Summary:
New comment for share_files_with_checksum:
// Only used if share_table_files is set to true. Setting to false is
// DEPRECATED and potentially dangerous because in that case BackupEngine
// can lose data if backing up databases with distinct or divergent
// history, for example if restoring from a backup other than the latest,
// writing to the DB, and creating another backup. Setting to true (default)
// prevents these issues by ensuring that different table files (SSTs) with
// the same number are treated as distinct. See
// share_files_with_checksum_naming and ShareFilesNaming.
I have also removed interim option kFlagMatchInterimNaming, which is no
longer needed and was never needed for correct+compatible operation
(just performance).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8020
Test Plan:
tests updated. Backward+forward compatibility verified with
SHORT_TEST=1 check_format_compatible.sh. ldb uses default backup
options, and I manually verified shared_checksum in
/tmp/rocksdb_format_compatible_peterd/bak/current/ after run.
Reviewed By: ajkr
Differential Revision: D26786331
Pulled By: pdillinger
fbshipit-source-id: 36f968dfef1f5cacbd65154abe1d846151a55130
main
Peter Dillinger4 years agocommitted byFacebook GitHub Bot
* Fixed the truncation error found in APIs/tools when dumping block-based SST files in a human-readable format. After fix, the block-based table can be fully dumped as a readable file.
### Public API change
* Changed default `BackupableDBOptions::share_files_with_checksum` to `true` and deprecated `false` because of potential for data loss. Note that accepting this change in behavior can temporarily increase backup data usage because files are not shared between backups using the two different settings. Also removed obsolete option kFlagMatchInterimNaming.
* Add a new option BlockBasedTableOptions::max_auto_readahead_size. RocksDB does auto-readahead for iterators on noticing more than two reads for a table file if user doesn't provide readahead_size. The readahead starts at 8KB and doubles on every additional read upto max_auto_readahead_size and now max_auto_readahead_size can be configured dynamically as well. Found that 256 KB readahead size provides the best performance, based on experiments, for auto readahead. Experiment data is in PR #3282. If value is set 0 then no automatic prefetching will be done by rocksdb. Also changing the value will only affect files opened after the change.
* Add suppport to extend DB::VerifyFileChecksums API to also verify blob files checksum.
* When using the new BlobDB, the amount of data written by flushes/compactions is now broken down into table files and blob files in the compaction statistics; namely, Write(GB) denotes the amount of data written to table files, while Wblob(GB) means the amount of data written to blob files.