Summary:
When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue.
The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction.
Here are the performance results:
Command:
./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333
Before the patch:
fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s
After the patch:
fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s
Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got:
fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s
Test Plan:
make check
two stress tests:
Big number of compactions and flushes:
./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000
max_background_flushes=0, to verify that this case also works correctly
./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000
Reviewers: ljin, rven, yhchiang, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D30123
Summary: Avoid unnecessary unlock and lock mutex when notifying events.
Test Plan: ./listener_test
Reviewers: igor
Reviewed By: igor
Subscribers: sdong, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D30267
Summary:
We now release the mutex before copying the files in the case
of the trivial move. This path does not use the compaction job.
Test Plan: DBTest.LevelCompactionThirdPath
Reviewers: yhchiang, igor, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D30381
Summary:
Allow Level-style compaction to place files in different paths
This diff provides the code for task 4854591. We now support level-compaction
to place files in different paths by specifying them in db_paths along with
the minimum level for files to store in that path.
Test Plan: ManualLevelCompactionOutputPathId in db_test.cc
Reviewers: yhchiang, MarkCallaghan, dhruba, yoshinorim, sdong
Reviewed By: sdong
Subscribers: yoshinorim, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D29799
Summary: Now DB::GetSnapshot() doesn't scale to more column families, as it needs to go through all the column families to find whether snapshot is supported. This patch optimizes it.
Test Plan:
Add unit tests to cover negative cases.
make all check
Reviewers: yhchiang, rven, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D30093
Summary: This is a regression bug introduced by https://reviews.facebook.net/D24729 . max_total_wal_size would be off the target it should be more and more in the case that the a user holds the current super version after flush or compaction. This patch fixes it
Test Plan: make all check
Reviewers: yhchiang, rven, igor
Reviewed By: igor
Subscribers: ljin, yoshinorim, MarkCallaghan, hermanlee4, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D29961
Summary:
Add a counter in SnapshotList to show number of snapshots. Also a unix timestamp in every snapshot.
Add two DB Properties to return number of snapshots and timestamp of the oldest one.
Test Plan: Add unit test checking
Reviewers: yhchiang, rven, igor
Reviewed By: igor
Subscribers: leveldb, dhruba, MarkCallaghan
Differential Revision: https://reviews.facebook.net/D29919
Summary:
Introduces a new class for managing write buffer memory across column
families. We supplement ColumnFamilyOptions::write_buffer_size with
ColumnFamilyOptions::write_buffer, a shared pointer to a WriteBuffer
instance that enforces memory limits before flushing out to disk.
Test Plan: Added SharedWriteBuffer unit test to db_test.cc
Reviewers: sdong, rven, ljin, igor
Reviewed By: igor
Subscribers: tnovak, yhchiang, dhruba, xjin, MarkCallaghan, yoshinorim
Differential Revision: https://reviews.facebook.net/D22581
Summary:
In some environment such as android, the c++ library does not have
std::to_string. This path adds rocksdb::ToString(), which wraps std::to_string
when std::to_string is not available, and implements std::to_string
in the other case.
Test Plan:
make dbg -j32
./db_test
make clean
make dbg OPT=-DOS_ANDROID -j32
./db_test
Reviewers: ljin, sdong, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D29181
Summary:
An entry of ConstantColumnFamilyInfo is created when:
1. DB::Open
2. CreateColumnFamily.
However, there are cases that DB::Open could also call CreateColumnFamily
when create_missing_column_families=true. As a result, it will create
duplicate ConstantColumnFamilyInfo and one of them would be leaked.
Test Plan: ./deletefile_test
Reviewers: igor, sdong, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D29307
Summary:
Add enable_thread_tracking to DBOptions to allow
tracking thread status related to the DB. Default is off.
Test Plan:
export ROCKSDB_TESTS=ThreadList
./db_test
Reviewers: ljin, sdong, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D29289
Summary:
Add GetThreadList API, which allows developer to track the
status of each process. Currently, calling GetThreadList will
only get the list of background threads in RocksDB with their
thread-id and thread-type (priority) set. Will add more support
on this in the later diffs.
ThreadStatus currently has the following properties:
// An unique ID for the thread.
const uint64_t thread_id;
// The type of the thread, it could be ROCKSDB_HIGH_PRIORITY,
// ROCKSDB_LOW_PRIORITY, and USER_THREAD
const ThreadType thread_type;
// The name of the DB instance where the thread is currently
// involved with. It would be set to empty string if the thread
// does not involve in any DB operation.
const std::string db_name;
// The name of the column family where the thread is currently
// It would be set to empty string if the thread does not involve
// in any column family.
const std::string cf_name;
// The event that the current thread is involved.
// It would be set to empty string if the information about event
// is not currently available.
Test Plan:
./thread_list_test
export ROCKSDB_TESTS=GetThreadList
./db_test
Reviewers: rven, igor, sdong, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D25047
Summary: This way we can gurantee that old MemTables get destructed before DBImpl gets destructed, which might be useful if we want to make them depend on state from DBImpl.
Test Plan: make check with asserts in JobContext's destructor
Reviewers: ljin, sdong, yhchiang, rven, jonahcohen
Reviewed By: jonahcohen
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28959
Summary: As a short-term fix, let's go back to previous way of calculating NeedsCompaction(). SIGSEGV happens because NeedsCompaction() can happen before super_version (and thus MutableCFOptions) is initialized.
Test Plan: make check
Reviewers: ljin, sdong, rven, yhchiang
Reviewed By: yhchiang
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28875
Summary:
Move NeedsCompaction() from VersionStorageInfo to CompactionPicker
to allow different compaction strategy to have their own way to
determine whether doing compaction is necessary.
When compaction style is set to kCompactionStyleNone, then
NeedsCompaction() will always return false.
Test Plan:
export ROCKSDB_TESTS=Compact
./db_test
Reviewers: ljin, sdong, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28719
Summary: So iOS size_t is 32-bit, so we need to static_cast<size_t> any uint64_t :(
Test Plan: TARGET_OS=IOS make static_lib
Reviewers: dhruba, ljin, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28743
Summary:
We need to turn on -Wshorten-64-to-32 for mobile. See D1671432 (internal phabricator) for details.
This diff turns on the warning flag and fixes all the errors. There were also some interesting errors that I might call bugs, especially in plain table. Going forward, I think it makes sense to have this flag turned on and be very very careful when converting 64-bit to 32-bit variables.
Test Plan: compiles
Reviewers: ljin, rven, yhchiang, sdong
Reviewed By: yhchiang
Subscribers: bobbaldwin, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28689
Summary: I mistakenly changed the behavior to ++next_file_number_ instead of next_file_number_++, as it should have been: 344edbb044/db/version_set.h (L539)
Test Plan: none. not sure if this would break anything. It's just different behavior, so I'd rather not risk
Reviewers: ljin, rven, yhchiang, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28557
Summary: Based on @sdong's feedback in the diff, we shouldn't keep db_mutex in CompactionJob's state. This diff removes db_mutex from CompactionJob state, by making next_file_number_ atomic. That way we only need to pass the lock to InstallCompactionResults() because of LogAndApply()
Test Plan: make check
Reviewers: ljin, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: sdong, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28491
Summary:
This diff adds three sets of APIs to RocksDB.
= GetColumnFamilyMetaData =
* This APIs allow users to obtain the current state of a RocksDB instance on one column family.
* See GetColumnFamilyMetaData in include/rocksdb/db.h
= EventListener =
* A virtual class that allows users to implement a set of
call-back functions which will be called when specific
events of a RocksDB instance happens.
* To register EventListener, simply insert an EventListener to ColumnFamilyOptions::listeners
= CompactFiles =
* CompactFiles API inputs a set of file numbers and an output level, and RocksDB
will try to compact those files into the specified level.
= Example =
* Example code can be found in example/compact_files_example.cc, which implements
a simple external compactor using EventListener, GetColumnFamilyMetaData, and
CompactFiles API.
Test Plan:
listener_test
compactor_test
example/compact_files_example
export ROCKSDB_TESTS=CompactFiles
db_test
export ROCKSDB_TESTS=MetaData
db_test
Reviewers: ljin, igor, rven, sdong
Reviewed By: sdong
Subscribers: MarkCallaghan, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D24705
Summary:
Here's a prototype of redesigning pending_outputs_. This way, we don't have to expose pending_outputs_ to other classes (CompactionJob, FlushJob, MemtableList). DBImpl takes care of it.
Still have to write some comments, but should be good enough to start the discussion.
Test Plan: make check, will also run stress test
Reviewers: ljin, sdong, rven, yhchiang
Reviewed By: yhchiang
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28353
Summary: as title
Test Plan: ./db_test
Reviewers: sdong, yhchiang, rven, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28269
Summary: as title
Test Plan: ran it
Reviewers: yhchiang, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28311
Summary: Apply InfoLogLevel to the logs in db/db_impl.cc
Test Plan:
db_test
db_bench
Reviewers: ljin, sdong, igor
Reviewed By: igor
Subscribers: leveldb, MarkCallaghan, dhruba
Differential Revision: https://reviews.facebook.net/D28233
Summary: Enforce the accessier naming convention in functions in version_set.h
Test Plan: make all check
Reviewers: ljin, yhchiang, rven, igor
Reviewed By: igor
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D28143
Summary:
With the patch, thread pool size will be automatically increased if DB's options ask for more parallelism of compactions or flushes.
Too many users have been confused by the API. Change it to make it harder for users to make mistakes
Test Plan: Add two unit tests to cover the function.
Reviewers: yhchiang, rven, igor, MarkCallaghan, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27555
Summary:
Long awaited CompactionJob class! Move most compaction-related things from DBImpl to CompactionJob, making CompactionJob easier to test and understand.
Currently this is just replicating exactly the same functionality with as little as change as possible. As future work, we should:
1. Add CompactionJob tests (I think I'll do that tomorrow)
2. Reduce CompactionJob's state that it inherits from DBImpl
3. Figure out how to do yielding to flush better. Currently I implemented a callback as we agreed yesterday, but I don't think it's a good long term solution.
This reduces db_impl.cc from 5000+ LOC to 3400!
Test Plan: make check, will add CompactionJob-specific tests, probably also move some tests from db_test to compaction_job_test
Reviewers: rven, yhchiang, sdong, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27957
Summary:
...and fix all the errors :)
Jim suggested turning on -Wshadow because it helped him fix number of critical bugs in fbcode. I think it's a good idea to be -Wshadow clean.
Test Plan: compiles
Reviewers: yhchiang, rven, sdong, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27711
Summary:
Rename Version::Builder to VersionBuilder and expose its definition to a header.
Make VerisonBuilder not reference Version or ColumnFamilyData, only working with VersionStorageInfo.
Add version_builder_test which has a simple test.
Test Plan: make all check
Reviewers: rven, yhchiang, igor, ljin
Reviewed By: igor
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D27969
Summary: Decoupling code that deals with archived log files outside of DBImpl. That will make this code easier to reason about and test. It will also make the code easier to improve, because an improver doesn't have to understand DBImpl code in entirety.
Test Plan: added test
Reviewers: ljin, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27873
Summary:
Make compaction picker easier to test.
The basic idea is to separate a minimum subcomponent of Version to VersionStorageInfo, which just responsible to LSM tree. A stub VersionStorageInfo can then be easily created and passed into compaction picker so that we can check the outputs.
It now passes most tests. Still two things need to be done:
(1) deal with the FIFO compaction's file size.
(2) write an example test to make sure the interface can do the job.
Add a compaction_picker_test to make sure compaction picker codes can be easily unit tested.
Test Plan:
Pass all unit tests and compaction_picker_test
Reviewers: yhchiang, rven, igor, ljin
Reviewed By: ljin
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D27639
Summary:
This diff has two fixes.
1. Fix the bug where compaction does not fail when RocksDB can't create a new file.
2. When NewWritableFiles() fails in OpenCompactionOutputFiles(), previously such fail-to-created file will be still be included as a compaction output. This patch also fixes this bug.
3. Allow VersionEdit::EncodeTo() to return Status and add basic check.
Test Plan:
./version_edit_test
export ROCKSDB_TESTS=FileCreationRandomFailure
./db_test
Reviewers: ljin, sdong, nkg-, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D25581
Summary:
Abstract out FlushProcess and take it out of DBImpl.
This also includes taking DeletionState outside of DBImpl.
Currently this diff is only doing the refactoring. Future work includes:
1. Decoupling flush_process.cc, make it depend on less state
2. Write flush_process_test, which will mock out everything that FlushProcess depends on and test it in isolation
Test Plan: make check
Reviewers: rven, yhchiang, sdong, ljin
Reviewed By: ljin
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27561
Summary: RocksDB already depends on C++11, so we might as well all the goodness that C++11 provides. This means that we don't need AtomicPointer anymore. The less things in port/, the easier it will be to port to other platforms.
Test Plan: make check + careful visual review verifying that NoBarried got memory_order_relaxed, while Acquire/Release methods got memory_order_acquire and memory_order_release
Reviewers: rven, yhchiang, ljin, sdong
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D27543
Summary:
Make inplace_update_support and inplace_update_num_locks dynamic.
inplace_callback becomes immutable
We are almost free of references to cfd->options() in db_impl
Test Plan: unit test
Reviewers: igor, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D25293
Summary: as title
Test Plan: unit test
Reviewers: sdong, yhchiang, rven, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D25347
Summary:
This is not a critical options. Making it dynamic so that we can remove
more reference to cfd->options()
Test Plan: unit test
Reviewers: yhchiang, sdong, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24957
Summary: It is useful to print out number of keys in DB Stats
Test Plan:
./db_bench --benchmarks fillrandom --num 1000000 -threads 16 -batch_size=16
and watch the outputs in LOG files
Reviewers: MarkCallaghan, ljin, yhchiang, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24513
Summary:
DeleteFile() call was broken for non-default column family. This fixes it. We might need this feature for mongo.
I also introduced a possibility of deleting oldest file in level 0.
Test Plan: added unit test to deletefile_test
Reviewers: ljin, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24909
Summary: as title
Test Plan: make release
Reviewers: sdong, yhchiang, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24903
Summary: Add more tests as well
Test Plan: unit test
Reviewers: igor, sdong, yhchiang
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24747
Summary: as title
Test Plan: unit test
Reviewers: sdong, yhchiang, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D24729
