95b41eec6d
Summary: The RocksDB correctness testing has recently discovered a possible, but very unlikely, correctness issue with MultiGet. The issue happens when all of the below conditions are met - 1. Duplicate keys in a MultiGet batch 2. Key matches the last key in a non-zero, non-bottommost level file 3. Final value is not in the file (merge operand, not snapshot visible etc) 4. Multiple entries exist for the key in the file spanning more than 1 data block. This can happen due to snapshots, which would force multiple versions of the key in the file, and they may spill over to another data block 5. Lookup attempt in the SST for the first of the duplicates fails with IO error on a data block (NOT the first data block, but the second or subsequent uncached block), but no errors for the other duplicates 6. Value or merge operand for the key is present in the very next level The problem is, in FilePickerMultiGet, when looking up keys in a level we use FileIndexer and the overlapping file in the current level to determine the search bounds for that key in the file list in the next level. If the next level is empty, the search bounds are reset and we do a full binary search in the next non-empty level's LevelFilesBrief. However, under the conditions https://github.com/facebook/rocksdb/issues/1 and https://github.com/facebook/rocksdb/issues/2 listed above, only the first of the duplicates has its next-level search bounds updated, and the remaining duplicates are skipped. Pull Request resolved: https://github.com/facebook/rocksdb/pull/12295 Test Plan: Add unit tests that fail an assertion or return wrong result without the fix Reviewed By: hx235 Differential Revision: D53187634 Pulled By: anand1976 fbshipit-source-id: a5eadf4fede9bbdec784cd993b15e3341436d1ea |
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| buckifier | ||
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| cmake | ||
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| db | ||
| db_stress_tool | ||
| docs | ||
| env | ||
| examples | ||
| file | ||
| fuzz | ||
| include/rocksdb | ||
| java | ||
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| microbench | ||
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| options | ||
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| table | ||
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| util | ||
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| AUTHORS | ||
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| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| COPYING | ||
| DEFAULT_OPTIONS_HISTORY.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| LANGUAGE-BINDINGS.md | ||
| LICENSE.Apache | ||
| LICENSE.leveldb | ||
| Makefile | ||
| PLUGINS.md | ||
| README.md | ||
| TARGETS | ||
| USERS.md | ||
| Vagrantfile | ||
| WINDOWS_PORT.md | ||
| common.mk | ||
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| issue_template.md | ||
| rocksdb.pc.in | ||
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README.md
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key-value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it especially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/main/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Questions and discussions are welcome on the RocksDB Developers Public Facebook group and email list on Google Groups.
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.