triggerTSDBCompaction

Syntax

triggerTSDBCompaction(chunkId, [level=0])

Arguments

chunkId is a STRING scalar indicating the chunk ID.

level (optional) specifies at which level the compaction is triggered. It can be an integer in [-1,3].

  • If level is an integer in [0,3], compaction is triggered at the specified level. The default value is 0.
  • When level = -1, all level files are compacted into a single level file.

Details

Use this command to manually trigger the compaction of TSDB level files at specific level for optimal reading performance.

Note: The compaction of level 3 files can only be performed when configuration parameter allowTSDBLevel3Compaction is set to true and for tables with keepDuplicates=FIRST/LAST specified.

Examples

There are 2 file types in a chunk, the file chunk containing information about the database and table schema, and the tablet chunk storing data. Compaction of level files can only be conducted within a tablet chunk. Set "type=1" to filter the IDs of tablet chunks.

chunkIds = exec chunkId from getChunksMeta() where type=1
for (x in chunkIds) {
    triggerTSDBCompaction(x)
}