Commit Graph

113 Commits

Author SHA1 Message Date
Yanqin Jin
d263505417 Avoid div-by-zero error in db_stress (#9086)
Summary:
If a column family has 0 levels, then existing `TestCompactFiles(...)` may hit
divide-by-zero. To fix, return early if the cf is empty.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9086

Test Plan: TBD

Reviewed By: ajkr

Differential Revision: D31986799

Pulled By: riversand963

fbshipit-source-id: 48f7dfb2b2b47cfc1315cb71ca80eb230d947f17
2021-10-31 22:16:03 -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
Levi Tamasi
3e1bf771a3 Make it possible to force the garbage collection of the oldest blob files (#8994)
Summary:
The current BlobDB garbage collection logic works by relocating the valid
blobs from the oldest blob files as they are encountered during compaction,
and cleaning up blob files once they contain nothing but garbage. However,
with sufficiently skewed workloads, it is theoretically possible to end up in a
situation when few or no compactions get scheduled for the SST files that contain
references to the oldest blob files, which can lead to increased space amp due
to the lack of GC.

In order to efficiently handle such workloads, the patch adds a new BlobDB
configuration option called `blob_garbage_collection_force_threshold`,
which signals to BlobDB to schedule targeted compactions for the SST files
that keep alive the oldest batch of blob files if the overall ratio of garbage in
the given blob files meets the threshold *and* all the given blob files are
eligible for GC based on `blob_garbage_collection_age_cutoff`. (For example,
if the new option is set to 0.9, targeted compactions will get scheduled if the
sum of garbage bytes meets or exceeds 90% of the sum of total bytes in the
oldest blob files, assuming all affected blob files are below the age-based cutoff.)
The net result of these targeted compactions is that the valid blobs in the oldest
blob files are relocated and the oldest blob files themselves cleaned up (since
*all* SST files that rely on them get compacted away).

These targeted compactions are similar to periodic compactions in the sense
that they force certain SST files that otherwise would not get picked up to undergo
compaction and also in the sense that instead of merging files from multiple levels,
they target a single file. (Note: such compactions might still include neighboring files
from the same level due to the need of having a "clean cut" boundary but they never
include any files from any other level.)

This functionality is currently only supported with the leveled compaction style
and is inactive by default (since the default value is set to 1.0, i.e. 100%).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8994

Test Plan: Ran `make check` and tested using `db_bench` and the stress/crash tests.

Reviewed By: riversand963

Differential Revision: D31489850

Pulled By: ltamasi

fbshipit-source-id: 44057d511726a0e2a03c5d9313d7511b3f0c4eab
2021-10-11 18:03:01 -07:00
Akanksha Mahajan
84d71f30c4 Enable SingleDelete with user defined ts in db_bench and crash tests (#8971)
Summary:
Enable SingleDelete with user defined timestamp in db_bench,
db_stress and crash test

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8971

Test Plan:
1. For db_stress, ran the command for full duration: i) python3 -u tools/db_crashtest.py
--enable_ts whitebox --nooverwritepercent=100
ii) make crash_test_with_ts

2. For db_bench, ran:  ./db_bench -benchmarks=randomreplacekeys
-user_timestamp_size=8 -use_single_deletes=true

Reviewed By: riversand963

Differential Revision: D31246558

Pulled By: akankshamahajan15

fbshipit-source-id: 29cd8740c9921341e52f09242fca3c44d75a12b7
2021-10-01 16:48:01 -07:00
mrambacher
13ae16c315 Cleanup includes in dbformat.h (#8930)
Summary:
This header file was including everything and the kitchen sink when it did not need to.  This resulted in many places including this header when they needed other pieces instead.

Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing.

Hopefully, this sort of code hygiene cleanup will speed up the builds...

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930

Reviewed By: pdillinger

Differential Revision: D31142788

Pulled By: mrambacher

fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d
2021-09-29 04:04:40 -07:00
Andrew Kryczka
5c92aa38ea Avoid overwriting first non-OK Status in db_stress setup (#8907)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8907

Reviewed By: zhichao-cao

Differential Revision: D30922081

Pulled By: ajkr

fbshipit-source-id: ad7a32c21d0049342fd20c9b7f555e93674c3671
2021-09-15 14:28:09 -07:00
Peter Dillinger
c9cd5d25a8 Remove some unneeded code (#8736)
Summary:
* FullKey and ParseFullKey appear to serve no purpose in the public API
(or anything else) so removed. Only use in one test updated.
* NumberToString serves no purpose vs. ToString so removed, numerous
calls updated
* Remove unnecessary forward declarations in metadata.h by re-arranging
class definitions.
* Remove some unneeded semicolons

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8736

Test Plan: existing tests

Reviewed By: mrambacher

Differential Revision: D30700039

Pulled By: pdillinger

fbshipit-source-id: 1e436a576f511a6ed8b4d97af7cc8216bc729af2
2021-09-01 14:28:58 -07:00
Peter Dillinger
2a383f21f4 Add Bloom/Ribbon hybrid API support (#8679)
Summary:
This is essentially resurrection and fixing of the part of
https://github.com/facebook/rocksdb/issues/8198 that was reverted in https://github.com/facebook/rocksdb/issues/8212, using data added in https://github.com/facebook/rocksdb/issues/8246. Basically,
when configuring Ribbon filter, you can specify an LSM level before which
Bloom will be used instead of Ribbon. But Bloom is only considered for
Leveled and Universal compaction styles and file going into a known LSM
level. This way, SST file writer, FIFO compaction, etc. use Ribbon filter as
you would expect with NewRibbonFilterPolicy.

So that this can be controlled with a single int value and so that flushes
can be distinguished from intra-L0, we consider flush to go to level -1 for
the purposes of this option. (Explained in API comment.)

I also expect the most common and recommended Ribbon configuration to
use Bloom during flush, to minimize slowing down writes and because according
to my estimates, Ribbon only pays off if the structure lives in memory for
more than an hour. Thus, I have changed the default for NewRibbonFilterPolicy
to be this mild hybrid configuration. I don't really want to add something like
NewHybridFilterPolicy because at least the mild hybrid configuration (Bloom for
flush, Ribbon otherwise) should be considered a natural choice.

C APIs also updated, but because they don't support overloading,
rocksdb_filterpolicy_create_ribbon is kept pure ribbon for clarity and
rocksdb_filterpolicy_create_ribbon_hybrid must be called for a hybrid
configuration. While touching C API, I changed bits per key options from
int to double.

BuiltinFilterPolicy is needed so that LevelThresholdFilterPolicy doesn't inherit
unused fields from BloomFilterPolicy.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8679

Test Plan: new + updated tests, including crash test

Reviewed By: jay-zhuang

Differential Revision: D30445797

Pulled By: pdillinger

fbshipit-source-id: 6f5aeddfd6d79f7e55493b563c2d1d2d568892e1
2021-08-20 18:00:16 -07:00
Jay Zhuang
0729b287e9 Exclude property kLiveSstFilesSizeAtTemperature from stress_test (#8668)
Summary:
Just like other per_level properties.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8668

Test Plan: stress_test

Reviewed By: zhichao-cao

Differential Revision: D30360967

Pulled By: jay-zhuang

fbshipit-source-id: 70da2557b95c55e8081b04ebf1a909a0fe69488f
2021-08-17 09:06:01 -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
Akanksha Mahajan
052c24a668 Fix db_stress failure (#8632)
Summary:
FaultInjectionTestFS injects error in Rename operation. Because
of injected error, info.log fails to be created if rename  returns error and info_log is set to nullptr which leads to this assertion

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8632

Test Plan: run the db_stress job locally

Reviewed By: ajkr

Differential Revision: D30167387

Pulled By: akankshamahajan15

fbshipit-source-id: 8d08c4c33e8f0cabd368bbb498d21b9de0660067
2021-08-07 09:21:03 -07:00
Baptiste Lemaire
d6006f9c9b Add experimental mempurge policy flag to db_stress. (#8588)
Summary:
Add `experimental_mempurge_policy` flag to `db_stress` and `db_crashtest.py`.
This flag is only read if the `experimental_allow_mempurge` flag is set to `true`. This flag can take the following values: `kAlways`, and `kAlternate` (default).
- `kAlways`: a flush is always redirected to a mempurge. If the mempurge aborts, the a regular flush proceeds.
- `kAlternate`: if one or more of the flush input memtables is an mempurge output memtable, then a flush is performed, else a mempurge is carried out. Similar to kAlways, if a mempurge aborts, the FlushJob proceeds to a regular flush to storage.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8588

Reviewed By: pdillinger

Differential Revision: D29934251

Pulled By: bjlemaire

fbshipit-source-id: 90c1debed2029b9915d066914556547507c33dae
2021-07-28 13:27:58 -07:00
sdong
9b41082d4a Complete the fix of stress open WAL drop fix (#8570)
Summary:
https://github.com/facebook/rocksdb/pull/8548 is not complete. We should instead cover all cases writable files are buffered, not just when failures are ingested. Extend it to any case where failures are ingested in DB open.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8570

Test Plan: Run db_stress and see it doesn't break

Reviewed By: jay-zhuang

Differential Revision: D29830415

fbshipit-source-id: 94449a0468fb2f7eec17423724008c9c63b2445d
2021-07-21 16:08:53 -07:00
Jay Zhuang
66ca5ac427 Cleanup cf handlers before deleting db (#8564)
Summary:
Delete column family handlers before deleting db to avoid `last_ref`
assert.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8564

Test Plan: Inject compaction test in db_stress test

Reviewed By: pdillinger

Differential Revision: D29797375

Pulled By: jay-zhuang

fbshipit-source-id: e8baf4d279f4db5d963db95c9445454156205501
2021-07-20 14:59:40 -07:00
Peter Dillinger
d5f3b77f23 Add GetMapProperty to db_stress (#8551)
Summary:
Already has good coverage for GetProperty and GetIntProperty
but this one was missing.

This should add more confidence to https://github.com/facebook/rocksdb/issues/8538

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8551

Test Plan:
brief local run with boosted probability showed no immediate
issues

Reviewed By: siying

Differential Revision: D29746383

Pulled By: pdillinger

fbshipit-source-id: 9f9f525bc1a7607f85e563e33bda1979ef197127
2021-07-19 08:10:29 -07:00
sdong
39a07c9651 DB Stress Reopen write failure to skip WAL (#8548)
Summary:
When DB Stress enables write failure in reopen, WAL files are also created with a wrapper writalbe file which buffers write until fsync. However, crash test currently expects all writes to WAL is persistent. This is at odd with the unsynced bytes dropped. To work it around temporarily, we disable WAL write failure for now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8548

Test Plan: Run db_stress. Manual printf to make sure only WAL files are skipped.

Reviewed By: jay-zhuang

Differential Revision: D29745095

fbshipit-source-id: 1879dd2c01abad7879ca243ee94570ec47c347f3
2021-07-16 16:09:33 -07:00
Baptiste Lemaire
0229a88dfe Crashtest mempurge (#8545)
Summary:
Add `experiemental_allow_mempurge` flag support for `db_stress` and `db_crashtest.py`, with a `false` default value.
I succesfully tested locally both `whitebox` and `blackbox` crash tests with `experiemental_allow_mempurge` flag set as true.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8545

Reviewed By: akankshamahajan15

Differential Revision: D29734513

Pulled By: bjlemaire

fbshipit-source-id: 24316c0eccf6caf409e95c035f31d822c66714ae
2021-07-16 10:20:22 -07:00
sdong
b1a53db327 FaultInjectionTestFS::DeleteFilesCreatedAfterLastDirSync() to recover… (#8501)
Summary:
… small overwritten files.
If a file is overwritten with renamed and the parent path is not synced, FaultInjectionTestFS::DeleteFilesCreatedAfterLastDirSync() will delete the file. However, RocksDB relies on file renaming to be atomic no matter whether the parent directory is synced or not, and the current behavior breaks the assumption and caused some false positive: https://github.com/facebook/rocksdb/pull/8489

Since the atomic renaming is used in CURRENT files, to fix the problem, in FaultInjectionTestFS::DeleteFilesCreatedAfterLastDirSync(), we recover the state of overwritten file if the file is small.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8501

Test Plan: Run stress test for a while and see it doesn't break.

Reviewed By: anand1976

Differential Revision: D29594384

fbshipit-source-id: 589b5c2f0a9d2aca53752d7bdb0231efa5b3ae92
2021-07-07 16:23:23 -07:00
anand76
fcd8088333 Temporarily disable file deletion after open failure in db_stress (#8489)
Summary:
Write and metadata error injection during DB open was enabled in https://github.com/facebook/rocksdb/issues/8474. This causes crash tests to fail very frequently due to another fault injection feature that deletes files created after the last dir sync during DB open. In real life, a similar failure would happen if the FS returns error on the CURRENT file rename, but the rename actually succeeded and got partially persisted (dir entry for the old CURRENT file got removed, but the entry for the new one is not persisted). Temporarily disable the fault injection feature until we figure out the likelihood of this bug happening and the proper way to fix it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8489

Test Plan: Stress test can open the DB successfully

Reviewed By: siying

Differential Revision: D29564516

Pulled By: anand1976

fbshipit-source-id: ffd1650715ea3c5bf7131936b0ca6fcf66f4e14e
2021-07-06 14:16:57 -07:00
sdong
f33611d5e9 Stress test to inject read failures in DB reopen (#8476)
Summary:
Inject read failures in DB reopen, just as what we do for metadata writes and writes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8476

Test Plan: Some manual tests and make sure failures are triggered.

Reviewed By: anand1976

Differential Revision: D29507283

fbshipit-source-id: d04da0163973447041038bd87701686a417c4e0c
2021-07-06 11:05:27 -07:00
mrambacher
570248aeff Make SecondaryCache Customizable (#8480)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8480

Reviewed By: zhichao-cao

Differential Revision: D29528740

Pulled By: mrambacher

fbshipit-source-id: fd0f70d15f66611c8498257a9973f7e98ca13839
2021-07-06 09:18:08 -07:00
Zhichao Cao
a95a776d75 Inject fatal write failures to db_stress when DB is running (#8479)
Summary:
add the injest_error_severity to control if it is a retryable IO Error or a fatal or unrecoverable error. Use a flag to indicate, if fatal error comes, the flag is set and db is stopped (but not corrupted).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8479

Test Plan: run  ./db_stress --reopen=0 --read_fault_one_in=1000 --write_fault_one_in=5 --disable_wal=true --write_buffer_size=3000000 -writepercent=5 -readpercent=50 --injest_error_severity=2 --column_families=1, make check

Reviewed By: anand1976

Differential Revision: D29524271

Pulled By: zhichao-cao

fbshipit-source-id: 1aa9fb9b5655b0adba6f5ad12005ca8c074c795b
2021-07-01 14:16:47 -07:00
sdong
ba224b75c7 Stress Test to inject write failures in reopen (#8474)
Summary:
Previously Stress can inject metadata write failures when reopening a DB. We extend it to file append too, in the same way.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8474

Test Plan: manually run crash test with various setting and make sure the failures are triggered as expected.

Reviewed By: zhichao-cao

Differential Revision: D29503116

fbshipit-source-id: e73a446e80ccbd09301a579280e56ff949381fab
2021-06-30 16:46:41 -07:00
anand76
6f9ed59b1d Allow db_stress to use a secondary cache (#8455)
Summary:
Add a ```-secondary_cache_uri``` to db_stress to allow the user to specify a custom ```SecondaryCache``` object from the object registry. Also allow db_crashtest.py to be run with an alternate db_stress location. Together, these changes will allow us to run db_stress using FB internal components.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8455

Reviewed By: zhichao-cao

Differential Revision: D29371972

Pulled By: anand1976

fbshipit-source-id: dd1b1fd80ebbedc11aa63d9246ea6ae49edb77c4
2021-06-27 23:54:39 -07:00
Akanksha Mahajan
be8199cdb9 Run Merge with Integrated BlobDB in stress, crash and db_bench (#8461)
Summary:
Run Merge with Intergrated BlobDB in stress tests, crash tests and db_bench.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8461

Test Plan:
1. python3 -u tools/db_crashtest.py --simple whitebox
---use_merge=1 --enable_blob_files=1
           2.  ./db_bench --benchmarks="readwhilemerging"
--merge_operator=uint64add --enable_blob_files=true

Reviewed By: ltamasi

Differential Revision: D29394824

Pulled By: akankshamahajan15

fbshipit-source-id: 0a8e492b13129673e088fb8af3402ab678bb473a
2021-06-25 10:45:52 -07:00
Peter Dillinger
865a25101d Mark Ribbon filter and optimize_filters_for_memory as production (#8408)
Summary:
Marked the Ribbon filter and optimize_filters_for_memory features
as production-ready, each enabling memory savings for Bloom-like filters.
Use `NewRibbonFilterPolicy` in place of `NewBloomFilterPolicy` to use
Ribbon filters instead of Bloom, or `ribbonfilter` in place of
`bloomfilter` in configuration string.

Some small refactoring in db_stress.

Removed/refactored unused code in db_bench, in part preparing for future
default possibly being different from "disabled."

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8408

Test Plan:
Lots of prior automated, ad-hoc, and "real world" testing.
Updated tests for new API names. Quick db_bench test:

bloom fillrandom
77730 ops/sec
rocksdb.block.cache.filter.bytes.insert COUNT : 89929384

ribbon fillrandom
71492 ops/sec
rocksdb.block.cache.filter.bytes.insert COUNT : 64531384

Reviewed By: mrambacher

Differential Revision: D29140805

Pulled By: pdillinger

fbshipit-source-id: d742c922722421678f95ad85eeb0aaebc9f5e49a
2021-06-17 12:29:16 -07:00
sdong
7f3a0f5bc6 db_stress: wait for compaction to finish after open with failure injection (#8270)
Summary:
When injecting in DB open, error can happen in background threads, causing DB open succeed, but DB is soon made read-only and subsequence writes will fail, which is not expected. To prevent it from happening, wait for compaction to finish before serving the traffic. If there is a failure, reopen.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8270

Test Plan: Run the test.

Reviewed By: ajkr

Differential Revision: D28230537

fbshipit-source-id: e2e97888904f9b9bb50c35ccf95b88c2319ef5c3
2021-05-05 16:41:45 -07:00
sdong
e19908cba6 Refactor kill point (#8241)
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
2021-05-05 15:50:29 -07:00
Andrew Kryczka
0f42e50fec Fix GetLiveFiles() returning OPTIONS-000000 (#8268)
Summary:
See release note in HISTORY.md.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8268

Test Plan: unit test repro

Reviewed By: siying

Differential Revision: D28227901

Pulled By: ajkr

fbshipit-source-id: faf61d13b9e43a761e3d5dcf8203923126b51339
2021-05-05 12:54:46 -07:00
sdong
cde69a7cfd db_stress to add --open_metadata_write_fault_one_in (#8235)
Summary:
DB Stress to add --open_metadata_write_fault_one_in which would randomly fail in some file metadata modification operations during DB Open, including file creation, close, renaming and directory sync. Some operations can fail before and after the operations take place.
If DB open fails, db_stress would retry without the failure ingestion, and DB is expected to open successfully.
This option is enabled in crash test in half of the time.
Some follow up changes would allow write failures in open time, and ingesting those failures in non-DB open cases.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8235

Test Plan: Run stress tests for a while and see failures got triggered. This can reproduce the bug fixed by https://github.com/facebook/rocksdb/pull/8192 and a similar one that fails when fsyncing parent directory.

Reviewed By: anand1976

Differential Revision: D28010944

fbshipit-source-id: 36a96da4dc3633e5f7680cef3ea0a900fcdb5558
2021-04-28 10:58:05 -07:00
Peter Dillinger
95f6add746 Revert Ribbon starting level support from #8198 (#8212)
Summary:
This partially reverts commit 10196d7edc.

The problem with this change is because of important filter use cases:
FIFO compaction and SST writer. FIFO "compaction" always uses level 0 so
would only use Ribbon filters if specifically including level 0 for the
Ribbon filter policy. SST writer sets level_at_creation=-1 to indicate
unknown level, and this would be treated the same as level 0 unless
fixed.

We are keeping the part about committing to permanent schema, which is
only changes to API comments and HISTORY.md.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8212

Test Plan: CI

Reviewed By: jay-zhuang

Differential Revision: D27896468

Pulled By: pdillinger

fbshipit-source-id: 50a775f7cba5d64fb729d9b982e355864020596e
2021-04-20 19:46:40 -07:00
Peter Dillinger
10196d7edc Ribbon long-term support, starting level support (#8198)
Summary:
Since the Ribbon filter schema seems good (compatible back to
6.15.0), this change commits to long term support of the SST schema,
even though we expect the API for enabling Ribbon to change (still
called NewExperimentalRibbonFilterPolicy).

This also adds support for "hybrid" configuration in which some levels
use Bloom (higher levels, lower numbered) for speed and the rest use
Ribbon (lower levels, higher numbered) for memory space efficiency.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8198

Test Plan: unit test added, crash test support

Reviewed By: jay-zhuang

Differential Revision: D27831232

Pulled By: pdillinger

fbshipit-source-id: 90e528677689474d293ed6710b42ba89fbd5b5ab
2021-04-16 15:43:08 -07:00
Akanksha Mahajan
0be89e87fd Enable backup/restore for Integrated BlobDB in stress and crash tests (#8165)
Summary:
Enable backup/restore functionality with Integrated BlobDB in
db_stress and crash test.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8165

Test Plan:
Ran python3 -u tools/db_crashtest.py --simple whitebox along
with :
  1. decreased "backup_in_one" value for backups to be more frequent and
  2. manually changed code for "enable_blob_file" to be always true and
     apply blobdb params 100% for testing purpose.

Reviewed By: ltamasi

Differential Revision: D27636025

Pulled By: akankshamahajan15

fbshipit-source-id: 0d0e0d1479ced163f992872dc998e79c581bfc99
2021-04-07 17:57:24 -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
Yanqin Jin
08144bc2f5 Add user-defined timestamps to db_stress (#8061)
Summary:
Add some basic test for user-defined timestamp to db_stress. Currently,
read with timestamp always tries to read using the current timestamp.
Due to the per-key timestamp-sequence ordering constraint, we only add timestamp-
related tests to the `NonBatchedOpsStressTest` since this test serializes accesses
to the same key and uses a file to cross-check data correctness.
The timestamp feature is not supported in a number of components, e.g. Merge, SingleDelete,
DeleteRange, CompactionFilter, Readonly instance, secondary instance, SST file ingestion, transaction,
etc. Therefore, db_stress should exit if user enables both timestamp and these features at the same
time. The (currently) incompatible features can be found in
`CheckAndSetOptionsForUserTimestamp`.

This PR also fixes a bug triggered when timestamp is enabled together with
`index_type=kBinarySearchWithFirstKey`. This bug fix will also be in another separate PR
with more unit tests coverage. Fixing it here because I do not want to exclude the index type
from crash test.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8061

Test Plan: make crash_test_with_ts

Reviewed By: jay-zhuang

Differential Revision: D27056282

Pulled By: riversand963

fbshipit-source-id: c3e00ad1023fdb9ebbdf9601ec18270c5e2925a9
2021-03-23 05:13:30 -07:00
Levi Tamasi
0d800dadea Adjust the set of potential min_blob_size values in stress/crash tests (#8085)
Summary:
Since our stress/crash tests by default generate values of size 8, 16, or 24,
it does not make much sense to set `min_blob_size` to 256. The patch
updates the set of potential `min_blob_size` values in the crash test
script and in `db_stress` where it might be set dynamically using
`SetOptions`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8085

Test Plan: Ran `make check` and tried the crash test script.

Reviewed By: riversand963

Differential Revision: D27238620

Pulled By: ltamasi

fbshipit-source-id: 4a96f9944b1ed9220d3045c5ab0b34c49009aeee
2021-03-22 14:38:09 -07:00
Peter Dillinger
3bfd3ed2f3 Begin forward compatibility for new backup meta schema (#8069)
Summary:
This does not add any new public APIs or published
functionality, but adds the ability to read and use (and in tests,
write) backups with a new meta file schema, based on the old schema
but not forward-compatible (before this change). The new schema enables
some capabilities not in the old:

* Explicit versioning, so that users get clean error messages the next
time we want to break forward compatibility.
* Ignoring unrecognized fields (with warning), so that new non-critical
features can be added without breaking forward compatibility.
* Rejecting future "non-ignorable" fields, so that new features critical
to some use-cases could potentially be added outside of linear schema
versions, with broken forward compatibility.
* Fields at the end of the meta file, such as for checksum of the meta
file's contents (up to that point)
* New optional 'size' field for each file, which is checked when present
* Optionally omitting 'crc32' field, so that we aren't required to have
a crc32c checksum for files to take a backup. (E.g. to support backup
via hard links and to better support file custom checksums.)

Because we do not have a JSON parser and to share code, the new schema
is simply derived from the old schema.

BackupEngine code is updated to allow missing checksums in some places,
and to make that easier, `has_checksum` and `verify_checksum_after_work`
are eliminated. Empty `checksum_hex` indicates checksum is unknown. I'm
not too afraid of regressing on data integrity, because
(a) we have pretty good test coverage of corruption detection in backups, and
(b) we are increasingly relying on the DB itself for data integrity rather than
it being an exclusive feature of backups.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8069

Test Plan:
new unit tests, added to crash test (some local run with
boosted backup probability)

Reviewed By: ajkr

Differential Revision: D27139824

Pulled By: pdillinger

fbshipit-source-id: 9e0e4decfb42bb84783d64d2d246456d97e8e8c5
2021-03-19 20:15:40 -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
Peter Dillinger
847ca9f964 Make default share_files_with_checksum=true (#8020)
Summary:
New comment for share_files_with_checksum:
// Only used if share_table_files is set to true. Setting to false is
// DEPRECATED and potentially dangerous because in that case BackupEngine
// can lose data if backing up databases with distinct or divergent
// history, for example if restoring from a backup other than the latest,
// writing to the DB, and creating another backup. Setting to true (default)
// prevents these issues by ensuring that different table files (SSTs) with
// the same number are treated as distinct. See
// share_files_with_checksum_naming and ShareFilesNaming.

I have also removed interim option kFlagMatchInterimNaming, which is no
longer needed and was never needed for correct+compatible operation
(just performance).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8020

Test Plan:
tests updated. Backward+forward compatibility verified with
SHORT_TEST=1 check_format_compatible.sh. ldb uses default backup
options, and I manually verified shared_checksum in
/tmp/rocksdb_format_compatible_peterd/bak/current/ after run.

Reviewed By: ajkr

Differential Revision: D26786331

Pulled By: pdillinger

fbshipit-source-id: 36f968dfef1f5cacbd65154abe1d846151a55130
2021-03-09 16:27:13 -08:00
Yanqin Jin
1f11d07f24 Enable compact filter for blob in dbstress and dbbench (#8011)
Summary:
As title.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8011

Test Plan:
```
./db_bench -enable_blob_files=1 -use_keep_filter=1 -disable_auto_compactions=1
/db_stress -enable_blob_files=1 -enable_compaction_filter=1 -acquire_snapshot_one_in=0 -compact_range_one_in=0 -iterpercent=0 -test_batches_snapshots=0 -readpercent=10 -prefixpercent=20 -writepercent=55 -delpercent=15 -continuous_verification_interval=0
```

Reviewed By: ltamasi

Differential Revision: D26736061

Pulled By: riversand963

fbshipit-source-id: 1c7834903c28431ce23324c4f259ed71255614e2
2021-03-01 17:24:47 -08:00
Andrew Kryczka
d904233d2f Limit buffering for collecting samples for compression dictionary (#7970)
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
2021-02-19 14:09:54 -08:00
Levi Tamasi
dab4fe5bcd Add checkpoint support to BlobDB (#7959)
Summary:
The patch adds checkpoint support to BlobDB. Blob files are hard linked or
copied, depending on whether the checkpoint directory is on the same filesystem
or not, similarly to table files.

TODO: Add support for blob files to `ExportColumnFamily` and to the checksum
verification logic used by backup/restore.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7959

Test Plan: Ran `make check` and the crash test for a while.

Reviewed By: riversand963

Differential Revision: D26434768

Pulled By: ltamasi

fbshipit-source-id: 994be55a8dc08133028250760fca440d2c7c4dc5
2021-02-17 12:42:36 -08:00
Levi Tamasi
0288bdbc53 Add the integrated BlobDB to the stress/crash tests (#7900)
Summary:
The patch adds support for the options related to the new BlobDB implementation
to `db_stress`, including support for dynamically adjusting them using `SetOptions`
when `set_options_one_in` and a new flag `allow_setting_blob_options_dynamically`
are specified. (The latter is used to prevent the options from being enabled when
incompatible features are in use.)

The patch also updates the `db_stress` help messages of the existing stacked BlobDB
related options to clarify that they pertain to the old implementation. In addition, it
adds the new BlobDB to the crash test script. In order to prevent a combinatorial explosion
of jobs and still perform whitebox/blackbox testing (including under ASAN/TSAN/UBSAN),
and to also test BlobDB in conjunction with atomic flush and transactions, the script sets
the BlobDB options in 10% of normal/`cf_consistency`/`txn` crash test runs.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7900

Test Plan: Ran `make check` and `db_stress`/`db_crashtest.py` with various options.

Reviewed By: jay-zhuang

Differential Revision: D26094913

Pulled By: ltamasi

fbshipit-source-id: c2ef3391a05e43a9687f24e297df05f4a5584814
2021-02-02 11:41:18 -08:00
Cheng Chang
30cd38c687 Increase the txn lock timeout in stress test (#7823)
Summary:
We recently encounter two cases of txn lock timeout in stress test. It might be caused due to latencies of resource scheduling in the internal infrastructure. Hopefully increasing the timeout can make the related tests less flaky.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7823

Test Plan: watch internal stress test to pass.

Reviewed By: siying

Differential Revision: D25739233

Pulled By: cheng-chang

fbshipit-source-id: 84a5a8ae820db24dacd0cfc05928b26505fab89d
2020-12-30 20:31:35 -08:00
Zhichao Cao
601585bca4 fix memory leak in db_stress checkpoint test (#7813)
Summary:
fix memory leak in db_stress checkpoint test. If s is not ok, checkpoint is not deleted, may cause memory leak.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7813

Test Plan: make asan_check

Reviewed By: cheng-chang

Differential Revision: D25702999

Pulled By: zhichao-cao

fbshipit-source-id: 08253b0852835acb8cfd412503cdabf720afb678
2020-12-25 13:15:48 -08:00
Zhichao Cao
04b3524ad0 Inject the random write error to stress test (#7653)
Summary:
Inject the random write error to stress test, it requires set reopen=0 and disable_wal=true.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7653

Test Plan: pass db_stress and python3 db_crashtest.py blackbox

Reviewed By: ajkr

Differential Revision: D25354132

Pulled By: zhichao-cao

fbshipit-source-id: 44721104eecb416e27f65f854912c40e301dd669
2020-12-17 11:52:28 -08:00
Peter Dillinger
60af964372 Experimental (production candidate) SST schema for Ribbon filter (#7658)
Summary:
Added experimental public API for Ribbon filter:
NewExperimentalRibbonFilterPolicy(). This experimental API will
take a "Bloom equivalent" bits per key, and configure the Ribbon
filter for the same FP rate as Bloom would have but ~30% space
savings. (Note: optimize_filters_for_memory is not yet implemented
for Ribbon filter. That can be added with no effect on schema.)

Internally, the Ribbon filter is configured using a "one_in_fp_rate"
value, which is 1 over desired FP rate. For example, use 100 for 1%
FP rate. I'm expecting this will be used in the future for configuring
Bloom-like filters, as I expect people to more commonly hold constant
the filter accuracy and change the space vs. time trade-off, rather than
hold constant the space (per key) and change the accuracy vs. time
trade-off, though we might make that available.

### Benchmarking

```
$ ./filter_bench -impl=2 -quick -m_keys_total_max=200 -average_keys_per_filter=100000 -net_includes_hashing
Building...
Build avg ns/key: 34.1341
Number of filters: 1993
Total size (MB): 238.488
Reported total allocated memory (MB): 262.875
Reported internal fragmentation: 10.2255%
Bits/key stored: 10.0029
----------------------------
Mixed inside/outside queries...
  Single filter net ns/op: 18.7508
  Random filter net ns/op: 258.246
    Average FP rate %: 0.968672
----------------------------
Done. (For more info, run with -legend or -help.)
$ ./filter_bench -impl=3 -quick -m_keys_total_max=200 -average_keys_per_filter=100000 -net_includes_hashing
Building...
Build avg ns/key: 130.851
Number of filters: 1993
Total size (MB): 168.166
Reported total allocated memory (MB): 183.211
Reported internal fragmentation: 8.94626%
Bits/key stored: 7.05341
----------------------------
Mixed inside/outside queries...
  Single filter net ns/op: 58.4523
  Random filter net ns/op: 363.717
    Average FP rate %: 0.952978
----------------------------
Done. (For more info, run with -legend or -help.)
```

168.166 / 238.488 = 0.705  -> 29.5% space reduction

130.851 / 34.1341 = 3.83x construction time for this Ribbon filter vs. lastest Bloom filter (could make that as little as about 2.5x for less space reduction)

### Working around a hashing "flaw"

bloom_test discovered a flaw in the simple hashing applied in
StandardHasher when num_starts == 1 (num_slots == 128), showing an
excessively high FP rate.  The problem is that when many entries, on the
order of number of hash bits or kCoeffBits, are associated with the same
start location, the correlation between the CoeffRow and ResultRow (for
efficiency) can lead to a solution that is "universal," or nearly so, for
entries mapping to that start location. (Normally, variance in start
location breaks the effective association between CoeffRow and
ResultRow; the same value for CoeffRow is effectively different if start
locations are different.) Without kUseSmash and with num_starts > 1 (thus
num_starts ~= num_slots), this flaw should be completely irrelevant.  Even
with 10M slots, the chances of a single slot having just 16 (or more)
entries map to it--not enough to cause an FP problem, which would be local
to that slot if it happened--is 1 in millions. This spreadsheet formula
shows that: =1/(10000000*(1 - POISSON(15, 1, TRUE)))

As kUseSmash==false (the setting for Standard128RibbonBitsBuilder) is
intended for CPU efficiency of filters with many more entries/slots than
kCoeffBits, a very reasonable work-around is to disallow num_starts==1
when !kUseSmash, by making the minimum non-zero number of slots
2*kCoeffBits. This is the work-around I've applied. This also means that
the new Ribbon filter schema (Standard128RibbonBitsBuilder) is not
space-efficient for less than a few hundred entries. Because of this, I
have made it fall back on constructing a Bloom filter, under existing
schema, when that is more space efficient for small filters. (We can
change this in the future if we want.)

TODO: better unit tests for this case in ribbon_test, and probably
update StandardHasher for kUseSmash case so that it can scale nicely to
small filters.

### Other related changes

* Add Ribbon filter to stress/crash test
* Add Ribbon filter to filter_bench as -impl=3
* Add option string support, as in "filter_policy=experimental_ribbon:5.678;"
where 5.678 is the Bloom equivalent bits per key.
* Rename internal mode BloomFilterPolicy::kAuto to kAutoBloom
* Add a general BuiltinFilterBitsBuilder::CalculateNumEntry based on
binary searching CalculateSpace (inefficient), so that subclasses
(especially experimental ones) don't have to provide an efficient
implementation inverting CalculateSpace.
* Minor refactor FastLocalBloomBitsBuilder for new base class
XXH3pFilterBitsBuilder shared with new Standard128RibbonBitsBuilder,
which allows the latter to fall back on Bloom construction in some
extreme cases.
* Mostly updated bloom_test for Ribbon filter, though a test like
FullBloomTest::Schema is a next TODO to ensure schema stability
(in case this becomes production-ready schema as it is).
* Add some APIs to ribbon_impl.h for configuring Ribbon filters.
Although these are reasonably covered by bloom_test, TODO more unit
tests in ribbon_test
* Added a "tool" FindOccupancyForSuccessRate to ribbon_test to get data
for constructing the linear approximations in GetNumSlotsFor95PctSuccess.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7658

Test Plan:
Some unit tests updated but other testing is left TODO. This
is considered experimental but laying down schema compatibility as early
as possible in case it proves production-quality. Also tested in
stress/crash test.

Reviewed By: jay-zhuang

Differential Revision: D24899349

Pulled By: pdillinger

fbshipit-source-id: 9715f3e6371c959d923aea8077c9423c7a9f82b8
2020-11-12 20:46:14 -08:00
Cheng Chang
c3911f1a72 Track WAL in MANIFEST: Track deleted WALs in MANIFEST after recovering from the WALs (#7649)
Summary:
After replaying the WALs, the memtables are flushed synchronously to L0 instead of being flushed in background. Currently, we only track WAL obsoletion events in the code path of background flush jobs. This PR tracks these events in RecoverLogFiles.

After this change, we can enable `track_and_verify_wal_in_manifest` in `db_stress`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7649

Test Plan: `python tools/db_crashtest.py whitebox`

Reviewed By: riversand963

Differential Revision: D24824501

Pulled By: cheng-chang

fbshipit-source-id: 207129f7b845c50b333680ce6818a68a2fad54b9
2020-11-09 10:25:43 -08:00
Cheng Chang
5e794b0841 Fix a recovery corner case (#7621)
Summary:
Consider the following sequence of events:

1. Db flushed an SST with file number N, appended to MANIFEST, and tried to sync the MANIFEST.
2. Syncing MANIFEST failed and db crashed.
3. Db tried to recover with this MANIFEST. In the meantime, no entry about the newly-flushed SST was found in the MANIFEST. Therefore, RocksDB replayed WAL and tried to flush to an SST file reusing the same file number N. This failed because file system does not support overwrite. Then Db deleted this file.
4. Db crashed again.
5. Db tried to recover. When db read the MANIFEST, there was an entry referencing N.sst. This could happen probably because the append in step 1 finally reached the MANIFEST and became visible. Since N.sst had been deleted in step 3, recovery failed.

It is possible that N.sst created in step 1 is valid. Although step 3 would still fail since the MANIFEST was not synced properly in step 1 and 2, deleting N.sst would make it impossible for the db to recover even if the remaining part of MANIFEST was appended and visible after step 5.

After this PR, in step 3, immediately after recovering from MANIFEST, a new MANIFEST is created, then we find that N.sst is not referenced in the MANIFEST, so we delete it, and we'll not reuse N as file number. Then in step 5, since the new MANIFEST does not contain N.sst, the recovery failure situation in step 5 won't happen.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7621

Test Plan:
1. some tests are updated, because these tests assume that new MANIFEST is created after WAL recovery.
2. a new unit test is added in db_basic_test to simulate step 3.

Reviewed By: riversand963

Differential Revision: D24668144

Pulled By: cheng-chang

fbshipit-source-id: 90d7487fbad2bc3714f5ede46ea949895b15ae3b
2020-11-07 22:23:27 -08:00
Cheng Chang
1e40696dd1 Track WAL in MANIFEST: LogAndApply WAL events to MANIFEST (#7601)
Summary:
When a WAL is synced, an edit is written to MANIFEST.
After flushing memtables, the obsoleted WALs are piggybacked to MANIFEST while writing the new L0 files to MANIFEST.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7601

Test Plan:
`track_and_verify_wals_in_manifest` is enabled by default for all tests extending `DBBasicTest`, and in db_stress_test.
Unit test `wal_edit_test`, `version_edit_test`, and `version_set_test` are also updated.
Watch all tests to pass.

Reviewed By: ltamasi

Differential Revision: D24553957

Pulled By: cheng-chang

fbshipit-source-id: 66a569ff1bdced38e22900bd240b73113906e040
2020-11-06 17:22:36 -08:00