Reverse the order of updates to the same key in WriteBatchWithIndex #13387
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pdillinger
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Thanks for the review. Added release note. |
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Summary: added merge support for WBWIMemTable. Most of the preparation work is done in #13387 and #13400. The main code change to support merge is in wbwi_memtable.cc to support reading the Merge value type. The rest of the changes are mostly comment change and tests. Pull Request resolved: #13410 Test Plan: - new unit test - ran `python3 ./tools/db_crashtest.py --txn blackbox --txn_write_policy=0 --commit_bypass_memtable_one_in=100 --test_batches_snapshots=0 --use_merge=1` for several runs. Reviewed By: jowlyzhang Differential Revision: D69885868 Pulled By: cbi42 fbshipit-source-id: b127d95a3027dc35910f6e5d65f3409ba27e2b6b
ybtsdst
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…acebook#13387) Summary: as a preparation to support merge in [WBWIMemtable](https://github.com/facebook/rocksdb/blob/d48af213860054a7696e7ea2764f266c88a3263e/memtable/wbwi_memtable.h#L31), this PR updates how we [order updates to the same key](https://github.com/facebook/rocksdb/blob/d48af213860054a7696e7ea2764f266c88a3263e/utilities/write_batch_with_index/write_batch_with_index_internal.cc#L694-L697) in WriteBatchWithIndex. Specifically, the order is now reversed such that more recent update is ordered first. This will make iterating from WriteBatchWithIndex much easier since the key ordering in WBWI now matches internal key order where keys with larger sequence number are ordered first. The ordering is now explicitly documented above the declaration for `WriteBatchWithIndex` class. Places that use `WBWIIteratorImpl` and assume key ordering are updated. The rest is test and comments update. This will affect users who use WBWIIterator directly, the output of GetFromBatch, GetFromBatchAndDB or NewIteratorWithBase are not affected. Users are only affected if they may issue multiple updates to the same key. If WriteBatchWithIndex is created with `overwrite_key=true`, one the the updates needs to be Merge. Pull Request resolved: facebook#13387 Test Plan: we have some good coverage of WBWI, I updated some existing tests and added a test for `WBWIIteratorImpl`. Reviewed By: pdillinger Differential Revision: D69421268 Pulled By: cbi42 fbshipit-source-id: d97eec4ee74aeac3937c9758041c7713f07f9676
ybtsdst
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Apr 27, 2025
Summary: added merge support for WBWIMemTable. Most of the preparation work is done in facebook#13387 and facebook#13400. The main code change to support merge is in wbwi_memtable.cc to support reading the Merge value type. The rest of the changes are mostly comment change and tests. Pull Request resolved: facebook#13410 Test Plan: - new unit test - ran `python3 ./tools/db_crashtest.py --txn blackbox --txn_write_policy=0 --commit_bypass_memtable_one_in=100 --test_batches_snapshots=0 --use_merge=1` for several runs. Reviewed By: jowlyzhang Differential Revision: D69885868 Pulled By: cbi42 fbshipit-source-id: b127d95a3027dc35910f6e5d65f3409ba27e2b6b
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Summary: as a preparation to support merge in WBWIMemtable, this PR updates how we order updates to the same key in WriteBatchWithIndex. Specifically, the order is now reversed such that more recent update is ordered first. This will make iterating from WriteBatchWithIndex much easier since the key ordering in WBWI now matches internal key order where keys with larger sequence number are ordered first. The ordering is now explicitly documented above the declaration for
WriteBatchWithIndexclass.Places that use
WBWIIteratorImpland assume key ordering are updated. The rest is test and comments update.This will affect users who use WBWIIterator directly, the output of GetFromBatch, GetFromBatchAndDB or NewIteratorWithBase are not affected. Users are only affected if they may issue multiple updates to the same key. If WriteBatchWithIndex is created with
overwrite_key=true, one the the updates needs to be Merge.Test plan: we have some good coverage of WBWI, I updated some existing tests and added a test for
WBWIIteratorImpl.