When Good Correlation is Not Enough (hakibenita.com)
from tedu@inks.tedunangst.com to inks@inks.tedunangst.com on 28 Jul 2023 02:39
https://inks.tedunangst.com/l/5015

Choosing to use a block range index (BRIN) to query a field with high correlation is a no-brainer for the optimizer. The small size of the index and the field’s correlation makes BRIN an ideal choice. However, a recent event taught us that correlation can be misleading. Under some easily reproducible circumstances, a BRIN index can result in significantly slower execution even when the indexed field has very high correlation.

#database #development #perf #sql

#database #development #perf #sql