Commit Graph

891 Commits

Author SHA1 Message Date
Alex Loukissas
b0980ff748 Fix unused parameter warnings. 2015-10-26 16:32:14 -07:00
Siying Dong
138876a62c Merge pull request #746 from ceph/wip-recycle
Add Options.recycle_log_file_num for Recycling WAL Files
2015-10-26 15:01:28 -07:00
sdong
d691111146 include/posix/io_posix.h should have a once declartion
Summary: include/posix/io_posix.h doesn't not prevent multiple includes. Need to fix it. It is also breaking unity build.

Test Plan: Run unity build and see error go away.

Reviewers: rven, igor, IslamAbdelRahman, kradhakrishnan, anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D49281
2015-10-23 07:45:00 -07:00
Siying Dong
8c11c5dee8 Merge pull request #768 from OpenChannelSSD/to_fb_master2
Split posix storage backend into Env and library
2015-10-22 13:33:51 -07:00
Javier González
6e6dd5f6f9 Split posix storage backend into Env and library
Summary: This patch splits the posix storage backend into Env and
the actual *File implementations. The motivation is to allow other Envs
to use posix as a library. This enables a storage backend different from
posix to split its secondary storage between a normal file system
partition managed by posix, and it own media.

Test Plan: No new functionality is added to posix Env or the library,
thus the current tests should suffice.
2015-10-22 17:31:31 +02:00
Alexey Maykov
980a82ee2f Fix a bug in GetApproximateSizes
Summary: Need to pass through the memtable parameter.

Test Plan: built, tested through myrocks

Reviewers: igor, sdong, rven

Reviewed By: rven

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D49167
2015-10-21 18:34:39 -07:00
Islam AbdelRahman
e3b1d23d3e Bump version to 4.2
Summary: Bump the version to 4.2 ( the unreleased version ), so that when fbcode_unittests run it can differentiate between old and new APIs

Test Plan: make check

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D49041
2015-10-19 15:05:59 -07:00
agiardullo
cfaa33f9a5 Update transaction iterator documentation
Summary: Remove warning about an issue that was resolved.  Turns out the issue was a false-alarm.

Test Plan: n/a

Reviewers: igor, yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D49011
2015-10-19 13:08:18 -07:00
Alexey Maykov
f18acd8875 Fixed the clang compilation failure
Summary: As above.

Test Plan: USE_CLANG=1 make check -j

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48981
2015-10-19 10:38:50 -07:00
Sage Weil
543c12ab06 options: add recycle_log_file_num option
Signed-off-by: Sage Weil <sage@redhat.com>
2015-10-18 21:21:24 -04:00
Sage Weil
1bcafb62f4 env: add ReuseWritableFile
Add an environment method to reuse an existing file.  Provide a generic
implementation that does a simple rename + open (writeable), and also a
posix variant that is more careful about error handling (if we fail to
open, do not rename, etc.).

Signed-off-by: Sage Weil <sage@redhat.com>
2015-10-18 21:21:24 -04:00
Alexey Maykov
e1a09a7703 Implementation for GetPropertiesOfTablesInRange
Summary: In MyRocks, it is sometimes important to get propeties only for the subset of the database. This diff implements the API in RocksDB.

Test Plan: ran the GetPropertiesOfTablesInRange

Reviewers: rven, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48651
2015-10-17 13:34:43 -07:00
Yueh-Hsuan Chiang
ad471453e8 Allow GetProperty to report the number of currently running flushes / compactions.
Summary:
Add rocksdb.num-running-compactions and rocksdb.num-running-flushes
to GetIntProperty() that reports the number of currently running
compactions / flushes.

Test Plan: augmented existing tests in db_test

Reviewers: igor, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48693
2015-10-17 00:16:36 -07:00
Jay Edgar
8f143e03fb Add ClearSnapshot()
Summary:
MyRocks needs the ability to clear a snapshot for Read Committed support

Test Plan: transaction_test

Reviewers: anthony

Reviewed By: anthony

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48861
2015-10-16 11:53:30 -07:00
sdong
666fb5df43 Remove DefaultCompactionFilterFactory.
Summary: DefaultCompactionFilterFactory is not used anymore after recent changes. Remove it.

Test Plan: Just run existing tests.

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

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48699
2015-10-14 11:02:30 -07:00
Yueh-Hsuan Chiang
29a47cd2b8 Include the time unit in the comment of perf_context timers
Summary: Include the time unit in the comment of perf_context timers

Test Plan: make perf_context_test

Reviewers: igor, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48663
2015-10-13 17:24:13 -07:00
sdong
35ad531be3 Seperate InternalIterator from Iterator
Summary:
Separate a new class InternalIterator from class Iterator, when the look-up is done internally, which also means they operate on key with sequence ID and type.

This change will enable potential future optimizations but for now InternalIterator's functions are still the same as Iterator's.
At the same time, separate the cleanup function to a separate class and let both of InternalIterator and Iterator inherit from it.

Test Plan: Run all existing tests.

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

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48549
2015-10-13 15:32:13 -07:00
Yueh-Hsuan Chiang
0bb8ea56be [RocksDB Options File] Add TableOptions section and support BlockBasedTable
Summary:
Introduce TableOptions section and support BlockBasedTable in RocksDB
options file.  A TableOptions section has the following format:

  [TableOptions/<FactoryClassName> "<ColumnFamily Name>"]

which includes information about its TableFactory class and belonging
column family.  Below is an example TableOptions section of a
BlockBasedTableOptions that belongs to the default column family:

  [TableOptions/BlockBasedTable "default"]
    format_version=0
    whole_key_filtering=true
    block_size_deviation=10
    block_size=4096
    block_restart_interval=16
    filter_policy=nullptr
    no_block_cache=false
    checksum=kCRC32c
    cache_index_and_filter_blocks=false
    index_type=kBinarySearch
    hash_index_allow_collision=true
    flush_block_policy_factory=FlushBlockBySizePolicyFactory

Currently, Cache-type options (i.e., block_cache and block_cache_compressed)
are not supported.

Test Plan: options_test

Reviewers: igor, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48435
2015-10-11 12:17:42 -07:00
Alexey Maykov
3d07b815f6 Passing table properties to compaction callback
Summary: It would be nice to have and access to table properties in compaction callbacks. In MyRocks project, it will make possible to update optimizer statistics online.

Test Plan: ran the unit test. Ran myrocks with the new way of collecting stats.

Reviewers: igor, rven, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48267
2015-10-09 18:10:55 -07:00
agiardullo
def74f8763 Deferred snapshot creation in transactions
Summary: Support for Transaction::CreateSnapshotOnNextOperation().  This is to fix a write-conflict race-condition that Yoshinori was running into when testing MyRocks with LinkBench.

Test Plan: New tests

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

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48099
2015-10-09 15:46:16 -07:00
agiardullo
c5f3707d42 DisableIndexing() for Transactions
Summary:
MyRocks reported some perfomance issues when inserting many keys into a transaction due to the cost of inserting new keys into WriteBatchWithIndex.  Frequently, they don't even need the keys to be indexed as they don't need to read them back.  DisableIndexing() can be used to avoid the cost of indexing.

I also plan on eventually investigating if we can improve WriteBatchWithIndex performance.  But even if we improved the perf here, it is still beneficial to be able to disable the indexing all together for large transactions.

Test Plan: unit test

Reviewers: igor, rven, yoshinorim, spetrunia, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48471
2015-10-09 15:36:09 -07:00
sdong
776bd8d5eb Pass column family ID to table property collector
Summary: Pass column family ID through TablePropertiesCollectorFactory::CreateTablePropertiesCollector() so that users can identify which column family this file is for and handle it differently.

Test Plan: Add unit test scenarios in tests related to table properties collectors to verify the information passed in is correct.

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

Reviewed By: IslamAbdelRahman

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48411
2015-10-09 14:36:51 -07:00
sdong
000836a880 CompactionFilter::Context to contain column family ID
Summary: Add the column family ID to compaction filter context, so it is easier for compaction filter to apply different logic for different column families.

Test Plan: Add a unit test to verify the column family ID passed is correct.

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48357
2015-10-08 11:27:38 -07:00
Yueh-Hsuan Chiang
3a0bf873b5 Change RocksDB version to 4.1
Summary: Change RocksDB version to 4.1

Test Plan: no code change.

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D48387
2015-10-08 11:15:18 -07:00
Igor Canadi
9803e0d813 compaction_filter.h cleanup
Summary:
Two changes:
1. remove *V2 filter stuff. we deprecated that a while ago
2. clarify what happens when user sets max_subcompactions to bigger than 1

Test Plan: none

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47871
2015-10-08 09:32:50 -07:00
Islam AbdelRahman
51fa7ecec5 Bytes read/written from cache statistics
Summary: Add 2 new counters BLOCK_CACHE_BYTES_WRITE, BLOCK_CACHE_BYTES_READ to keep track of how many bytes were written to the cache and how many bytes that we read from cache

Test Plan: make check

Reviewers: sdong, yhchiang, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48195
2015-10-07 15:17:20 -07:00
dyniusz
a065cdb388 bloom hit/miss stats for SST and memtable
Summary:
	hit and miss bloom filter stats for memtable and SST
	stats added to perf_context struct
	key matches and prefix matches combined into one stat

Test Plan: unit test veryfing the functionality added, see BloomStatsTest in db_test.cc for details

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47859
2015-10-07 11:23:20 -07:00
Lakshmi Narayanan
4049bcde39 Added boolean variable to guard fallocate() calls
Summary:
Added boolean variable to guard fallocate() calls.
Set to false to prevent space leaks when tests fail.

Test Plan:
Compliles
Set to false and ran log device tests

Reviewers: sdong, lovro, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D48027
2015-10-07 10:04:05 -07:00
Igor Canadi
d80ce7f99a Compaction filter on merge operands
Summary:
Since Andres' internship is over, I took over https://reviews.facebook.net/D42555 and rebased and simplified it a bit.

The behavior in this diff is a bit simpler than in D42555:
* only merge operators are passed through FilterMergeValue(). If fitler function returns true, the merge operator is ignored
* compaction filter is *not* called on: 1) results of merge operations and 2) base values that are getting merged with merge operands (the second case was also true in previous diff)

Do we also need a compaction filter to get called on merge results?

Test Plan: make && make check

Reviewers: lovro, tnovak, rven, yhchiang, sdong

Reviewed By: sdong

Subscribers: noetzli, kolmike, leveldb, dhruba, sdong

Differential Revision: https://reviews.facebook.net/D47847
2015-10-07 09:30:03 -07:00
Islam AbdelRahman
9babaeed16 Update dump_tool and undump_tool to accept Options
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
2015-10-05 19:49:48 -07:00
Igor Canadi
115427ef63 Add APIs PauseBackgroundWork() and ContinueBackgroundWork()
Summary:
To support a new MongoDB capability, we need to make sure that we don't do any IO for a short period of time. For background, see:
* https://jira.mongodb.org/browse/SERVER-20704
* https://jira.mongodb.org/browse/SERVER-18899

To implement that, I add a new API calls PauseBackgroundWork() and ContinueBackgroundWork() which reuse the capability we already have in place for RefitLevel() function.

Test Plan: Added a new test in db_test. Made sure that test fails when PauseBackgroundWork() is commented out.

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47901
2015-10-02 13:17:34 -07:00
agiardullo
03b08ba9a9 Return MergeInProgress when fetching from transactions or WBWI with overwrite_key
Summary:
WriteBatchWithIndex::GetFromBatchAndDB only works correctly for overwrite_key=false.  Transactions use overwrite_key=true (since WriteBatchWithIndex::GetIteratorWithBase only works when overwrite_key=true).  So currently, Transactions could return incorrectly merged results when calling Get/GetForUpdate().

Until a permanent fix can be put in place, Transaction::Get[ForUpdate] and WriteBatchWithIndex::GetFromBatch[AndDB] will now return MergeInProgress if the most recent write to a key in the batch is a Merge.

Test Plan: more tests

Reviewers: sdong, yhchiang, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47817
2015-09-30 11:14:42 -07:00
Yueh-Hsuan Chiang
74b100ac17 RocksDB Options file format and its serialization / deserialization.
Summary:
This patch defines the format of RocksDB options file, which
follows the INI file format, and implements functions for its
serialization and deserialization.  An example RocksDB options
file can be found in examples/rocksdb_option_file_example.ini.

A typical RocksDB options file has three sections, which are
Version, DBOptions, and more than one CFOptions.  The RocksDB
options file in general follows the basic INI file format
with the following extensions / modifications:
 * Escaped characters
   We escaped the following characters:
    - \n -- line feed - new line
    - \r -- carriage return
    - \\ -- backslash \
    - \: -- colon symbol :
    - \# -- hash tag #
 * Comments
   We support # style comments.  Comments can appear at the ending
   part of a line.
 * Statements
   A statement is of the form option_name = value.
   Each statement contains a '=', where extra white-spaces
   are supported. However, we don't support multi-lined statement.
   Furthermore, each line can only contain at most one statement.
 * Section
   Sections are of the form [SecitonTitle "SectionArgument"],
   where section argument is optional.
 * List
   We use colon-separated string to represent a list.
   For instance, n1:n2:n3:n4 is a list containing four values.

Below is an example of a RocksDB options file:

[Version]
  rocksdb_version=4.0.0
  options_file_version=1.0
[DBOptions]
  max_open_files=12345
  max_background_flushes=301
[CFOptions "default"]
[CFOptions "the second column family"]
[CFOptions "the third column family"]

Test Plan: Added many tests in options_test.cc

Reviewers: igor, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: maykov, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46059
2015-09-29 14:42:40 -07:00
Igor Canadi
1eff1834b2 Remove non-existing functions. Closes #680
Summary: See https://github.com/facebook/rocksdb/issues/680

Test Plan: compiles

Reviewers: sdong, yhchiang, anthony

Reviewed By: anthony

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47721
2015-09-29 09:34:42 -07:00
agiardullo
afe0dc539b SingleDelete support for Transactions
Summary: Transactional SingleDelete is needed for MyRocks.  Note: This diff requires D47529.

Test Plan: Added some new tests in this diff as well as more tests added in D47529

Reviewers: rven, sdong, igor, yhchiang

Reviewed By: yhchiang

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47535
2015-09-28 12:14:26 -07:00
agiardullo
25fd743d75 Fix SingleDelete support in WriteBatchWithIndex
Summary: Fixed some  bugs in using SingleDelete on a WriteBatchWithIndex and added some tests.

Test Plan: new tests

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

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47529
2015-09-25 12:23:07 -07:00
Islam AbdelRahman
f03b5c987b Add experimental DB::AddFile() to plug sst files into empty DB
Summary:
This is an initial version of bulk load feature

This diff allow us to create sst files, and then bulk load them later, right now the restrictions for loading an sst file are
(1) Memtables are empty
(2) Added sst files have sequence number = 0, and existing values in database have sequence number = 0
(3) Added sst files values are not overlapping

Test Plan: unit testing

Reviewers: igor, ott, sdong

Reviewed By: sdong

Subscribers: leveldb, ott, dhruba

Differential Revision: https://reviews.facebook.net/D39081
2015-09-23 12:42:43 -07:00
sdong
f1b9f804e9 Add a mode to always pick the oldest file to compact for each level
Summary:
Add options.compaction_pri, which specifies the policy about which file to compact first.
kCompactionPriByLargestSeq will compact oldest files first.
Verified the behavior in db_bench but did not write unit tests yet. Also need to make it settable through option string and dynamically changeable.

Test Plan: Will write unit tests

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

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45951
2015-09-21 17:21:59 -07:00
Igor Canadi
199744f4c4 Merge pull request #728 from jsteemann/fix-missing-include-header
add missing header required for std::function
2015-09-21 19:50:00 +02:00
jsteemann
669b892f97 add missing header required for std::function
otherwise Visual Studio will have trouble compiling this file
2015-09-18 22:18:40 +02:00
jsteemann
624ef456dd fixed formatting. thanks @4tXJ7f for pointing me at make format 2015-09-18 22:03:47 +02:00
jsteemann
4704833357 pass input string to WriteBatch() by const reference
this may lead to copying less data (in case compilers don't
optimize away copying the string by themselves)
2015-09-18 20:20:32 +02:00
Andres Noetzli
014fd55adc Support for SingleDelete()
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
2015-09-17 11:42:56 -07:00
jsteemann
f8b770a942 fixed typos 2015-09-17 19:58:09 +02:00
Dmytro Okhonko
31a27a3606 Callback for informing backup downloading added
Summary:
In case of huge db backup infromation about progress of downloading would help.
New callback parameter in CreateNewBackup() function will trigger whenever a some amount of data downloaded.
Task: 8057631

Test Plan:
ProgressCallbackDuringBackup test that cover new functionality added to BackupableDBTest tests.
other test succeed as well.

Reviewers: Guenena, benj, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46575
2015-09-15 17:08:30 -07:00
Ari Ekmekji
2b683d4972 Add DBOption.max_subcompaction to option dump
Summary:
RocksDB options can be dumped to the log file, and
up to this point the max_subcompactions option was not included
in this dump. This fixes that.

Test Plan: makek all && make check

Reviewers: MarkCallaghan, igor, noetzli, anthony, yhchiang, sdong

Reviewed By: yhchiang, sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46971
2015-09-15 11:41:46 -07:00
Yoshinori Matsunobu
4886073174 Adding Slice::difference_offset() function
Summary:
There are some use cases in MyRocks to compare two slices
and to return the first byte where they differ. It may be
useful to add it as a RocksDB Slice function.

Test Plan: db_test

Reviewers: sdong, rven, igor

Reviewed By: igor

Subscribers: jkedgar, dhruba

Differential Revision: https://reviews.facebook.net/D46935
2015-09-15 10:32:42 -07:00
sdong
5de807ac16 Add options.hard_pending_compaction_bytes_limit to stop writes if compaction lagging behind
Summary: Add an option to stop writes if compaction lefts behind. If estimated pending compaction bytes is more than threshold specified by options.hard_pending_compaction_bytes_liimt, writes will stop until compactions are cleared to under the threshold.

Test Plan: Add unit test DBTest.HardLimit

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

Reviewed By: igor

Subscribers: MarkCallaghan, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D45999
2015-09-14 12:51:16 -07:00
Siying Dong
592f6bf782 Merge pull request #716 from yuslepukhin/refactor_file_reader_writer_win
Refactor to support file_reader_writer on Windows.
2015-09-14 12:29:01 -07:00
Ari Ekmekji
03ddce9a01 Add counters for L0 stall while L0-L1 compaction is taking place
Summary:
Although there are currently counters to keep track of the
stall caused by having too many L0 files, there is no distinction as
to whether when that stall occurs either (A) L0-L1 compaction is taking
place to try and mitigate it, or (B) no L0-L1 compaction has been scheduled
at the moment. This diff adds a counter for (A) so that the nature of L0
stalls can be better understood.

Test Plan: make all && make check

Reviewers: sdong, igor, anthony, noetzli, yhchiang

Reviewed By: yhchiang

Subscribers: MarkCallaghan, dhruba

Differential Revision: https://reviews.facebook.net/D46749
2015-09-14 11:03:37 -07:00