rocksdb

Commit Graph

Author	SHA1	Message	Date
Andrew Kryczka	c70bae1b05	Fix ConcurrentTaskLimiter token release for shutdown (#8253 ) Summary: Previously the shutdown process did not properly wait for all `compaction_thread_limiter` tokens to be released before proceeding to delete the DB's C++ objects. When this happened, we saw tests like "DBCompactionTest.CompactionLimiter" flake with the following error: ``` virtual rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl(): Assertion `outstanding_tasks_ == 0' failed. ``` There is a case where a token can still be alive even after the shutdown process has waited for BG work to complete. In particular, this happens because the shutdown process only waits for flush/compaction scheduled/unscheduled counters to all reach zero. These counters are decremented in `BackgroundCallCompaction()` functions. However, tokens are released in `BGWorkCompaction()` functions, which actually wrap the `BackgroundCallCompaction()` function. A simple sleep could repro the race condition: ``` $ diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc index 806bc548a..ba59efa89 100644 --- a/db/db_impl/db_impl_compaction_flush.cc +++ b/db/db_impl/db_impl_compaction_flush.cc @@ -2442,6 +2442,7 @@ void DBImpl::BGWorkCompaction(void arg) { static_cast<PrepickedCompaction*>(ca.prepicked_compaction); static_cast_with_check<DBImpl>(ca.db)->BackgroundCallCompaction( prepicked_compaction, Env::Priority::LOW); + sleep(1); delete prepicked_compaction; } $ ./db_compaction_test --gtest_filter=DBCompactionTest.CompactionLimiter db_compaction_test: util/concurrent_task_limiter_impl.cc:24: virtual rocksdb::ConcurrentTaskLimiterImpl::~ConcurrentTaskLimiterImpl(): Assertion `outstanding_tasks_ == 0' failed. Received signal 6 (Aborted) #0 /usr/local/fbcode/platform007/lib/libc.so.6(gsignal+0xcf) [0x7f02673c30ff] ?? ??:0 https://github.com/facebook/rocksdb/issues/1 /usr/local/fbcode/platform007/lib/libc.so.6(abort+0x134) [0x7f02673ac934] ?? ??:0 ... ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/8253 Test Plan: sleeps to expose race conditions Reviewed By: akankshamahajan15 Differential Revision: D28168064 Pulled By: ajkr fbshipit-source-id: 9e5167c74398d323e7975980c5cc00f450631160	4 years ago
sdong	fdf882ded2	Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433 ) Summary: When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433 Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag. Differential Revision: D19977691 fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e	5 years ago
Burton Li	46e3209e0d	Compaction limiter miscs (#4795 ) Summary: 1. Remove unused API SubtractCompactionTask(). 2. Assert outstanding tasks drop to zero in ConcurrentTaskLimiterImpl destructor. 3. Remove GetOutstandingTask() check from manual compaction test, as TEST_WaitForCompact() doesn't synced with 'delete prepicked_compaction' in DBImpl::BGWorkCompaction(), which may make the test flaky. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4795 Differential Revision: D13542183 Pulled By: siying fbshipit-source-id: 5eb2a47e62efe4126937149aa0df6e243ebefc33	6 years ago
Burton Li	a8b9891f95	Concurrent task limiter for compaction thread control (#4332 ) Summary: The PR is targeting to resolve the issue of: https://github.com/facebook/rocksdb/issues/3972#issue-330771918 We have a rocksdb created with leveled-compaction with multiple column families (CFs), some of CFs are using HDD to store big and less frequently accessed data and others are using SSD. When there are continuously write traffics going on to all CFs, the compaction thread pool is mostly occupied by those slow HDD compactions, which blocks fully utilize SSD bandwidth. Since atomic write and transaction is needed across CFs, so splitting it to multiple rocksdb instance is not an option for us. With the compaction thread control, we got 30%+ HDD write throughput gain, and also a lot smooth SSD write since less write stall happening. ConcurrentTaskLimiter can be shared with multi-CFs across rocksdb instances, so the feature does not only work for multi-CFs scenarios, but also for multi-rocksdbs scenarios, who need disk IO resource control per tenant. The usage is straight forward: e.g.: // // Enable compaction thread limiter thru ColumnFamilyOptions // std::shared_ptr<ConcurrentTaskLimiter> ctl(NewConcurrentTaskLimiter("foo_limiter", 4)); Options options; ColumnFamilyOptions cf_opt(options); cf_opt.compaction_thread_limiter = ctl; ... // // Compaction thread limiter can be tuned or disabled on-the-fly // ctl->SetMaxOutstandingTask(12); // enlarge to 12 tasks ... ctl->ResetMaxOutstandingTask(); // disable (bypass) thread limiter ctl->SetMaxOutstandingTask(-1); // Same as above ... ctl->SetMaxOutstandingTask(0); // full throttle (0 task) // // Sharing compaction thread limiter among CFs (to resolve multiple storage perf issue) // std::shared_ptr<ConcurrentTaskLimiter> ctl_ssd(NewConcurrentTaskLimiter("ssd_limiter", 8)); std::shared_ptr<ConcurrentTaskLimiter> ctl_hdd(NewConcurrentTaskLimiter("hdd_limiter", 4)); Options options; ColumnFamilyOptions cf_opt_ssd1(options); ColumnFamilyOptions cf_opt_ssd2(options); ColumnFamilyOptions cf_opt_hdd1(options); ColumnFamilyOptions cf_opt_hdd2(options); ColumnFamilyOptions cf_opt_hdd3(options); // SSD CFs cf_opt_ssd1.compaction_thread_limiter = ctl_ssd; cf_opt_ssd2.compaction_thread_limiter = ctl_ssd; // HDD CFs cf_opt_hdd1.compaction_thread_limiter = ctl_hdd; cf_opt_hdd2.compaction_thread_limiter = ctl_hdd; cf_opt_hdd3.compaction_thread_limiter = ctl_hdd; ... // // The limiter is disabled by default (or set to nullptr explicitly) // Options options; ColumnFamilyOptions cf_opt(options); cf_opt.compaction_thread_limiter = nullptr; Pull Request resolved: https://github.com/facebook/rocksdb/pull/4332 Differential Revision: D13226590 Pulled By: siying fbshipit-source-id: 14307aec55b8bd59c8223d04aa6db3c03d1b0c1d	6 years ago

4 Commits (8ea0a2c1bda4ccec63b5460df83648cede1b5eaf)