9358178edc
Summary: This PR allows RocksDB to run in single-primary, multi-secondary process mode. The writer is a regular RocksDB (e.g. an `DBImpl`) instance playing the role of a primary. Multiple `DBImplSecondary` processes (secondaries) share the same set of SST files, MANIFEST, WAL files with the primary. Secondaries tail the MANIFEST of the primary and apply updates to their own in-memory state of the file system, e.g. `VersionStorageInfo`. This PR has several components: 1. (Originally in #4745). Add a `PathNotFound` subcode to `IOError` to denote the failure when a secondary tries to open a file which has been deleted by the primary. 2. (Similar to #4602). Add `FragmentBufferedReader` to handle partially-read, trailing record at the end of a log from where future read can continue. 3. (Originally in #4710 and #4820). Add implementation of the secondary, i.e. `DBImplSecondary`. 3.1 Tail the primary's MANIFEST during recovery. 3.2 Tail the primary's MANIFEST during normal processing by calling `ReadAndApply`. 3.3 Tailing WAL will be in a future PR. 4. Add an example in 'examples/multi_processes_example.cc' to demonstrate the usage of secondary RocksDB instance in a multi-process setting. Instructions to run the example can be found at the beginning of the source code. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4899 Differential Revision: D14510945 Pulled By: riversand963 fbshipit-source-id: 4ac1c5693e6012ad23f7b4b42d3c374fecbe8886 |
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| .. | ||
| win | ||
| dirent.h | ||
| jemalloc_helper.h | ||
| likely.h | ||
| port_example.h | ||
| port_posix.cc | ||
| port_posix.h | ||
| port.h | ||
| README | ||
| stack_trace.cc | ||
| stack_trace.h | ||
| sys_time.h | ||
| util_logger.h | ||
| xpress.h | ||
This directory contains interfaces and implementations that isolate the rest of the package from platform details. Code in the rest of the package includes "port.h" from this directory. "port.h" in turn includes a platform specific "port_<platform>.h" file that provides the platform specific implementation. See port_posix.h for an example of what must be provided in a platform specific header file.