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> LMDB writes will keep data exactly where it was placed the first time it was written. Wait a minute. I was under the impression that the reason LMDB works so
by rakoo 11y ago
> LMDB writes will keep data exactly where it was placed the first time it was written.
Wait a minute. I was under the impression that the reason LMDB works so well under concurrent access is that it _never_ modifies anything in place, but when it has to modify a value it will copy the existing content of the page along with the new value to some unused place... so data _is_ moved between updates.
Or am I missing something ?
- biokoda 11y agoYou understand correctly. My point was LMDB does not have checkpoints/compaction steps where it "silently" in the background copies data around. When writes are large, this is an important point. LevelDB/RocksDB type stores work great for small values, but perform very poorly for large writes because they copy data around in compaction steps.