afad5bd1c5
Summary: The call stack used to look like this during static initialization: #0 0x00000000008032d1 in rocksdb::ThreadLocalPtr::StaticMeta::StaticMeta() (this=0x7ffff683b300) at util/thread_local.cc:172 #1 0x00000000008030a7 in rocksdb::ThreadLocalPtr::Instance() () at util/thread_local.cc:135 #2 0x000000000080310f in rocksdb::ThreadLocalPtr::StaticMeta::Mutex() () at util/thread_local.cc:141 #3 0x0000000000803103 in rocksdb::ThreadLocalPtr::StaticMeta::InitSingletons() () at util/thread_local.cc:139 #4 0x000000000080305d in rocksdb::ThreadLocalPtr::InitSingletons() () at util/thread_local.cc:106 It involves outer/inner classes and the call stacks goes outer->inner->outer->inner, which is too difficult to understand. We can avoid a level of back-and-forth by skipping StaticMeta::InitSingletons(), which doesn't initialize anything beyond what ThreadLocalPtr::Instance() already initializes. Now the call stack looks like this during static initialization: #0 0x00000000008032c5 in rocksdb::ThreadLocalPtr::StaticMeta::StaticMeta() (this=0x7ffff683b300) at util/thread_local.cc:170 #1 0x00000000008030a7 in rocksdb::ThreadLocalPtr::Instance() () at util/thread_local.cc:135 #2 0x000000000080305d in rocksdb::ThreadLocalPtr::InitSingletons() () at util/thread_local.cc:106 Test Plan: unit tests verify StaticMeta::mutex_ is still initialized in DefaultEnv() (StaticMeta::mutex_ is the only variable intended to be initialized via StaticMeta::InitSingletons() which I removed) #0 0x00000000005cee17 in rocksdb::port::Mutex::Mutex(bool) (this=0x7ffff69500b0, adaptive=false) at port/port_posix.cc:52 #1 0x0000000000769cf8 in rocksdb::ThreadLocalPtr::StaticMeta::StaticMeta() (this=0x7ffff6950000) at util/thread_local.cc:168 #2 0x0000000000769a53 in rocksdb::ThreadLocalPtr::Instance() () at util/thread_local.cc:133 #3 0x0000000000769a09 in rocksdb::ThreadLocalPtr::InitSingletons() () at util/thread_local.cc:105 #4 0x0000000000647d98 in rocksdb::Env::Default() () at util/env_posix.cc:845 Reviewers: lightmark, yhchiang, sdong Reviewed By: sdong Subscribers: arahut, IslamAbdelRahman, yiwu, andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60813
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it specially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/