Commit Graph

4 Commits

Author SHA1 Message Date
Cheng Chang
1b224324b5 Track WAL in MANIFEST: persist WALs to and recover WALs from MANIFEST (#7256)
Summary:
This PR makes it able to `LogAndApply` `VersionEdit`s related to WALs, and also be able to `Recover` from MANIFEST with WAL related `VersionEdit`s.

The `VersionEdit`s related to WAL are treated similarly as those related to column family operations, they are not applied to versions, but can be in a commit group. Mixing WAL related `VersionEdit`s with other types of edits will make logic in `ProcessManifestWrite` more complicated, so `VersionEdit`s related to WAL can either be WAL additions or deletions, like column family add and drop.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7256

Test Plan: a set of unit tests are added in `version_set_test.cc`

Reviewed By: riversand963

Differential Revision: D23123238

Pulled By: cheng-chang

fbshipit-source-id: 246be2ed4744fd03fa2738aba408aaa611d0379c
2020-10-23 22:49:51 -07:00
Akanksha Mahajan
b175eceb09 Store FSWritableFilePtr object in WritableFileWriter (#7193)
Summary:
Replace FSWritableFile pointer with FSWritableFilePtr
    object in WritableFileWriter.
    This new object wraps FSWritableFile pointer.

    Objective: If tracing is enabled, FSWritableFile Ptr returns
    FSWritableFileTracingWrapper pointer that includes all necessary
    information in IORecord and calls underlying FileSystem and invokes
    IOTracer to dump that record in a binary file. If tracing is disabled
    then, underlying FileSystem pointer is returned directly.
    FSWritableFilePtr wrapper class is added to bypass the
    FSWritableFileWrapper when
    tracing is disabled.

    Test Plan: make check -j64

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7193

Reviewed By: anand1976

Differential Revision: D23355915

Pulled By: akankshamahajan15

fbshipit-source-id: e62a27a13c1fd77e36a6dbafc7006d969bed25cf
2020-09-08 10:56:08 -07:00
Yanqin Jin
569b87e8c7 Fail recovery when MANIFEST record checksum mismatch (#6996)
Summary:
https://github.com/facebook/rocksdb/issues/5411 refactored `VersionSet::Recover` but introduced a bug, explained as follows.
Before, once a checksum mismatch happens, `reporter` will set `s` to be non-ok. Therefore, Recover will stop processing the MANIFEST any further.
```
// Correct
// Inside Recover
LogReporter reporter;
reporter.status = &s;
log::Reader reader(..., reporter);
while (reader.ReadRecord() && s.ok()) {
...
}
```
The bug is that, the local variable `s` in `ReadAndRecover` won't be updated by `reporter` while reading the MANIFEST. It is possible that the reader sees a checksum mismatch in a record, but `ReadRecord` retries internally read and finds the next valid record. The mismatched record will be ignored and no error is reported.
```
// Incorrect
// Inside Recover
LogReporter reporter;
reporter.status = &s;
log::Reader reader(..., reporter);
s = ReadAndRecover(reader, ...);

// Inside ReadAndRecover
  Status s;  // Shadows the s in Recover.
  while (reader.ReadRecord() && s.ok()) {
   ...
  }
```
`LogReporter` can use a separate `log_read_status` to track the errors while reading the MANIFEST. RocksDB can process more MANIFEST entries only if `log_read_status.ok()`.
Test plan (devserver):
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6996

Reviewed By: ajkr

Differential Revision: D22105746

Pulled By: riversand963

fbshipit-source-id: b22f717a423457a41ca152a242abbb64cf91fc38
2020-06-18 10:09:12 -07:00
Yanqin Jin
fb09ef05dc Attempt to recover from db with missing table files (#6334)
Summary:
There are situations when RocksDB tries to recover, but the db is in an inconsistent state due to SST files referenced in the MANIFEST being missing. In this case, previous RocksDB will just fail the recovery and return a non-ok status.
This PR enables another possibility. During recovery, RocksDB checks possible MANIFEST files, and try to recover to the most recent state without missing table file. `VersionSet::Recover()` applies version edits incrementally and "materializes" a version only when this version does not reference any missing table file. After processing the entire MANIFEST, the version created last will be the latest version.
`DBImpl::Recover()` calls `VersionSet::Recover()`. Afterwards, WAL replay will *not* be performed.
To use this capability, set `options.best_efforts_recovery = true` when opening the db. Best-efforts recovery is currently incompatible with atomic flush.

Test plan (on devserver):
```
$make check
$COMPILE_WITH_ASAN=1 make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6334

Reviewed By: anand1976

Differential Revision: D19778960

Pulled By: riversand963

fbshipit-source-id: c27ea80f29bc952e7d3311ecf5ee9c54393b40a8
2020-03-20 19:30:48 -07:00