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Summary: As discussed in https://github.com/facebook/rocksdb/issues/11730 , this PR tracks the effective `full_history_ts_low` per SuperVersion and update existing sanity checks for `ReadOptions.timestamp >= full_history_ts_low` to use this per SuperVersion `full_history_ts_low` instead. This also means the check is moved to happen after acquiring SuperVersion. There are two motivations for this: 1) Each time `full_history_ts_low` really come into effect to collapse history, a new SuperVersion is always installed, because it would involve either a Flush or Compaction, both of which change the LSM tree shape. We can take advantage of this to ensure that as long as this sanity check is passed, even if `full_history_ts_low` can be concurrently increased and collapse some history above the requested `ReadOptions.timestamp`, a read request won’t have visibility to that part of history through this SuperVersion that it already acquired. 2) the existing sanity check uses `ColumnFamilyData::GetFullHistoryTsLow` without locking the db mutex, which is the mutex all `IncreaseFullHistoryTsLow` operation is using when mutating this field. So there is a race condition. This also solve the race condition on the read path. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11784 Test Plan: `make all check` // Checks success scenario really provide the read consistency attribute as mentioned above. `./db_with_timestamp_basic_test --gtest_filter=*FullHistoryTsLowSanityCheckPassReadIsConsistent*` // Checks failure scenario cleans up SuperVersion properly. `./db_with_timestamp_basic_test --gtest_filter=*FullHistoryTsLowSanityCheckFail*` `./db_secondary_test --gtest_filter=*FullHistoryTsLowSanityCheckFail*` `./db_readonly_with_timestamp_test --gtest_filter=*FullHistoryTsLowSanitchCheckFail*` Reviewed By: ltamasi Differential Revision: D48894795 Pulled By: jowlyzhang fbshipit-source-id: 1f801fe8e1bc8e63ca76c03cbdbd0974e5ff5bf6 |
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| .. | ||
| blob_compaction_filter.cc | ||
| blob_compaction_filter.h | ||
| blob_db.cc | ||
| blob_db.h | ||
| blob_db_gc_stats.h | ||
| blob_db_impl.cc | ||
| blob_db_impl.h | ||
| blob_db_impl_filesnapshot.cc | ||
| blob_db_iterator.h | ||
| blob_db_listener.h | ||
| blob_db_test.cc | ||
| blob_dump_tool.cc | ||
| blob_dump_tool.h | ||
| blob_file.cc | ||
| blob_file.h | ||