`, we hold a `ProtectionInfoKVOTC` (i.e., one that covers key, value, optype aka `ValueType`, timestamp, and CF ID) for each entry added to the batch. The protection info is generated from the original buffers passed by the user, as well as the original metadata generated internally. When writing to memtable, each entry is transformed to a `ProtectionInfoKVOTS` (i.e., dropping coverage of CF ID and adding coverage of sequence number), since at that point we know the sequence number, and have already selected a memtable corresponding to a particular CF. This protection info is verified once the entry is encoded in the `MemTable` buffer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7748
Test Plan:
- an integration test to verify a wide variety of single-byte changes to the encoded `MemTable` buffer are caught
- add to stress/crash test to verify it works in variety of configs/operations without intentional corruption
- [deferred] unit tests for `ProtectionInfo.*` classes for edge cases like KV swap, `SliceParts` and `Slice` APIs are interchangeable, etc.
Reviewed By: pdillinger
Differential Revision: D25754492
Pulled By: ajkr
fbshipit-source-id: e481bac6c03c2ab268be41359730f1ceb9964866
Summary:
Removed the uses of the Legacy FileWrapper classes from the source code. The wrappers were creating an additional layer of indirection/wrapping, as the Env already has a FileSystem.
Moved the Custom FileWrapper classes into the CustomEnv, as these classes are really for the private use the the CustomEnv class.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7851
Reviewed By: anand1976
Differential Revision: D26114816
Pulled By: mrambacher
fbshipit-source-id: db32840e58d969d3a0fa6c25aaf13d6dcdc74150
Summary:
Closes https://github.com/facebook/rocksdb/issues/7035
Changed how build_version.cc was generated:
- Included the GIT tag/branch in the build_version file
- Changed the "Build Date" to be:
- If the GIT branch is "clean" (no changes), the date of the last git commit
- If the branch is not clean, the current date
- Added APIs to access the "build information", rather than accessing the strings directly.
The build_version.cc file is now regenerated whenever the library objects are rebuilt.
Verified that the built files remain the same size across builds on a "clean build" and the same information is reported by sst_dump --version
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7866
Reviewed By: pdillinger
Differential Revision: D26086565
Pulled By: mrambacher
fbshipit-source-id: 6fcbe47f6033989d5cf26a0ccb6dfdd9dd239d7f
Summary:
During recovery, RocksDB performs a kind of dummy flush; namely, entries
from the WAL are added to memtables, which then get written to SSTs and
blob files (if enabled) just like during a regular flush. Note that
multiple memtables might be flushed during recovery for the same column
family, for example, if the DB is reopened with a lower write buffer size,
and therefore, we need to make sure to collect all SST and blob file
additions. The patch fixes a bug in the earlier logic which resulted in
later blob file additions overwriting earlier ones.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7903
Test Plan: Added a unit test and ran `db_stress`.
Reviewed By: jay-zhuang
Differential Revision: D26110847
Pulled By: ltamasi
fbshipit-source-id: eddb50a608a88f54f3cec3a423de8235aba951fd
Summary:
When retryable IO error occurs during compaction, it is mapped to soft error and set the BG error. However, auto resume is not called to clean the soft error since compaction will reschedule by itself. In this change, When retryable IO error occurs during compaction, BG error is not set. User will be informed the error via EventHelper.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7899
Test Plan: tested with error_handler_fs_test
Reviewed By: anand1976
Differential Revision: D26094097
Pulled By: zhichao-cao
fbshipit-source-id: c53424f11d237405592cd762f43cbbdf8da8234f
Summary:
The recovery thread could hold the db.mutex, which is needed from sync
write in main thread.
Make sure the write is done before recovery thread starts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7897
Test Plan: `gtest-parallel ./error_handler_fs_test --gtest_filter=DBErrorHandlingFSTest.WALWriteRetryableErrorAutoRecover1 -r 10000 --workers=200`
Reviewed By: zhichao-cao
Differential Revision: D26082933
Pulled By: jay-zhuang
fbshipit-source-id: 226fc49228c0e5903f86ff45cc3fed3080abdb1f
Summary:
The error recovery thread may out-live DBImpl object, which causing
access released DBImpl.mutex. Close SstFileManager before closing DB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7896
Test Plan:
the issue can be reproduced by adding sleep in recovery code.
Pass the tests with sleep.
Reviewed By: zhichao-cao
Differential Revision: D26076655
Pulled By: jay-zhuang
fbshipit-source-id: 0d9cc5639c12fcfc001427015e75a9736f33cd96
Summary:
Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock.
Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock.
There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc).
Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858
Reviewed By: pdillinger
Differential Revision: D26006406
Pulled By: mrambacher
fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
Summary:
1. In IOTracing, add filename with each IOTrace record. Filename is stored in file object (Tracing Wrappers).
2. Change the logic of figuring out which additional information (file_size,
length, offset etc) needs to be store with each operation
which is different for different operations.
When new information will be added in future (depends on operation),
this change would make the future additions simple.
Logic: In IOTraceRecord, io_op_data is added and its
bitwise positions represent which additional information need
to added in the record from enum IOTraceOp. Values in IOTraceOp represent bitwise positions.
So if length and offset needs to be stored (IOTraceOp::kIOLen
is 1 and IOTraceOp::kIOOffset is 2), position 1 and 2 (from rightmost bit) will be set
and io_op_data will contain 110.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7885
Test Plan: Updated io_tracer_test and verified the trace file manually.
Reviewed By: anand1976
Differential Revision: D25982353
Pulled By: akankshamahajan15
fbshipit-source-id: ebfc5539cc0e231d7794a6b42b73f5403e360b22
Summary:
In the original stacked BlobDB implementation, which writes blobs to blob files
immediately and treats blob files as logs, it makes sense to flush the file after
writing each blob to protect against process crashes; however, in the integrated
implementation, which builds blob files in the background jobs, this unnecessarily
reduces performance. This patch fixes this by simply adding a `do_flush` flag to
`BlobLogWriter`, which is set to `true` by the stacked implementation and to `false`
by the new code. Note: the change itself is trivial but the tests needed some work;
since in the new implementation, blobs are now buffered, adding a blob to
`BlobFileBuilder` is no longer guaranteed to result in an actual I/O. Therefore, we can
no longer rely on `FaultInjectionTestEnv` when testing failure cases; instead, we
manipulate the return values of I/O methods directly using `SyncPoint`s.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7892
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D26022814
Pulled By: ltamasi
fbshipit-source-id: b3dce419f312137fa70d84cdd9b908fd5d60d8cd
Summary:
…when unused. Causes many calls to clock_gettime, impacting performance.
Was looking for something else via Linux "perf" command when I spotted heavy usage of clock_gettime during a compaction. Our product heavily uses the rocksdb::Options::merge_operator. MergeHelper::FilterMerge() properly tests if timing is enabled/disabled upon entry, but not on exit. This patch fixes the exit.
Note: the entry test also verifies if "nullptr!=stats_". This test is redundant to code within ShouldReportDetailedTime(). Therefore I omitted it in my change.
merge_test.cc updated with test that shows failure before merge_helper.cc change ... and fix after change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7867
Reviewed By: jay-zhuang
Differential Revision: D25960175
Pulled By: ajkr
fbshipit-source-id: 56e66d7eb6ae5eae89c8e0d5a262bd2905a226b6
Summary:
This provides a workaround for two race conditions that will be fixed in
a more sophisticated way later. This PR:
(1) Makes the client serialize calls to `Timer::Start()` and `Timer::Shutdown()` (see https://github.com/facebook/rocksdb/issues/7711). The long-term fix will be to make those functions thread-safe.
(2) Makes `PeriodicWorkScheduler` atomically add/cancel work together with starting/shutting down its `Timer`. The long-term fix will be for `Timer` API to offer more specialized APIs so the client will not need to synchronize.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7888
Test Plan: ran the repro provided in https://github.com/facebook/rocksdb/issues/7881
Reviewed By: jay-zhuang
Differential Revision: D25990891
Pulled By: ajkr
fbshipit-source-id: a97fdaebbda6d7db7ddb1b146738b68c16c5be38
Summary:
BlobFileAddition and BlobFileGarbage should not be in the ignorable tag
range, since if they are present in the MANIFEST, users cannot downgrade
to a RocksDB version that does not understand them without losing access
to the data in the blob files. The patch moves these two tags to the
unignorable range; this should still be safe at this point, since the
integrated BlobDB project is still work in progress and thus there
shouldn't be any ignorable BlobFileAddition/BlobFileGarbage tags out
there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7886
Test Plan: `make check`
Reviewed By: cheng-chang
Differential Revision: D25980956
Pulled By: ltamasi
fbshipit-source-id: 13cf5bd61d77f049b513ecd5ad0be8c637e40a9d
Summary:
Although the tags for `WalAddition`, `WalDeletion` are after `kTagSafeIgnoreMask`, to actually be able to skip these entries in older versions of RocksDB, we require that they are encoded with their encoded size as the prefix. This requirement is not met in the current codebase, so a downgraded DB may fail to open if these entries exist in the MANIFEST.
If a DB wants to downgrade, and its MANIFEST contains `WalAddition` or `WalDeletion`, it can set `track_and_verify_wals_in_manifest` to `false`, then restart twice, then downgrade. On the first restart, a new MANIFEST will be created with a `WalDeletion` indicating that all previously tracked WALs are removed from MANIFEST. On the second restart, since there is no tracked WALs in MANIFEST now, a new MANIFEST will be created with neither `WalAddition` nor `WalDeletion`. Then the DB can downgrade.
Tags for `BlobFileAddition`, `BlobFileGarbage` also have the same problem, but this PR focuses on solving the problem for WAL edits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7873
Test Plan: Added a `VersionEditTest::IgnorableTags` unit test to verify all entries with tags larger than `kTagSafeIgnoreMask` can actually be skipped and won't affect parsing of other entries.
Reviewed By: ajkr
Differential Revision: D25935930
Pulled By: cheng-chang
fbshipit-source-id: 7a02fdba4311d6084328c14aed110a26d08c3efb
Summary:
The WAL's file size is stored as an unsigned 64 bit integer.
In db_info_dumper.cc, this integer gets converted to a string. Since 2^64 is approximately 10^19, we need 20 digits to represent the integer correctly. To store the decimal representation, we need 21 bytes (+1 due to the '\0' terminator at the end). The code previously used 16 bytes, which would overflow if the log is really big (>1 petabyte).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7870
Reviewed By: ajkr
Differential Revision: D25938776
Pulled By: jay-zhuang
fbshipit-source-id: 6ee9e21ebd65d297ea90fa1e7e74f3e1c533299d
Summary:
The main improvement here is to not include `.` or `..` in the results of `Env::GetChildren`. The occurrence of `.` or `..`; it is non-portable, dependent on the Operating System and the File System. See: https://www.gnu.org/software/libc/manual/html_node/Reading_002fClosing-Directory.html
There were lots of duplicate checks spread through the RocksDB codebase previously to skip `.` and `..`. This new removes the need for those at the source.
Also some minor fixes to `Env::GetChildren`:
* Improve error handling in POSIX implementation
* Remove unnecessary array allocation on Windows
* Fix struct name for Windows Non-UTF-8 API
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7819
Reviewed By: ajkr
Differential Revision: D25837394
Pulled By: jay-zhuang
fbshipit-source-id: 1e137e7218d38b450af9c083f73d5357abcbba2e
Summary:
In RocksDB, when IO error happens, the flags of IOStatus can be set. If the IOStatus is set as "File Scope IO Error", it indicate that the error is constrained in the file level. Since RocksDB does not continues write data to a file when any IO Error happens, File Scope IO Error can be treated the same as Retryable IO Error. Adding the logic to ErrorHandler::SetBGError to include the file scope IO Error in its error handling logic, which is the same as retryable IO Error.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7840
Test Plan: added new unit tests in error_handler_fs_test. make check
Reviewed By: anand1976
Differential Revision: D25820481
Pulled By: zhichao-cao
fbshipit-source-id: 69cabd3d010073e064d6142ce1cabf341b8a6806
Summary:
The IOStatus of TableBuilder is returned by copy the io status from builder->io_status(). pr https://github.com/facebook/rocksdb/issues/7718 swallowed the io status and it will cause the write IO error become non-retryable and no auto resume logic will handle it. Roll back to previous implementation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7838
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D25795387
Pulled By: zhichao-cao
fbshipit-source-id: bc35e69e0b71aa4148a6ed76f073357041b8e372
Summary:
This PR does the following:
-> Creates a WinFileSystem class. This class is the Windows equivalent of the PosixFileSystem and will be used on Windows systems.
-> Introduces a CustomEnv class. A CustomEnv is an Env that takes a FileSystem as constructor argument. I believe there will only ever be two implementations of this class (PosixEnv and WinEnv). There is still a CustomEnvWrapper class that takes an Env and a FileSystem and wraps the Env calls with the input Env but uses the FileSystem for the FileSystem calls
-> Eliminates the public uses of the LegacyFileSystemWrapper.
With this change in place, there are effectively the following patterns of Env:
- "Base Env classes" (PosixEnv, WinEnv). These classes implement the core Env functions (e.g. Threads) and have a hard-coded input FileSystem. These classes inherit from CompositeEnv, implement the core Env functions (threads) and delegate the FileSystem-like calls to the input file system.
- Wrapped Composite Env classes (MemEnv). These classes take in an Env and a FileSystem. The core env functions are re-directed to the wrapped env. The file system calls are redirected to the input file system
- Legacy Wrapped Env classes. These classes take in an Env input (but no FileSystem). The core env functions are re-directed to the wrapped env. A "Legacy File System" is created using this env and the file system calls directed to the env itself.
With these changes in place, the PosixEnv becomes a singleton -- there is only ever one created. Any other use of the PosixEnv is via another wrapped env. This cleans up some of the issues with the env construction and destruction.
Additionally, there were places in the code that required had an Env when they required a FileSystem. Many of these places would wrap the Env with a LegacyFileSystemWrapper instead of using the env->GetFileSystem(). These places were changed, thereby removing layers of additional redirection (LegacyFileSystem --> Env --> Env::FileSystem).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7703
Reviewed By: zhichao-cao
Differential Revision: D25762190
Pulled By: anand1976
fbshipit-source-id: 1a088e97fc916f28ac69c149cd1dcad0ab31704b
Summary:
Change the StringEnv and related classes to be based on FileSystem APIs rather than the corresponding Env ones. The StringSink and StringSource classes were changed to be based on the corresponding FS file classes.
Part of a cleanup to use the newer interfaces. This change also eliminates some of the casts/wrappers to LegacyFile classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7786
Reviewed By: jay-zhuang
Differential Revision: D25761460
Pulled By: anand1976
fbshipit-source-id: 428ae8e32b3db97dbeeca08c9d3bb0d9d4d3a38f
Summary:
Previously we only had a debug assertion to check the right generator was being used for verification. However a user hit a problem in production where their factory was creating the wrong generator for some files, leading to checksum mismatches. It would have been easier to debug if we verified in optimized builds that the generator with the proper name is used. This PR adds such verification.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7824
Reviewed By: zhichao-cao
Differential Revision: D25740254
Pulled By: ajkr
fbshipit-source-id: a6231521747605021bad3231484b5d4f99f4044f
Summary:
The returned Status is ignored here as some stress tests are failing, presumably when attempting to add an empty file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7826
Reviewed By: jay-zhuang
Differential Revision: D25742931
fbshipit-source-id: a1fcd620d9472993a009929306dfc421f93eb43b
Summary:
In GenerateOneFileChecksum(), RocksDB reads the file and computes its checksum. A rate limiter can be passed to the constructor of RandomAccessFileReader so that read I/O can be rate limited.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7811
Test Plan: make check
Reviewed By: cheng-chang
Differential Revision: D25699896
Pulled By: zhichao-cao
fbshipit-source-id: e2688bc1126c543979a3bcf91dda784bd7b74164
Summary:
Added "no-elide-constructors to the ASSERT_STATUS_CHECK builds. This flag gives more errors/warnings for some of the Status checks where an inner class checks a Status and later returns it. In this case, without the elide check on, the returned status may not have been checked in the caller, thereby bypassing the checked code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7798
Reviewed By: jay-zhuang
Differential Revision: D25680451
Pulled By: pdillinger
fbshipit-source-id: c3f14ed9e2a13f0a8c54d839d5fb4d1fc1e93917
Summary:
RetrieveMultipleBlocks which is used by MultiGet to read data blocks is not updating num_data_read stat in
GetContextStats.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7770
Test Plan: make check -j64
Reviewed By: anand1976
Differential Revision: D25538982
Pulled By: akankshamahajan15
fbshipit-source-id: e3daedb035b1be8ab6af6f115cb3793ccc7b1ec6
Summary:
This test would occasionally fail like this:
WARNING: c:\users\circleci\project\db\db_test.cc(1343): error: Expected:
(dbfull()->TEST_MaxNextLevelOverlappingBytes(handles_[1])) <= (20 * 1048576), actual: 33501540 vs 20971520
And being a super old test, it's not structured in a sound way. And it appears that DBTest2.MaxCompactionBytesTest is a better test of what SparseMerge was intended to test. In fact, SparseMerge fails if I set
options.max_compaction_bytes = options.target_file_size_base * 1000;
Thus, we are removing this negative-value test.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7800
Test Plan: Q.E.D.
Reviewed By: ajkr
Differential Revision: D25693366
Pulled By: pdillinger
fbshipit-source-id: 9da07d4dce0559547fc938b2163a2015e956c548
Summary:
`CompactedDB` is a kind of read-only DB, so it shouldn't support `SyncWAL`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7788
Test Plan: watch existing tests to pass.
Reviewed By: akankshamahajan15
Differential Revision: D25661209
Pulled By: cheng-chang
fbshipit-source-id: 9eb2cc3f73736dcc205c8410e5944aa203f002d3
Summary:
We saw DBWALTestWithParam/DBWALTestWithParam.WALTrashCleanupOnOpen sometimes fail with:
db/db_sst_test.cc:575: Failure
Expected: (trash_log_count) >= (1), actual: 0 vs 1
The suspicious is that delete scheduling actually deleted all trash files based on rate, but it is not expected. This can be reproduced if we manually add sleep after DB is closed for serveral seconds. Minimize its chance by setting the delete rate to be lowest possible.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7796
Test Plan: The test doesn't fail with the manual sleeping anymore
Reviewed By: anand1976
Differential Revision: D25675000
fbshipit-source-id: a39fd05e1a83719c41014e48843792e752368e22
Summary:
So that we can more easily get aggregate live table data such
as total filter, index, and data sizes.
Also adds ldb support for getting properties
Also fixed some missing/inaccurate related comments in db.h
For example:
$ ./ldb --db=testdb get_property rocksdb.aggregated-table-properties
rocksdb.aggregated-table-properties.data_size: 102871
rocksdb.aggregated-table-properties.filter_size: 0
rocksdb.aggregated-table-properties.index_partitions: 0
rocksdb.aggregated-table-properties.index_size: 2232
rocksdb.aggregated-table-properties.num_data_blocks: 100
rocksdb.aggregated-table-properties.num_deletions: 0
rocksdb.aggregated-table-properties.num_entries: 15000
rocksdb.aggregated-table-properties.num_merge_operands: 0
rocksdb.aggregated-table-properties.num_range_deletions: 0
rocksdb.aggregated-table-properties.raw_key_size: 288890
rocksdb.aggregated-table-properties.raw_value_size: 198890
rocksdb.aggregated-table-properties.top_level_index_size: 0
$ ./ldb --db=testdb get_property rocksdb.aggregated-table-properties-at-level1
rocksdb.aggregated-table-properties-at-level1.data_size: 80909
rocksdb.aggregated-table-properties-at-level1.filter_size: 0
rocksdb.aggregated-table-properties-at-level1.index_partitions: 0
rocksdb.aggregated-table-properties-at-level1.index_size: 1787
rocksdb.aggregated-table-properties-at-level1.num_data_blocks: 81
rocksdb.aggregated-table-properties-at-level1.num_deletions: 0
rocksdb.aggregated-table-properties-at-level1.num_entries: 12466
rocksdb.aggregated-table-properties-at-level1.num_merge_operands: 0
rocksdb.aggregated-table-properties-at-level1.num_range_deletions: 0
rocksdb.aggregated-table-properties-at-level1.raw_key_size: 238210
rocksdb.aggregated-table-properties-at-level1.raw_value_size: 163414
rocksdb.aggregated-table-properties-at-level1.top_level_index_size: 0
$
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7779
Test Plan: Added a test to ldb_test.py
Reviewed By: jay-zhuang
Differential Revision: D25653103
Pulled By: pdillinger
fbshipit-source-id: 2905469a08a64dd6b5510cbd7be2e64d3234d6d3
Summary:
In the write path, there is an optimization: when a new WAL is created during SwitchMemtable, we update the internal log number of the empty column families to the new WAL. `FindObsoleteFiles` marks a WAL as obsolete if the WAL's log number is less than `VersionSet::MinLogNumberWithUnflushedData`. After updating the empty column families' internal log number, `VersionSet::MinLogNumberWithUnflushedData` might change, so some WALs might become obsolete to be purged from disk.
For example, consider there are 3 column families: 0, 1, 2:
1. initially, all the column families' log number is 1;
2. write some data to cf0, and flush cf0, but the flush is pending;
3. now a new WAL 2 is created;
4. write data to cf1 and WAL 2, now cf0's log number is 1, cf1's log number is 2, cf2's log number is 2 (because cf1 and cf2 are empty, so their log numbers will be set to the highest log number);
5. now cf0's flush hasn't finished, flush cf1, a new WAL 3 is created, and cf1's flush finishes, now cf0's log number is 1, cf1's log number is 3, cf2's log number is 3, since WAL 1 still contains data for the unflushed cf0, no WAL can be deleted from disk;
6. now cf0's flush finishes, cf0's log number is 2 (because when cf0 was switching memtable, WAL 3 does not exist yet), cf1's log number is 3, cf2's log number is 3, so WAL 1 can be purged from disk now, but WAL 2 still cannot because `MinLogNumberToKeep()` is 2;
7. write data to cf2 and WAL 3, because cf0 is empty, its log number is updated to 3, so now cf0's log number is 3, cf1's log number is 3, cf2's log number is 3;
8. now if the background threads want to purge obsolete files from disk, WAL 2 can be purged because `MinLogNumberToKeep()` is 3. But there are only two flush results written to MANIFEST: the first is for flushing cf1, and the `MinLogNumberToKeep` is 1, the second is for flushing cf0, and the `MinLogNumberToKeep` is 2. So without this PR, if the DB crashes at this point and try to recover, `WalSet` will still expect WAL 2 to exist.
When WAL tracking is enabled, we assume WALs will only become obsolete after a flush result is written to MANIFEST in `MemtableList::TryInstallMemtableFlushResults` (or its atomic flush counterpart). The above situation breaks this assumption.
This PR tracks WAL obsoletion if necessary before updating the empty column families' log numbers.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7781
Test Plan:
watch existing tests and stress tests to pass.
`make -j48 blackbox_crash_test` on devserver
Reviewed By: ltamasi
Differential Revision: D25631695
Pulled By: cheng-chang
fbshipit-source-id: ca7fff967bdb42204b84226063d909893bc0a4ec
Summary:
When ConcurrentTaskLimiter is enabled and there are too many outstanding compactions, BackgroundCompaction returns Status::Busy(), which shouldn't be treat as compaction failure.
This caused performance issue when outstanding compactions reached the limit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7739
Reviewed By: cheng-chang
Differential Revision: D25508319
Pulled By: ltamasi
fbshipit-source-id: 3b181b16ada0ca3393cfa3a7412985764e79c719
Summary:
sst file number in corruption error would be very useful for debugging
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7767
Reviewed By: zhichao-cao
Differential Revision: D25485872
Pulled By: jay-zhuang
fbshipit-source-id: 67315b582cedeefbce6676015303ebe5bf6526a3
Summary:
The patch adds initial support for reading blobs to the batched `MultiGet` API.
The current implementation simply retrieves the blob values as the blob indexes
are encountered; that is, reads from blob files are currently not batched. (This
will be optimized in a separate phase.) In addition, the patch removes some dead
code related to BlobDB from the batched `MultiGet` implementation, namely the
`is_blob` / `is_blob_index` flags that are passed around in `DBImpl` and `MemTable` /
`MemTableListVersion`. These were never hooked up to anything and wouldn't
work anyways, since a single flag is not sufficient to communicate the "blobness"
of multiple key-values.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7766
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D25479290
Pulled By: ltamasi
fbshipit-source-id: 7aba2d290e31876ee592bcf1adfd1018713a8000
Summary:
Uncommon bug seen by ASAN with
ColumnFamilyTest.LiveIteratorWithDroppedColumnFamily, if the last two
references to a ColumnFamilyData are both SuperVersions (during
InstallSuperVersion). The fix is to use UnrefAndTryDelete even in
SuperVersion::Cleanup but with a parameter to avoid re-entering Cleanup
on the same SuperVersion being cleaned up.
ColumnFamilyData::Unref is considered unsafe so removed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7749
Test Plan: ./column_family_test --gtest_filter=*LiveIter* --gtest_repeat=100
Reviewed By: jay-zhuang
Differential Revision: D25354304
Pulled By: pdillinger
fbshipit-source-id: e78f3a3f67c40013b8432f31d0da8bec55c5321c
Summary:
min_wal_number_to_keep should not be decreasing, if it does not increase, then there is no need to log the WAL obsoletions in MANIFEST since a previous one has been logged.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7765
Test Plan: watch existing tests and stress tests to pass
Reviewed By: pdillinger
Differential Revision: D25462542
Pulled By: cheng-chang
fbshipit-source-id: 0085fcb6edf5cf2b0fc32f9932a7566f508768ff
Summary:
When two phase commit is enabled, `VersionSet::min_log_number_to_keep_2pc` is set during flush.
But when a new MANIFEST is created, the `min_log_number_to_keep_2pc` is not carried over to the new MANIFEST. So if a new MANIFEST is created and then DB is reopened, the `min_log_number_to_keep_2pc` will be lost. This may cause DB recovery errors.
The bug is reproduced in a new unit test in `version_set_test.cc`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7747
Test Plan: The new unit test in `version_set_test.cc` should pass.
Reviewed By: jay-zhuang
Differential Revision: D25350661
Pulled By: cheng-chang
fbshipit-source-id: eee890d5b19f15769069670692e270ae31044ece
Summary:
Ensure that when direct IO is enabled and a compressed block cache is
configured, MultiGet inserts compressed data blocks into the compressed
block cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7756
Test Plan: Add unit test to db_basic_test
Reviewed By: cheng-chang
Differential Revision: D25416240
Pulled By: anand1976
fbshipit-source-id: 75d57526370c9c0a45ff72651f3278dbd8a9086f
Summary:
If WAL tracking was enabled, then disabled during reopen, the previously tracked WALs should be removed from MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7757
Test Plan: a new unit test `DBBasicTest.DisableTrackWal` is added.
Reviewed By: jay-zhuang
Differential Revision: D25410508
Pulled By: cheng-chang
fbshipit-source-id: 9d8d9e665066135930a7c1035bb8c2f68bded6a0
Summary:
Currently, when a WAL becomes obsolete after flushing, if VersionSet::WalSet does not contain the WAL, we do not track the WAL obsoletion event in MANIFEST.
But consider this case:
* WAL 10 is synced, a VersionEdit is LogAndApplied to MANIFEST to log this WAL addition event, but the VersionEdit is not applied to WalSet yet since its corresponding ManifestWriter is still pending in the write queue;
* Since the above ManifestWriter is blocking, the LogAndApply will block on a conditional variable and release the db mutex, so another LogAndApply can proceed to enqueue other VersionEdits concurrently;
* Now flush happens, and WAL 10 becomes obsolete, although WalSet does not contain WAL 10 yet, we should call LogAndApply to enqueue a VersionEdit to indicate the obsoletion of WAL 10;
* otherwise, when the queued edit indicating WAL 10 addition is logged to MANIFEST, and DB crashes and reopens, the WAL 10 might have been removed from disk, but it still exists in MANIFEST.
This PR changes the behavior to: always `LogAndApply` any WAL addition or obsoletion event, without considering the order issues caused by concurrency, but when applying the edits to `WalSet`, do not add the WALs if they are already obsolete. In this approach, the logical events of WAL addition and obsoletion are always tracked in MANIFEST, so we can inspect the MANIFEST and know all the previous WAL events, but we choose to ignore certain events due to the concurrency issues such as the case above, or the case in https://github.com/facebook/rocksdb/pull/7725.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7759
Test Plan: make check
Reviewed By: pdillinger
Differential Revision: D25423089
Pulled By: cheng-chang
fbshipit-source-id: 9cb9a7fbc1875bf954f2a42f9b6cfd6d49a7b21c
Summary:
Consider the case:
1. All column families are flushed, so all WALs become obsolete, but no WAL is removed from disk yet because the removal is asynchronous, a VersionEdit is written to MANIFEST indicating that WALs before a certain WAL number are obsolete, let's say this number is 3;
2. `SyncWAL` is called, so all the on-disk WALs are synced, and if track_and_verify_wal_in_manifest=true, the WALs will be tracked in MANIFEST, let's say the WAL numbers are 1 and 2;
3. DB crashes;
4. During DB recovery, when replaying MANIFEST, we first see that WAL with number < 3 are obsolete, then we see that WAL 1 and 2 are synced, so according to current implementation of `WalSet`, the `WalSet` will be recovered to include WAL 1 and 2;
5. WAL 1 and 2 are asynchronously deleted from disk, then the WAL verification algorithm fails with `Corruption: missing WAL`.
The above case is reproduced in a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal`.
The fix is to maintain the upper bound of the obsolete WAL numbers, any WAL with number less than the maintained number is considered to be obsolete, so shouldn't be tracked even if they are later synced. The number is maintained in `WalSet`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7725
Test Plan:
1. a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal` is added.
2. run `make crash_test` on devserver.
Reviewed By: riversand963
Differential Revision: D25238914
Pulled By: cheng-chang
fbshipit-source-id: f5dccd57c3d89f19565ec5731f2d42f06d272b72
Summary:
This PR removes a nested loop inside ProcessManifestWrites. The new
implementation has the same behavior as the old code with simpler logic
and lower complexity.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7751
Test Plan:
make check
Run make crash_test on devserver and succeeds 3 times.
Reviewed By: ltamasi
Differential Revision: D25363526
Pulled By: riversand963
fbshipit-source-id: 27e681949dacd7501a752e5e517b9e85b54ccb2e
Summary:
This change eliminates the need for a lot of the PermitUncheckedError calls on return from ErrorHandler methods. The calls are no longer needed as the status is returned as a reference rather than a copy. Additionally, this means that the originating status (recovery_error_, bg_error_) is not cleared implicitly as a result of calling one of these methods.
For this class, I do not know if the proper behavior should be to call PermitUncheckedError in the destructor or if the checked state should be cleared when the status is cleared. I did tests both ways. Without the code in the destructor, the status will need to be cleared in at least some of the places where it is set to OK. When running tests, I found no instances where this class was destructed with a non-OK, non-checked Status.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7539
Reviewed By: anand1976
Differential Revision: D25340565
Pulled By: pdillinger
fbshipit-source-id: 1730c035c81a475875ea745226112030ec25136c
Summary:
`googletest` uses exceptions to communicate assertion failures when
`GTEST_THROW_ON_FAILURE` is set, which does not go well with
`std::thread`s, since an exception escaping the top-level function of an
`std::thread` object or an `std::thread` getting destroyed without
having been `join`ed or `detach`ed first results in a call to
`std::terminate`. The patch fixes this by moving the `Status` assertions
of background operations in `ExternalSstFileTest.PickedLevelBug` to the
main thread.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7754
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D25383808
Pulled By: ltamasi
fbshipit-source-id: 32fb2721e5169ec898d218900bc0d83eead45d03
Summary:
Handle misuse of snprintf return value to avoid Out of bound
read/write.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7686
Test Plan: make check -j64
Reviewed By: riversand963
Differential Revision: D25030831
Pulled By: akankshamahajan15
fbshipit-source-id: 1a1d181c067c78b94d720323ae00b79566b57cfa
Summary:
Added a fix for the failure of
DBTest2.PartitionedIndexUserToInternalKey on ppc64le in travis
Closes https://github.com/facebook/rocksdb/issues/7746
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7752
Test Plan:
Ran travis job multiple times and it passed. Will keep
watching the travis job after this patch.
Reviewed By: pdillinger
Differential Revision: D25373130
Pulled By: akankshamahajan15
fbshipit-source-id: fa0e3f85f75b687415044a506e42cc38ead87975
Summary:
Following https://github.com/facebook/rocksdb/issues/7655 and https://github.com/facebook/rocksdb/issues/7657, this PR adds `full_history_ts_low_` to `ColumnFamilyData`.
`ColumnFamilyData::full_history_ts_low_` will be used to create `FlushJob` and `CompactionJob`.
`ColumnFamilyData::full_history_ts_low` is persisted to the MANIFEST file. An application can only
increase its value. Consider the following case:
>
> The database has a key at ts=950. `full_history_ts_low` is first set to 1000, and then a GC is triggered
> and cleans up all data older than 1000. If the application sets `full_history_ts_low` to 900 afterwards,
> and tries to read at ts=960, the key at 950 is not seen. From the perspective of the read, the result
> is hard to reason. For simplicity, we just do now allow decreasing full_history_ts_low for now.
>
During recovery, the value of `full_history_ts_low` is restored for each column family if applicable. Note that
version edits in the MANIFEST file for the same column family may have `full_history_ts_low` unsorted due
to the potential interleaving of `LogAndApply` calls. Only the max will be used to restore the state of the
column family.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7740
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D25296217
Pulled By: riversand963
fbshipit-source-id: 24acda1df8262cd7cfdc6ce7b0ec56438abe242a
Summary:
The patch adds iterator support to the integrated BlobDB implementation.
Whenever a blob reference is encountered during iteration, the corresponding
blob is retrieved by calling `Version::GetBlob`, assuming the `expose_blob_index`
(formerly `allow_blob`) flag is *not* set. (Note: the flag is set by the old stacked
BlobDB implementation, which has its own blob file handling/blob retrieval logic.)
In addition, `DBIter` now uniformly returns `Status::NotSupported` with the error
message `"BlobDB does not support merge operator."` when encountering a
blob reference while performing a merge (instead of potentially returning a
message that implies the database should be opened using the stacked BlobDB's
`Open`.)
TODO: We can implement support for lazily retrieving the blob value (or in other
words, bypassing the retrieval of blob values based on key) by extending the `Iterator`
API with a new `PrepareValue` method (similarly to `InternalIterator`, which already
supports lazy values).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7731
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D25256293
Pulled By: ltamasi
fbshipit-source-id: c39cd782011495a526cdff99c16f5fca400c4811
