Summary:
Refactor dump_tool and undump_tool so that it's possible to use them with customized options
for example setting a specific comparator similar to what Dragon is doing with the LdbTool

https://phabricator.fb.com/diffusion/FBCODE/browse/master/dragon/tools/Ldb.cpp

Test Plan:
compiles
used it to dump / undump a dragon shard

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba, adsharma

Differential Revision: https://reviews.facebook.net/D47853

Summary:
Fixed the following tsan warning in db_stress.cc

  WARNING: ThreadSanitizer: data race (pid=3163194)
  Read of size 8 at 0x7fd1797cb518 by thread T32:
    #0 VerifyDb tools/db_stress.cc:1731 (db_stress+0x000000040674)
    #1 rocksdb::StressTest::ThreadBody(void*) tools/db_stress.cc:1191 (db_stress+0x0000000625a9)
    #2 StartThreadWrapper util/env_posix.cc:1648 (db_stress+0x00000028bbbd)

  Previous write of size 8 at 0x7fd1797cb518 by thread T31:
    #0 VerifyDb tools/db_stress.cc:1726 (db_stress+0x00000004072a)
    #1 rocksdb::StressTest::ThreadBody(void*) tools/db_stress.cc:1191 (db_stress+0x0000000625a9)
    #2 StartThreadWrapper util/env_posix.cc:1648 (db_stress+0x00000028bbbd)

The cause is that in VerifyDb(), the static local const variable long max_key
can be read and written at the same time.  This patch fixed it by making it
non-static.

Test Plan: db_stress

Reviewers: igor, sdong, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47703

Summary:
This patch fixes #7460559. It introduces SingleDelete as a new database
operation. This operation can be used to delete keys that were never
overwritten (no put following another put of the same key). If an overwritten
key is single deleted the behavior is undefined. Single deletion of a
non-existent key has no effect but multiple consecutive single deletions are
not allowed (see limitations).

In contrast to the conventional Delete() operation, the deletion entry is
removed along with the value when the two are lined up in a compaction. Note:
The semantics are similar to @igor's prototype that allowed to have this
behavior on the granularity of a column family (
https://reviews.facebook.net/D42093 ). This new patch, however, is more
aggressive when it comes to removing tombstones: It removes the SingleDelete
together with the value whenever there is no snapshot between them while the
older patch only did this when the sequence number of the deletion was older
than the earliest snapshot.

Most of the complex additions are in the Compaction Iterator, all other changes
should be relatively straightforward. The patch also includes basic support for
single deletions in db_stress and db_bench.

Limitations:
- Not compatible with cuckoo hash tables
- Single deletions cannot be used in combination with merges and normal
  deletions on the same key (other keys are not affected by this)
- Consecutive single deletions are currently not allowed (and older version of
  this patch supported this so it could be resurrected if needed)

Test Plan: make all check

Reviewers: yhchiang, sdong, rven, anthony, yoshinorim, igor

Reviewed By: igor

Subscribers: maykov, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43179

Summary:
Added tests for two LDBCommands namely i) ManifestDumpCommand and ii) ListColumnFamiliesCommand.
+ Minor fix in the sscanf formatter (along relace C cast with C++ cast) + replacing localtime with localtime_r which is thread safe.

Test Plan: make all && ./tools/ldb_test.py

Reviewers: anthony, igor, IslamAbdelRahman, kradhakrishnan, lgalanis, rven, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45819

Summary: Add ZSTD compression type. The same way as adding LZ4.

Test Plan: run all tests. Generate files in db_bench. Make sure reads succeed. But the SST files cannot be opened in older versions. Also some other adhoc tests.

Reviewers: rven, anthony, IslamAbdelRahman, kradhakrishnan, igor

Reviewed By: igor

Subscribers: MarkCallaghan, maykov, yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45747

Summary:
db_bench output now displays Percentile many times with --statistics after
read IO latency histograms were added. So I only need the last one in the report output.

Task ID: #

Blame Rev:

Test Plan:
run run_flash_bench.sh

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45093

Summary:
Up until this point we had DbOptions.num_subcompactions, but
it is semantically more correct to call this max_subcompactions since
we will schedule *up to* DbOptions.max_subcompactions smaller compactions
at a time during a compaction job.

I also added a --subcompactions option to db_bench

Test Plan: make all   make check

Reviewers: sdong, igor, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45069

Summary:
Changes include:
* don't sync-on-commit for single writer thread in readwhile... tests
* make default block size 8kb rather than 4kb to avoid too small blocks after compression
* use snappy instead of zlib to avoid stalls from compression latency
* disable statistics
* use bytes_per_sync=8M to reduce throughput loss on disk
* use open_files=-1 to reduce mutex contention

Task ID: #

Blame Rev:

Test Plan:
run benchmark

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D44961

Summary:
In prepration for running multiple threads at the same time during
a compaction job, this patch assigns each subcompaction its own state
(instead of sharing the one global CompactionState). Each subcompaction then
uses this state to update its statistics, keep track of its snapshots, etc.
during the course of execution. Then at the end of all the executions the
statistics are aggregated across the subcompactions so that the final result
is the same as if only one larger compaction had run.

Test Plan: ./db_test  ./db_compaction_test  ./compaction_job_test

Reviewers: sdong, anthony, igor, noetzli, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43239

Summary:
While working on single delete support for db_bench, I realized that
db_bench/db_stress contain a bunch of duplicate code related to
copmression and found some typos. This patch removes duplicate code,
typos and a redundant #ifndef in internal_stats.cc.

Test Plan: make db_stress && make db_bench && ./db_bench --benchmarks=compress,uncompress

Reviewers: yhchiang, sdong, rven, anthony, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43965

Summary: In a recent change, crash_test can put data under TEST_TMPDIR. However, the directory is not cleaned before running the test, which may cause unexpected results. Clean it.

Test Plan: Run white and black box crash test against non-existing, or non-empty but not compactible DBs, and make sure it works as expected.

Reviewers: kradhakrishnan, rven, yhchiang, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43515

Summary: Currently, whitebox crash test is not really executed, because the DB is destroyed after each crash. With this fix, in the first half of the time, DB will keep opening the crashed DB and continue from there.

Test Plan: "make whitebox_crash_test" and see the same DB keeps crashing and being reopened.

Reviewers: IslamAbdelRahman, yhchiang, rven, kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43503

Summary: Currently crash_test only puts data under /tmp. It is less flexible if we want to cover different file systems or media. Make crash_test to appreciate TEST_TMPDIR so that users can run it against another file system.

Test Plan: Run blackbox_crash_test and whitebox_crash_test with or without TEST_TMPDIR set and make sure DBs are put in the right place

Reviewers: kradhakrishnan, yhchiang, rven, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43509

Summary:
crash_test now only runs complicated options, multiple column families, prefix hash, frequently changing options, many compaction threads, etc. These options are good to cover new features but we loss coverage in most common use cases. Furthermore, by running only for multiple column families, we are not able to create LSM trees that are large enough to cover some stress cases.
Make half of crash_test runs the simply tests: single column family, default mem table, one compaction thread, no change options.

Test Plan: Run crash_test

Reviewers: rven, yhchiang, IslamAbdelRahman, kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43461

Summary: Fixed typos.

Test Plan: None

Reviewers: igor, yhchiang, sdong, anthony, rven

Reviewed By: rven

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43365

Summary:
Crash tests are supposed to restart the same DB after crashing, but it is now opening a different DB. Fix it.
It's probably a leftover of https://reviews.facebook.net/D17073

Test Plan: Run the test and make sure the same Db is opened.

Reviewers: kradhakrishnan, rven, igor, IslamAbdelRahman, yhchiang, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43197

 Add heap_test, merge_helper_test
 Fix uninitialized pointers in db_sanity_test that cause SIGSEV when DB::Open fails in case compression is not linked.

Summary:
When we first started, max_background_flushes was 0 by default and compaction thread was executing flushes (since there was no flush thread). Then, we switched the default max_background_flushes to 1. However, we still support the case where there is no flush thread and flushes are done in compaction. This is making our code a bit more complicated. By not supporting this use-case we can make our code simpler.

We have a special case that when you set max_background_flushes to 0, we
schedule the flush to execute on the compaction thread.

Test Plan: make check (there might be some unit tests that depend on this behavior)

Reviewers: IslamAbdelRahman, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41931

Summary: This is failing our tsan tests. Our new behavior is to fail DB::Open() if the requested compression is not available. The easiest fix is to make ldb_test not depend on compression.

Test Plan: python tools/ldb_test.py

Reviewers: sdong, yhchiang, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42075

Summary: This option is guarding the feature implemented 2 and a half years ago: D8991. The feature was enabled by default back then and has been running without issues. There is no reason why any client would turn this feature off. I found no reference in fbcode.

Test Plan: none

Reviewers: sdong, yhchiang, anthony, dhruba

Reviewed By: dhruba

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42063

Summary: Block reduce_levels_test in ROCKSDB_LITE as LDBCommand is not supported

Test Plan:
make reduce_levels_test -j64
OPT=-DROCKSDB_LITE make reduce_levels_test -j64
make check -j64

Reviewers: sdong, igor, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D41967

Summary: This helps Windows port to format their changes, as discussed. Might have formatted some other codes too becasue last 10 commits include more.

Test Plan: Build it.

Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D41961

 Summary: Make RocksDb build and run on Windows to be functionally
 complete and performant. All existing test cases run with no
 regressions. Performance numbers are in the pull-request.

 Test plan: make all of the existing unit tests pass, obtain perf numbers.

 Co-authored-by: Praveen Rao praveensinghrao@outlook.com
 Co-authored-by: Sherlock Huang baihan.huang@gmail.com
 Co-authored-by: Alex Zinoviev alexander.zinoviev@me.com
 Co-authored-by: Dmitri Smirnov dmitrism@microsoft.com

Summary: as title

Test Plan: make check

Reviewers: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D40785

Summary: Hack up rocksdb_dump and rocksdb_undump utilities to get this task rolling/promote discussion.

Test Plan: Dump/undump databases recursively to see if nothing is lost.

Reviewers: sdong, yhchiang, rven, anthony, kradhakrishnan, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D37269

Summary:
EventListener::OnFlushCompleted() now passes a structure instead
of a list of parameters.  This minimizes the API change in the
future.

Test Plan:
listener_test
compact_files_test
example/compact_files_example

Reviewers: kradhakrishnan, sdong, IslamAbdelRahman, rven, igor

Reviewed By: rven, igor

Subscribers: IslamAbdelRahman, rven, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39543

Summary:
Add EventListener::OnTableFileCreated(), which will be called
when a table file is created.  This patch is part of the
EventLogger and EventListener integration.

Test Plan: Augment existing test in db/listener_test.cc

Reviewers: anthony, kradhakrishnan, rven, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D38865

Summary:
Fixed db_stress by correcting the verification of column family
names in the Listener of db_stress

Test Plan: db_stress

Reviewers: igor, sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39255

Summary: Fixed a compile warning in db_stress in NDEBUG mode.

Test Plan: make OPT=-DNDEBUG db_stress

Reviewers: sdong, anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39213

Summary: Optimistic transactions supporting begin/commit/rollback semantics.  Currently relies on checking the memtable to determine if there are any collisions at commit time.  Not yet implemented would be a way of enuring the memtable has some minimum amount of history so that we won't fail to commit when the memtable is empty.  You should probably start with transaction.h to get an overview of what is currently supported.

Test Plan: Added a new test, but still need to look into stress testing.

Reviewers: yhchiang, igor, rven, sdong

Reviewed By: sdong

Subscribers: adamretter, MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D33435

Summary:
Fixed the following compile warning in db_stress:
error: 'OnCompactionCompleted' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]

Test Plan: make db_stress

Reviewers: sdong, igor, anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39207

Summary: Include EventListener in stress test.

Test Plan: make blackbox_crash_test whitebox_crash_test

Reviewers: anthony, igor, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D39105

Summary:
For transactions, we are using the memtables to validate that there are no write conflicts.  But after flushing, we don't have any memtables, and transactions could fail to commit.  So we want to someone keep around some extra history to use for conflict checking.  In addition, we want to provide a way to increase the size of this history if too many transactions fail to commit.

After chatting with people, it seems like everyone prefers just using Memtables to store this history (instead of a separate history structure).  It seems like the best place for this is abstracted inside the memtable_list.  I decide to create a separate list in MemtableListVersion as using the same list complicated the flush/installalflushresults logic too much.

This diff adds a new parameter to control how much memtable history to keep around after flushing.  However, it sounds like people aren't too fond of adding new parameters.  So I am making the default size of flushed+not-flushed memtables be set to max_write_buffers.  This should not change the maximum amount of memory used, but make it more likely we're using closer the the limit.  (We are now postponing deleting flushed memtables until the max_write_buffer limit is reached).  So while we might use more memory on average, we are still obeying the limit set (and you could argue it's better to go ahead and use up memory now instead of waiting for a write stall to happen to test this limit).

However, if people are opposed to this default behavior, we can easily set it to 0 and require this parameter be set in order to use transactions.

Test Plan: Added a xfunc test to play around with setting different values of this parameter in all tests.  Added testing in memtablelist_test and planning on adding more testing here.

Reviewers: sdong, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D37443

Summary:
See https://gist.github.com/mdcallag/b867ee051d765760be0d for a sample

Task ID: #

Blame Rev:

Test Plan:
Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D37971

Summary:
This runs a benchmark for LevelDB similar to what we have
in tools/run_flash_bench.sh. It requires changes to db_bench that I published
in a LevelDB fork on github.  Some results are at:
http://smalldatum.blogspot.com/2015/04/comparing-leveldb-and-rocksdb-take-2.html

Sample output:
ops/sec	mb/sec	usec/op	avg	p50	Test
525	16.4	1904.5	1904.5	111.0	fillseq.v32768
75187	15.5	13.3	13.3	4.4	fillseq.v200
28328	5.8	35.3	35.3	4.7	overwrite.t1.s0
175438	0.0	5.7	5.7	4.4	readrandom.t1
28490	5.9	35.1	35.1	4.7	overwrite.t1.s0
121951	0.0	8.2	8.2	5.7	readwhilewriting.t1

Task ID: #

Blame Rev:

Test Plan:
Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D37749

Summary: Build broken by https://github.com/facebook/rocksdb/commit/6ede020dc419c1621254f26060076ee6d2c2d792

Test Plan: make all

Reviewers: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D37689