mirror of
https://github.com/timescale/timescaledb.git
synced 2025-05-14 01:10:37 +08:00
e30699101b
The decision to add a minmax sparse index is made every time when the compressed chunk is created (full decompression followed by compression) based on the currently present indexes on the hypertable. No new chunk compression settings are added. No action is required on upgrade, but the feature is not enabled on existing chunks. The minmax index will be added when the chunk is fully decompressed and compressed. No action is required on downgrade, we ignore the unknown metadata columns. They will be removed when the chunk is fully decompressed and compressed. The potential drawback of this feature is increasing the storage requirements for the compressed chunk table, but it is normally only a few percent of the total compressed data size. It can be disabled with the GUC `timescaledb.auto_sparse_indexes`. Here's a small example of this feature in action: https://gist.github.com/akuzm/84d4b3b609e3581768173bd21001dfbf Note that the number of hit buffers is reduced almost 4x.
2 lines
104 B
Plaintext
2 lines
104 B
Plaintext
Implements: #6705 Add sparse minmax indexes for compressed columns that have uncompressed btree indexes
|