f6fd4b9dbd
Summary: It's been relatively easy to break our stack trace printer: * If another thread reaches a signal condition such as a related SEGV or assertion failure while one is trying to print a stack trace from the signal handler, it seems to end the process abruptly without a stack trace. * If the process exits normally in one thread (such as main finishing) while another is trying to print a stack trace from the signal handler, it seems the process will often end normally without a stack trace. This change attempts to fix these issues, with * Keep the custom signal handler installed as long as possible, so that other threads will most likely re-enter our custom handler. (We only switch back to default for triggering core dump or whatever after stack trace.) * Use atomics and sleeps to implement a crude recursive mutex for ensuring all threads hitting the custom signal handler wait on the first that is trying to print a stack trace, while recursive signals in the same thread can still be handled cleanly. * Use an atexit handler to hook into normal exit to (a) wait on a pending printing of stack trace when detectable and applicable, and (b) detect and warn when printing a stack trace might be interrupted by a process exit in progress. (I don't know how to pause that *after* our atexit handler has been called; the best I know how to do is warn, "In a race with process already exiting...".) Pull Request resolved: https://github.com/facebook/rocksdb/pull/12086 Test Plan: manual, including with TSAN. I added this code to the end of a unit test file: ``` for (size_t i = 0; i < 3; ++i) { std::thread t([]() { assert(false); }); t.detach(); } ``` Followed by either `sleep(100)` or `usleep(100)` or usual process exit. And for recursive signal testing, inject `abort()` at various places in the handler. Reviewed By: cbi42 Differential Revision: D51531882 Pulled By: pdillinger fbshipit-source-id: 3473b863a43e61b722dfb7a2ed12a8120949b09c |
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README.md
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 especially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/main/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.
Questions and discussions are welcome on the RocksDB Developers Public Facebook group and email list on Google Groups.
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.