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bytedance / terarkdb

A RocksDB compatible KV storage engine with better performance
Apache License 2.0
2.05k stars 202 forks source link

About max subcompaction and blob size #262

Closed zhougit86 closed 1 year ago

zhougit86 commented 1 year ago

@yapple Master, I have 2 questions: 1, what's the reason terark set the max subcompaction to 1 even when the config is 0 2, what's the unit size of blob size? kb mb? and the size is counted after zstd/ snappy compression or before it?

yapple commented 1 year ago
  1. subcompaction should be >= 1, it meaning a compaction job will partition to how many sub compaction jobs
  2. blob_size 's unit is byte, it meaning the threshold of value lenth to triiger kv separation
zhougit86 commented 1 year ago

if subcompaction == 1, that means only one "major" compaction will happen? no concurrent subcompaction?