Commit Graph

172 Commits

Author SHA1 Message Date
Yanqin Jin
629e3e1d77 Fix spelling in public API (#9490)
Summary:
I feel it would be nice if we can fix this spelling error.

In `SizeApproximationOptions`, the `include_memtabtles` should be `include_memtables`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9490

Test Plan: make check

Reviewed By: hx235

Differential Revision: D33949862

Pulled By: riversand963

fbshipit-source-id: b2be67501b65d4aabb6b8df1bf25eb8d54cc1466
2022-02-03 15:15:23 -08:00
Yanqin Jin
3122cb4358 Revise APIs related to user-defined timestamp (#8946)
Summary:
ajkr reminded me that we have a rule of not including per-kv related data in `WriteOptions`.
Namely, `WriteOptions` should not include information about "what-to-write", but should just
include information about "how-to-write".

According to this rule, `WriteOptions::timestamp` (experimental) is clearly a violation. Therefore,
this PR removes `WriteOptions::timestamp` for compliance.
After the removal, we need to pass timestamp info via another set of APIs. This PR proposes a set
of overloaded functions `Put(write_opts, key, value, ts)`, `Delete(write_opts, key, ts)`, and
`SingleDelete(write_opts, key, ts)`. Planned to add `Write(write_opts, batch, ts)`, but its complexity
made me reconsider doing it in another PR (maybe).

For better checking and returning error early, we also add a new set of APIs to `WriteBatch` that take
extra `timestamp` information when writing to `WriteBatch`es.
These set of APIs in `WriteBatchWithIndex` are currently not supported, and are on our TODO list.

Removed `WriteBatch::AssignTimestamps()` and renamed `WriteBatch::AssignTimestamp()` to
`WriteBatch::UpdateTimestamps()` since this method require that all keys have space for timestamps
allocated already and multiple timestamps can be updated.

The constructor of `WriteBatch` now takes a fourth argument `default_cf_ts_sz` which is the timestamp
size of the default column family. This will be used to allocate space when calling APIs that do not
specify a column family handle.

Also, updated `DB::Get()`, `DB::MultiGet()`, `DB::NewIterator()`, `DB::NewIterators()` methods, replacing
some assertions about timestamp to returning Status code.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8946

Test Plan:
make check
./db_bench -benchmarks=fillseq,fillrandom,readrandom,readseq,deleterandom -user_timestamp_size=8
./db_stress --user_timestamp_size=8 -nooverwritepercent=0 -test_secondary=0 -secondary_catch_up_one_in=0 -continuous_verification_interval=0

Make sure there is no perf regression by running the following
```
./db_bench_opt -db=/dev/shm/rocksdb -use_existing_db=0 -level0_stop_writes_trigger=256 -level0_slowdown_writes_trigger=256 -level0_file_num_compaction_trigger=256 -disable_wal=1 -duration=10 -benchmarks=fillrandom
```

Before this PR
```
DB path: [/dev/shm/rocksdb]
fillrandom   :       1.831 micros/op 546235 ops/sec;   60.4 MB/s
```
After this PR
```
DB path: [/dev/shm/rocksdb]
fillrandom   :       1.820 micros/op 549404 ops/sec;   60.8 MB/s
```

Reviewed By: ltamasi

Differential Revision: D33721359

Pulled By: riversand963

fbshipit-source-id: c131561534272c120ffb80711d42748d21badf09
2022-02-01 22:19:01 -08:00
Yanqin Jin
d10c5c08d3 Remove iter_start_seqnum and preserve_deletes (#9430)
Summary:
According to https://github.com/facebook/rocksdb/blob/6.27.fb/db/db_impl/db_impl.cc#L2896:L2911 and https://github.com/facebook/rocksdb/blob/6.27.fb/db/db_impl/db_impl_open.cc#L203:L208,
we are going to remove `iter_start_seqnum` and `preserve_deletes` starting from RocksDB 7.0

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9430

Test Plan: make check and CI

Reviewed By: ajkr

Differential Revision: D33753639

Pulled By: riversand963

fbshipit-source-id: c80aab8e8d8fc33e52472fed524ed703d0ffc8b6
2022-01-28 13:28:38 -08:00
Yanqin Jin
b2e53ab2d8 Add checking for DB::DestroyColumnFamilyHandle() (#9347)
Summary:
Closing https://github.com/facebook/rocksdb/issues/5006

Calling `DB::DestroyColumnFamilyHandle(column_family)` with `column_family` being the return value of
`DB::DefaultColumnFamily()` will return `Status::InvalidArgument()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9347

Test Plan: make check

Reviewed By: akankshamahajan15

Differential Revision: D33369675

Pulled By: riversand963

fbshipit-source-id: a8266a4daddf2b7a773c2dc7f3eb9a4adfb6b6dd
2022-01-05 20:26:53 -08:00
slk
2e5f764294 Make IncreaseFullHistoryTsLow to a public API (#9221)
Summary:
As (https://github.com/facebook/rocksdb/issues/9210) discussed, the **full_history_ts_low** is a member of CompactRangeOptions currently, which means a CF's fullHistoryTsLow is advanced only when users submit a CompactRange request.
However, users may want to advance the fllHistoryTsLow without an immediate compact.
This merge make IncreaseFullHistoryTsLow to a public API so users can advance each CF's fullHistoryTsLow seperately.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9221

Reviewed By: akankshamahajan15

Differential Revision: D33201106

Pulled By: riversand963

fbshipit-source-id: 9cb1d013ba93260f72e16353e693ffee167b47ee
2021-12-23 11:03:51 -08:00
Peter Dillinger
0050a73a4f New stable, fixed-length cache keys (#9126)
Summary:
This change standardizes on a new 16-byte cache key format for
block cache (incl compressed and secondary) and persistent cache (but
not table cache and row cache).

The goal is a really fast cache key with practically ideal stability and
uniqueness properties without external dependencies (e.g. from FileSystem).
A fixed key size of 16 bytes should enable future optimizations to the
concurrent hash table for block cache, which is a heavy CPU user /
bottleneck, but there appears to be measurable performance improvement
even with no changes to LRUCache.

This change replaces a lot of disjointed and ugly code handling cache
keys with calls to a simple, clean new internal API (cache_key.h).
(Preserving the old cache key logic under an option would be very ugly
and likely negate the performance gain of the new approach. Complete
replacement carries some inherent risk, but I think that's acceptable
with sufficient analysis and testing.)

The scheme for encoding new cache keys is complicated but explained
in cache_key.cc.

Also: EndianSwapValue is moved to math.h to be next to other bit
operations. (Explains some new include "math.h".) ReverseBits operation
added and unit tests added to hash_test for both.

Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126

Test Plan:
### Basic correctness
Several tests needed updates to work with the new functionality, mostly
because we are no longer relying on filesystem for stable cache keys
so table builders & readers need more context info to agree on cache
keys. This functionality is so core, a huge number of existing tests
exercise the cache key functionality.

### Performance
Create db with
`TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters`
And test performance with
`TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4`
using DEBUG_LEVEL=0 and simultaneous before & after runs.
Before ops/sec, avg over 100 runs: 121924
After ops/sec, avg over 100 runs: 125385 (+2.8%)

### Collision probability
I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity
over many months, by making some pessimistic simplifying assumptions:
* Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys)
* All of every file is cached for its entire lifetime

We use a simple table with skewed address assignment and replacement on address collision
to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output
with `./cache_bench -stress_cache_key -sck_keep_bits=40`:

```
Total cache or DBs size: 32TiB  Writing 925.926 MiB/s or 76.2939TiB/day
Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached)
```

These come from default settings of 2.5M files per day of 32 MB each, and
`-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of
the 128-bit cache key.  With file size of 2\*\*25 contiguous keys (pessimistic), our simulation
is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality.

More default assumptions, relatively pessimistic:
* 100 DBs in same process (doesn't matter much)
* Re-open DB in same process (new session ID related to old session ID) on average
every 100 files generated
* Restart process (all new session IDs unrelated to old) 24 times per day

After enough data, we get a result at the end:

```
(keep 40 bits)  17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected)
```

If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data:

```
(keep 41 bits)  16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected)
(keep 42 bits)  19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected)
```

The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases:

```
197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected)
```

I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data.

Reviewed By: zhichao-cao

Differential Revision: D33171746

Pulled By: pdillinger

fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f
2021-12-16 17:15:13 -08:00
Peter Dillinger
2a67d475f1 Fix bug affecting GetSortedWalFiles, Backups, Checkpoint (#9208)
Summary:
Saw error like this:
`Backup failed -- IO error: No such file or directory: While opening a
file for sequentially reading:
/dev/shm/rocksdb/rocksdb_crashtest_blackbox/004426.log: No such file or
directory`

Unfortunately, GetSortedWalFiles (used by Backups, Checkpoint, etc.)
relies on no file deletions happening while its operating, which
means not only disabling (more) deletions, but ensuring any pending
deletions are completed. Two fixes related to this:

* There was a gap in several places between decrementing
pending_purge_obsolete_files_ and incrementing bg_purge_scheduled_ where
the db mutex would be released and GetSortedWalFiles (and others) could
get false information that no deletions are pending.

* The fix to https://github.com/facebook/rocksdb/issues/8591 (disabling deletions in GetSortedWalFiles) seems
incomplete because it doesn't prevent pending deletions from occuring
during the operation (if deletions not already disabled, the case that
was to be fixed by the change).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9208

Test Plan:
existing tests (it's hard to write a test for interleavings
that are now excluded - this is what stress test is for)

Reviewed By: ajkr

Differential Revision: D32630675

Pulled By: pdillinger

fbshipit-source-id: a121e3da648de130cd24d44c524232f4eb22f178
2021-11-24 14:52:00 -08:00
Jay Zhuang
6cde8d2190 Deprecating iter_start_seqnum and preserve_deletes (#9091)
Summary:
`ReadOptions::iter_start_seqnum` and `DBOptions::preserve_deletes` are
deprecated, please try using user defined timestamp feature instead.
The feature is used to support differential snapshots, but not well
maintained (https://github.com/facebook/rocksdb/issues/6837, https://github.com/facebook/rocksdb/issues/8472) and the interface is not user friendly which
returns an internal key from the iterator. The user defined timestamp
feature is a more flexible feature to support similar usecase, please
switch to that if you have such usecase.
The deprecated feature will be removed in a future release.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9091

Test Plan:
check LOG

Fix https://github.com/facebook/rocksdb/issues/9090

Reviewed By: ajkr

Differential Revision: D32071750

Pulled By: jay-zhuang

fbshipit-source-id: b882c4668dd1bf26ce03c4c192f1bba584bf6104
2021-11-19 16:55:45 -08:00
Yanqin Jin
2035798834 Update TransactionUtil::CheckKeyForConflict to also use timestamps (#9162)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9162

Existing TransactionUtil::CheckKeyForConflict() performs only seq-based
conflict checking. If user-defined timestamp is enabled, it should perform
conflict checking based on timestamps too.

Update TransactionUtil::CheckKey-related methods to verify the timestamp of the
latest version of a key is smaller than the read timestamp. Note that
CheckKeysForConflict() is not updated since it's used only by optimistic
transaction, and we do not plan to update it in this upcoming batch of diffs.

Existing GetLatestSequenceForKey() returns the sequence of the latest
version of a specific user key. Since we support user-defined timestamp, we
need to update this method to also return the timestamp (if enabled) of the
latest version of the key. This will be needed for snapshot validation.

Reviewed By: ltamasi

Differential Revision: D31567960

fbshipit-source-id: 2e4a14aed267435a9aa91bc632d2411c01946d44
2021-11-15 12:52:18 -08:00
Jay Zhuang
29102641dd Skip directory fsync for filesystem btrfs (#8903)
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
   new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
   synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
   to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
   `IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
   forced, the same as above.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903

Test Plan: run tests on btrfs and non btrfs

Reviewed By: ajkr

Differential Revision: D30885059

Pulled By: jay-zhuang

fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
2021-11-03 12:21:27 -07:00
Peter Dillinger
ad5325a736 Experimental support for SST unique IDs (#8990)
Summary:
* New public header unique_id.h and function GetUniqueIdFromTableProperties
which computes a universally unique identifier based on table properties
of table files from recent RocksDB versions.
* Generation of DB session IDs is refactored so that they are
guaranteed unique in the lifetime of a process running RocksDB.
(SemiStructuredUniqueIdGen, new test included.) Along with file numbers,
this enables SST unique IDs to be guaranteed unique among SSTs generated
in a single process, and "better than random" between processes.
See https://github.com/pdillinger/unique_id
* In addition to public API producing 'external' unique IDs, there is a function
for producing 'internal' unique IDs, with functions for converting between the
two. In short, the external ID is "safe" for things people might do with it, and
the internal ID enables more "power user" features for the future. Specifically,
the external ID goes through a hashing layer so that any subset of bits in the
external ID can be used as a hash of the full ID, while also preserving
uniqueness guarantees in the first 128 bits (bijective both on first 128 bits
and on full 192 bits).

Intended follow-up:
* Use the internal unique IDs in cache keys. (Avoid conflicts with https://github.com/facebook/rocksdb/issues/8912) (The file offset can be XORed into
the third 64-bit value of the unique ID.)
* Publish the external unique IDs in FileStorageInfo (https://github.com/facebook/rocksdb/issues/8968)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8990

Test Plan:
Unit tests added, and checking of unique ids in stress test.
NOTE in stress test we do not generate nearly enough files to thoroughly
stress uniqueness, but the test trims off pieces of the ID to check for
uniqueness so that we can infer (with some assumptions) stronger
properties in the aggregate.

Reviewed By: zhichao-cao, mrambacher

Differential Revision: D31582865

Pulled By: pdillinger

fbshipit-source-id: 1f620c4c86af9abe2a8d177b9ccf2ad2b9f48243
2021-10-18 23:32:01 -07:00
Jay Zhuang
314de7e7de Make DB::Close() thread-safe (#8970)
Summary:
If `DB::Close()` is called in multi-thread env, the resource
could be double released, which causes exception or assert.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8970

Test Plan:
Test with multi-thread benchmark, with each thread try to
close the DB at the end.

Reviewed By: pdillinger

Differential Revision: D31242042

Pulled By: jay-zhuang

fbshipit-source-id: a61276b1b61e07732e375554106946aea86a23eb
2021-10-18 20:32:35 -07:00
Peter Dillinger
3ffb3baa0b Add (Live)FileStorageInfo API (#8968)
Summary:
New classes FileStorageInfo and LiveFileStorageInfo and
'experimental' function DB::GetLiveFilesStorageInfo, which is intended
to largely replace several fragmented DB functions needed to create
checkpoints and backups.

This function is now used to create checkpoints and backups, because
it fixes many (probably not all) of the prior complexities of checkpoint
not having atomic access to DB metadata. This also ensures strong
functional test coverage of the new API. Specifically, much of the old
CheckpointImpl::CreateCustomCheckpoint has been migrated to and
updated in DBImpl::GetLiveFilesStorageInfo, with the former now
calling the latter.

Also, the class FileStorageInfo in metadata.h compatibly replaces
BackupFileInfo and serves as a new base class for SstFileMetaData.
Some old fields of SstFileMetaData are still provided (for now) but
deprecated.

Although FileStorageInfo::directory is accurate when using db_paths
and/or cf_paths, these have never been supported by Checkpoint
nor BackupEngine and still are not. This change does now detect
these cases and return NotSupported when appropriate. (More work
needed for support.)

Somehow this change broke ProgressCallbackDuringBackup, but
the progress_callback logic was dubious to begin with because it
would call the callback based on copy buffer size, not size actually
copied. Logic and test updated to track size actually copied
per-thread.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8968

Test Plan:
tests updated.
DB::GetLiveFilesStorageInfo mostly tested by use in CheckpointImpl.
DBTest.SnapshotFiles updated to also test GetLiveFilesStorageInfo,
including reading the data after DB close.
Added CheckpointTest.CheckpointWithDbPath (NotSupported).

Reviewed By: siying

Differential Revision: D31242045

Pulled By: pdillinger

fbshipit-source-id: b183d1ce9799e220daaefd6b3b5365d98de676c0
2021-10-16 10:04:32 -07:00
Giuseppe Ottaviano
4bfd415e34 Fix sequence number bump logic in multi-CF SST ingestion (#9005)
Summary:
The code in `IngestExternalFiles()` that bumps the DB's sequence number
depending on what seqnos were assigned to the files has 3 bugs:

1) There is an assertion that the sequence number is increased in all the
affected column families, but this is unnecessary, it is fine if some files can
stick to a lower sequence number. It is very easy to hit the assertion: it is
sufficient to insert 2 files in 2 CFs, one which overlaps the CF and one that
doesn't (for example the CF is empty). The line added in the
`IngestFilesIntoMultipleColumnFamilies_Success` test makes the assertion fail.

2) SetLastSequence() is called with the sum of all the bumps across CFs, but we
should take the maximum instead, as all CFs start with the current seqno and bump
it independently.

3) The code above is accidentally under a `#ifndef NDEBUG`, so it doesn't run in
optimized builds, so some files may be assigned seqnos from the future.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9005

Test Plan:
Added line in `IngestFilesIntoMultipleColumnFamilies_Success` that
triggers the assertion, verified that the test (and all the others) pass after
the fix.

Reviewed By: ajkr

Differential Revision: D31597892

Pulled By: ot

fbshipit-source-id: c2d3237f90290df1178736ace8653a9623f5a770
2021-10-12 20:39:52 -07:00
Zhichao Cao
bcd049cd2d Ingest external SST files with Temperature hints (#8949)
Summary:
Add the file temperature to `IngestExternalFileArg` such that when SST files are ingested, user is able to assign the temperature to each SST file. If the temperature vector is empty or its size does not match the file name vector size, all ingested SST files will be assigned with `Temperature::unKnown`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8949

Test Plan: add the new test and make check

Reviewed By: siying

Differential Revision: D31127852

Pulled By: zhichao-cao

fbshipit-source-id: 141a81f0f7b473d88f4ab0cb2a21a114cbc6f83c
2021-10-08 10:32:24 -07:00
anand76
532ff334d9 Don't ignore deletion rate limit if WAL dir is different (#8967)
Summary:
If WAL dir is different from the DB dir, we should still honor the SstFileManager deletion rate limit for SST files.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8967

Test Plan: Add a new unit test in db_sst_test

Reviewed By: pdillinger

Differential Revision: D31220116

Pulled By: anand1976

fbshipit-source-id: bcde8a53a7d728e15e597fb5d07ee86c1b38bd28
2021-09-30 13:26:31 -07:00
Yanqin Jin
b512f4bc76 Batch blob read IO for MultiGet (#8699)
Summary:
In batched `MultiGet()`, RocksDB batches blob read IO and uses `RandomAccessFileReader::MultiRead()`
to read the blobs instead of issuing multiple `Read()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8699

Test Plan:
```
make check
```

Reviewed By: ltamasi

Differential Revision: D31030861

Pulled By: riversand963

fbshipit-source-id: a0df6060cbfd54cff9515a4eee08807b1dbcb0c8
2021-09-17 19:23:13 -07:00
Akanksha Mahajan
d6aa8c49f8 Expose blob file information through the EventListener interface (#8675)
Summary:
1. Extend FlushJobInfo and CompactionJobInfo with information about the blob files generated by flush/compaction jobs. This PR add two structures BlobFileInfo and BlobFileGarbageInfo that contains the required information of blob files.
 2. Notify the creation and deletion of blob files through OnBlobFileCreationStarted, OnBlobFileCreated, and OnBlobFileDeleted.
 3. Test OnFile*Finish operations notifications with Blob Files.
 4. Log the blob file creation/deletion events through EventLogger in Log file.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8675

Test Plan: Add new unit tests in listener_test

Reviewed By: ltamasi

Differential Revision: D30412613

Pulled By: akankshamahajan15

fbshipit-source-id: ca51b63c6e8c8d0485a38c503572bc5a82bd5d07
2021-09-16 17:23:36 -07:00
mrambacher
beed86473a Make MemTableRepFactory into a Customizable class (#8419)
Summary:
This PR does the following:
-> Makes the MemTableRepFactory into a Customizable class and creatable/configurable via CreateFromString
-> Makes the existing implementations compatible with configurations
-> Moves the "SpecialRepFactory" test class into testutil, accessible via the ObjectRegistry or a NewSpecial API

New tests were added to validate the functionality and all existing tests pass.  db_bench and memtablerep_bench were hand-tested to verify the functionality in those tools.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8419

Reviewed By: zhichao-cao

Differential Revision: D29558961

Pulled By: mrambacher

fbshipit-source-id: 81b7229636e4e649a0c914e73ac7b0f8454c931c
2021-09-08 07:46:44 -07:00
Andrew Kryczka
941543721d Bytes read stat for VerifyChecksum() and VerifyFileChecksums() APIs (#8741)
Summary:
- Clarified some comments on compatibility for adding new ticker stats
- Added read I/O stats for `VerifyChecksum()` and `VerifyFileChecksums()` APIs

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8741

Test Plan: new unit test

Reviewed By: zhichao-cao

Differential Revision: D30708578

Pulled By: ajkr

fbshipit-source-id: d06b961f7e199ae92c266b683e39870aa8f63449
2021-09-07 13:28:29 -07:00
Peter Dillinger
4750421ece Replace most typedef with using= (#8751)
Summary:
Old typedef syntax is confusing

Most but not all changes with

    perl -pi -e 's/typedef (.*) ([a-zA-Z0-9_]+);/using $2 = $1;/g' list_of_files
    make format

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8751

Test Plan: existing

Reviewed By: zhichao-cao

Differential Revision: D30745277

Pulled By: pdillinger

fbshipit-source-id: 6f65f0631c3563382d43347896020413cc2366d9
2021-09-07 11:31:59 -07:00
Peter Dillinger
13ded69484 Built-in support for generating unique IDs, bug fix (#8708)
Summary:
Env::GenerateUniqueId() works fine on Windows and on POSIX
where /proc/sys/kernel/random/uuid exists. Our other implementation is
flawed and easily produces collision in a new multi-threaded test.
As we rely more heavily on DB session ID uniqueness, this becomes a
serious issue.

This change combines several individually suitable entropy sources
for reliable generation of random unique IDs, with goal of uniqueness
and portability, not cryptographic strength nor maximum speed.

Specifically:
* Moves code for getting UUIDs from the OS to port::GenerateRfcUuid
rather than in Env implementation details. Callers are now told whether
the operation fails or succeeds.
* Adds an internal API GenerateRawUniqueId for generating high-quality
128-bit unique identifiers, by combining entropy from three "tracks":
  * Lots of info from default Env like time, process id, and hostname.
  * std::random_device
  * port::GenerateRfcUuid (when working)
* Built-in implementations of Env::GenerateUniqueId() will now always
produce an RFC 4122 UUID string, either from platform-specific API or
by converting the output of GenerateRawUniqueId.

DB session IDs now use GenerateRawUniqueId while DB IDs (not as
critical) try to use port::GenerateRfcUuid but fall back on
GenerateRawUniqueId with conversion to an RFC 4122 UUID.

GenerateRawUniqueId is declared and defined under env/ rather than util/
or even port/ because of the Env dependency.

Likely follow-up: enhance GenerateRawUniqueId to be faster after the
first call and to guarantee uniqueness within the lifetime of a single
process (imparting the same property onto DB session IDs).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8708

Test Plan:
A new mini-stress test in env_test checks the various public
and internal APIs for uniqueness, including each track of
GenerateRawUniqueId individually. We can't hope to verify anywhere close
to 128 bits of entropy, but it can at least detect flaws as bad as the
old code. Serial execution of the new tests takes about 350 ms on
my machine.

Reviewed By: zhichao-cao, mrambacher

Differential Revision: D30563780

Pulled By: pdillinger

fbshipit-source-id: de4c9ff4b2f581cf784fcedb5f39f16e5185c364
2021-08-30 15:20:41 -07:00
anand76
ebaa3c8a59 Fix a race condition in DumpStats() during iteration of the ColumnFamilySet (#8714)
Summary:
DumpStats() iterates through the ColumnFamilySet. There is a potential
race condition because it does Ref the cfd, and the cfd could get
destroyed during the iteration.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8714

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D30580199

Pulled By: anand1976

fbshipit-source-id: 60a3443ad0d4f7ac6a977dec780e6d2c1b70b850
2021-08-26 15:40:26 -07:00
Peter Dillinger
b6269b078a Stable cache keys on ingested SST files (#8669)
Summary:
Extends https://github.com/facebook/rocksdb/issues/8659 to work for ingested external SST files, even
the same file ingested into different DBs sharing a block cache.

Note: These new cache keys are currently only enabled when FileSystem
does not provide GetUniqueId. For now, they are typically larger,
so slightly less efficient.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8669

Test Plan: Extended unit test

Reviewed By: zhichao-cao

Differential Revision: D30398532

Pulled By: pdillinger

fbshipit-source-id: 1f13e2af4b8bfff5741953a69466e9589fbc23c7
2021-08-18 11:33:03 -07:00
Adam Retter
5de333fd99 Add db_test2 to to ASSERT_STATUS_CHECKED (#8640)
Summary:
This is the `db_test2` parts of https://github.com/facebook/rocksdb/pull/7737 reworked on the latest HEAD.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8640

Reviewed By: akankshamahajan15

Differential Revision: D30303684

Pulled By: mrambacher

fbshipit-source-id: 263e2f82d849bde4048b60aed8b31e7deed4706a
2021-08-16 08:10:32 -07:00
Merlin Mao
f58d276764 Make TraceRecord and Replayer public (#8611)
Summary:
New public interfaces:
`TraceRecord` and `TraceRecord::Handler`, available in "rocksdb/trace_record.h".
`Replayer`, available in `rocksdb/utilities/replayer.h`.

User can use `DB::NewDefaultReplayer()` to create a Replayer to auto/manual replay a trace file.

Unit tests:
- `./db_test2 --gtest_filter="DBTest2.TraceAndReplay"`: Updated with the internal API changes.
- `./db_test2 --gtest_filter="DBTest2.TraceAndManualReplay"`: New for manual replay.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8611

Reviewed By: ajkr

Differential Revision: D30266329

Pulled By: autopear

fbshipit-source-id: 1ecb3cbbedae0f6a67c18f0cc82e002b4d81b6f8
2021-08-11 19:32:46 -07:00
Baptiste Lemaire
e3a96c4823 Memtable sampling for mempurge heuristic. (#8628)
Summary:
Changes the API of the MemPurge process: the `bool experimental_allow_mempurge` and `experimental_mempurge_policy` flags have been replaced by a `double experimental_mempurge_threshold` option.
This change of API reflects another major change introduced in this PR: the MemPurgeDecider() function now works by sampling the memtables being flushed to estimate the overall amount of useful payload (payload minus the garbage), and then compare this useful payload estimate with the `double experimental_mempurge_threshold` value.
Therefore, when the value of this flag is `0.0` (default value), mempurge is simply deactivated. On the other hand, a value of `DBL_MAX` would be equivalent to always going through a mempurge regardless of the garbage ratio estimate.
At the moment, a `double experimental_mempurge_threshold` value else than 0.0 or `DBL_MAX` is opnly supported`with the `SkipList` memtable representation.
Regarding the sampling, this PR includes the introduction of a `MemTable::UniqueRandomSample` function that collects (approximately) random entries from the memtable by using the new `SkipList::Iterator::RandomSeek()` under the hood, or by iterating through each memtable entry, depending on the target sample size and the total number of entries.
The unit tests have been readapted to support this new API.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8628

Reviewed By: pdillinger

Differential Revision: D30149315

Pulled By: bjlemaire

fbshipit-source-id: 1feef5390c95db6f4480ab4434716533d3947f27
2021-08-10 18:09:03 -07:00
Levi Tamasi
87882736ef Fix the sorting of KeyContexts for batched MultiGet (#8633)
Summary:
`CompareKeyContext::operator()` on the trunk has a bug: when comparing
column family IDs, `lhs` is used for both sides of the comparison. This
results in the `KeyContext`s getting sorted solely based on key, which
in turn means that keys with the same column family do not necessarily
form a single range in the sorted list. This violates an assumption of the
batched `MultiGet` logic, leading to the same column family
showing up multiple times in the list of `MultiGetColumnFamilyData`.
The end result is the code attempting to check out the thread-local
`SuperVersion` for the same CF multiple times, causing an
assertion violation in debug builds and memory corruption/crash in
release builds.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8633

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D30169182

Pulled By: ltamasi

fbshipit-source-id: a47710652df7e95b14b40fb710924c11a8478023
2021-08-06 16:27:42 -07:00
mrambacher
ab7f7c9e49 Allow WAL dir to change with db dir (#8582)
Summary:
Prior to this change, the "wal_dir"  DBOption would always be set (defaults to dbname) when the DBOptions were sanitized.  Because of this setitng in the options file, it was not possible to rename/relocate a database directory after it had been created and use the existing options file.

After this change, the "wal_dir" option is only set under specific circumstances.  Methods were added to the ImmutableDBOptions class to see if it is set and if it is set to something other than the dbname.  Additionally, a method was added to retrieve the effective value of the WAL dir (either the option or the dbname/path).

Tests were added to the core and ldb to test that a database could be created and renamed without issue.  Additional tests for various permutations of wal_dir were also added.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8582

Reviewed By: pdillinger, autopear

Differential Revision: D29881122

Pulled By: mrambacher

fbshipit-source-id: 67d3d033dc8813d59917b0a3fba2550c0efd6dfb
2021-07-30 12:16:44 -07:00
Peter Dillinger
1d34cd797e Fix insecure internal API for GetImpl (#8590)
Summary:
Calling the GetImpl function could leave reference to a local
callback function in a field of a parameter struct. As this is
performance-critical code, I'm not going to attempt to sanitize this
code too much, but make the existing hack a bit cleaner by reverting
what it overwrites in the input struct.

Added SaveAndRestore utility class to make that easier.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8590

Test Plan:
added unit test for SaveAndRestore; existing tests for
GetImpl

Reviewed By: riversand963

Differential Revision: D29947983

Pulled By: pdillinger

fbshipit-source-id: 2f608853f970bc06724e834cc84dcc4b8599ddeb
2021-07-29 17:23:01 -07:00
Jay Zhuang
42eaa45c1b Avoid updating option if there's no value updated (#8518)
Summary:
Try avoid expensive updating options operation if
`SetDBOptions()` does not change any option value.
Skip updating is not guaranteed, for example, changing `bytes_per_sync`
to `0` may still trigger updating, as the value could be sanitized.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8518

Test Plan: added unittest

Reviewed By: riversand963

Differential Revision: D29672639

Pulled By: jay-zhuang

fbshipit-source-id: b7931de62ceea6f1bdff0d1209adf1197d3ed1f4
2021-07-21 13:45:59 -07:00
Peter Dillinger
df5dc73bec Don't hold DB mutex for block cache entry stat scans (#8538)
Summary:
I previously didn't notice the DB mutex was being held during
block cache entry stat scans, probably because I primarily checked for
read performance regressions, because they require the block cache and
are traditionally latency-sensitive.

This change does some refactoring to avoid holding DB mutex and to
avoid triggering and waiting for a scan in GetProperty("rocksdb.cfstats").
Some tests have to be updated because now the stats collector is
populated in the Cache aggressively on DB startup rather than lazily.
(I hope to clean up some of this added complexity in the future.)

This change also ensures proper treatment of need_out_of_mutex for
non-int DB properties.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8538

Test Plan:
Added unit test logic that uses sync points to fail if the DB mutex
is held during a scan, covering the various ways that a scan might be
triggered.

Performance test - the known impact to holding the DB mutex is on
TransactionDB, and the easiest way to see the impact is to hack the
scan code to almost always miss and take an artificially long time
scanning. Here I've injected an unconditional 5s sleep at the call to
ApplyToAllEntries.

Before (hacked):

    $ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     433.219 micros/op 2308 ops/sec;    0.1 MB/s ( transactions:78999 aborts:0)
    rocksdb.db.write.micros P50 : 16.135883 P95 : 36.622503 P99 : 66.036115 P100 : 5000614.000000 COUNT : 149677 SUM : 8364856
    $ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     448.802 micros/op 2228 ops/sec;    0.1 MB/s ( transactions:75999 aborts:0)
    rocksdb.db.write.micros P50 : 16.629221 P95 : 37.320607 P99 : 72.144341 P100 : 5000871.000000 COUNT : 143995 SUM : 13472323

Notice the 5s P100 write time.

After (hacked):

    $ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     303.645 micros/op 3293 ops/sec;    0.1 MB/s ( transactions:98999 aborts:0)
    rocksdb.db.write.micros P50 : 16.061871 P95 : 33.978834 P99 : 60.018017 P100 : 616315.000000 COUNT : 187619 SUM : 4097407
    $ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     310.383 micros/op 3221 ops/sec;    0.1 MB/s ( transactions:96999 aborts:0)
    rocksdb.db.write.micros P50 : 16.270026 P95 : 35.786844 P99 : 64.302878 P100 : 603088.000000 COUNT : 183819 SUM : 4095918

P100 write is now ~0.6s. Not good, but it's the same even if I completely bypass all the scanning code:

    $ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     311.365 micros/op 3211 ops/sec;    0.1 MB/s ( transactions:96999 aborts:0)
    rocksdb.db.write.micros P50 : 16.274362 P95 : 36.221184 P99 : 68.809783 P100 : 649808.000000 COUNT : 183819 SUM : 4156767
    $ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op'
    randomtransaction :     308.395 micros/op 3242 ops/sec;    0.1 MB/s ( transactions:97999 aborts:0)
    rocksdb.db.write.micros P50 : 16.106222 P95 : 37.202403 P99 : 67.081875 P100 : 598091.000000 COUNT : 185714 SUM : 4098832

No substantial difference.

Reviewed By: siying

Differential Revision: D29738847

Pulled By: pdillinger

fbshipit-source-id: 1c5c155f5a1b62e4fea0fd4eeb515a8b7474027b
2021-07-16 14:13:08 -07:00
Baptiste Lemaire
837705ad80 Make mempurge a background process (equivalent to in-memory compaction). (#8505)
Summary:
In https://github.com/facebook/rocksdb/issues/8454, I introduced a new process baptized `MemPurge` (memtable garbage collection). This new PR is built upon this past mempurge prototype.
In this PR, I made the `mempurge` process a background task, which provides superior performance since the mempurge process does not cling on the db_mutex anymore, and addresses severe restrictions from the past iteration (including a scenario where the past mempurge was failling, when a memtable was mempurged but was still referred to by an iterator/snapshot/...).
Now the mempurge process ressembles an in-memory compaction process: the stack of immutable memtables is filtered out, and the useful payload is used to populate an output memtable. If the output memtable is filled at more than 60% capacity (arbitrary heuristic) the mempurge process is aborted and a regular flush process takes place, else the output memtable is kept in the immutable memtable stack. Note that adding this output memtable to the `imm()` memtable stack does not trigger another flush process, so that the flush thread can go to sleep at the end of a successful mempurge.
MemPurge is activated by making the `experimental_allow_mempurge` flag `true`. When activated, the `MemPurge` process will always happen when the flush reason is `kWriteBufferFull`.
The 3 unit tests confirm that this process supports `Put`, `Get`, `Delete`, `DeleteRange` operators and is compatible with `Iterators` and `CompactionFilters`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8505

Reviewed By: pdillinger

Differential Revision: D29619283

Pulled By: bjlemaire

fbshipit-source-id: 8a99bee76b63a8211bff1a00e0ae32360aaece95
2021-07-09 17:23:59 -07:00
mrambacher
be219089ad Add BlobMetaData retrieval methods (#8273)
Summary:
Added BlobMetaData to ColumnFamilyMetaData and LiveBlobMetaData and DB API GetLiveBlobMetaData to retrieve it.

First pass at struct.  More tests and maybe fields to come...

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8273

Reviewed By: ltamasi

Differential Revision: D29102400

Pulled By: mrambacher

fbshipit-source-id: 8a2383a4446328be6b91dced9841fdd3dfc80b73
2021-06-28 08:13:29 -07:00
Jay Zhuang
54d73d6429 Fix DeleteFilesInRange may cause inconsistent compaction error (#8434)
Summary:
`DeleteFilesInRange()` marks deleting files to `being_compacted`
before deleting, which may cause ongoing compactions report corruption
exception or ASSERT for debug build.

Adding the missing `ComputeCompactionScore()` when `being_compacted` is set.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8434

Test Plan: Unittest

Reviewed By: ajkr

Differential Revision: D29276127

Pulled By: jay-zhuang

fbshipit-source-id: f5b223e3c1fc6d821e100e3f3442bc70c1d50cf7
2021-06-22 09:17:37 -07:00
Zhichao Cao
82a70e1470 Trace MultiGet Keys and CF_IDs to the trace file (#8421)
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
2021-06-18 15:04:05 -07:00
Peter Dillinger
b3dbeadc34 Fix double-dumping CF stats to log (#8380)
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
2021-06-11 17:06:09 -07:00
Zhichao Cao
f44e69c64a Use DbSessionId as cache key prefix when secondary cache is enabled (#8360)
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
2021-06-10 11:02:43 -07:00
mrambacher
8948dc8524 Make ImmutableOptions struct that inherits from ImmutableCFOptions and ImmutableDBOptions (#8262)
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
2021-05-05 14:00:17 -07:00
mrambacher
01e460d538 Make types of Immutable/Mutable Options fields match that of the underlying Option (#8176)
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
2021-04-22 20:43:54 -07:00
Jay Zhuang
f0fca2b1d5 Add internal compaction API for Secondary instance (#8171)
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
2021-04-22 13:02:28 -07:00
Akanksha Mahajan
596e9008e4 Stall writes in WriteBufferManager when memory_usage exceeds buffer_size (#7898)
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
2021-04-21 13:54:02 -07:00
Peter Dillinger
879357fdb0 Make backups openable as read-only DBs (#8142)
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
2021-04-06 14:37:53 -07:00
Akanksha Mahajan
689b13e639 Add request_id in IODebugContext. (#8045)
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
2021-04-01 13:14:51 -07:00
sherriiiliu
e6534900bd Fix possible hang issue in ~DBImpl() when flush is scheduled in LOW pool (#8125)
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
2021-03-30 18:35:20 -07:00
Akanksha Mahajan
27d57a035e Use SST file manager to track blob files as well (#8037)
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
2021-03-17 20:44:49 -07:00
mrambacher
3dff28cf9b Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033)
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
2021-03-15 04:34:11 -07:00
Akanksha Mahajan
46cf5fbfdd Extend VerifyFileChecksums API for blob files (#7979)
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
2021-02-22 22:09:22 -08:00
Zhichao Cao
b0fd1cc45a Introduce a new trace file format (v 0.2) for better extension (#7977)
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
2021-02-18 23:05:35 -08:00
Jay Zhuang
59ba104e4a Fix txn MultiGet() return un-committed data with snapshot (#7963)
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
2021-02-18 08:49:00 -08:00