-
Notifications
You must be signed in to change notification settings - Fork 6.3k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Make it able to ignore WAL related VersionEdits in older versions (#7873
) Summary: Although the tags for `WalAddition`, `WalDeletion` are after `kTagSafeIgnoreMask`, to actually be able to skip these entries in older versions of RocksDB, we require that they are encoded with their encoded size as the prefix. This requirement is not met in the current codebase, so a downgraded DB may fail to open if these entries exist in the MANIFEST. If a DB wants to downgrade, and its MANIFEST contains `WalAddition` or `WalDeletion`, it can set `track_and_verify_wals_in_manifest` to `false`, then restart twice, then downgrade. On the first restart, a new MANIFEST will be created with a `WalDeletion` indicating that all previously tracked WALs are removed from MANIFEST. On the second restart, since there is no tracked WALs in MANIFEST now, a new MANIFEST will be created with neither `WalAddition` nor `WalDeletion`. Then the DB can downgrade. Tags for `BlobFileAddition`, `BlobFileGarbage` also have the same problem, but this PR focuses on solving the problem for WAL edits. Pull Request resolved: #7873 Test Plan: Added a `VersionEditTest::IgnorableTags` unit test to verify all entries with tags larger than `kTagSafeIgnoreMask` can actually be skipped and won't affect parsing of other entries. Reviewed By: ajkr Differential Revision: D25935930 Pulled By: cheng-chang fbshipit-source-id: 7a02fdba4311d6084328c14aed110a26d08c3efb
- Loading branch information
1 parent
928dea0
commit e449482
Showing
3 changed files
with
142 additions
and
18 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters