A Smooth Sea Never Made a Skillful Sailor

This is a new series of articles covering short "Today I learned" topics as I peel the layers on CockroachDB. This is meant to resemble release notes. I decided to mix it up with the format for these posts as they may not justify an entire blog. Previous articles Volume 1 Volume 2 Volume 3 Volume 4 Volume 5 Volume 6 Volume 7 Topics Topic 1 Reset network and execution statistics in CLI This topic will cover what trivial misconfigurations may lead to if you don't keep client and server versions uniform. These mismatched versions may lead to unforseen consequences. This is one of those situations where a user reported missing info from their CLI. In this case, they were missing execution and network latency which we conveniently output after every query artem @free - tier.gcp - us - central1.cockroachlabs.cloud: 26257 / defaultdb > select * from results limit 1 ; id | city | type | owner...

This is a new series of articles covering short "Today I learned" topics as I peel the layers on CockroachDB. This is meant to resemble release notes. I decided to mix it up with the format for these posts as they may not justify an entire blog. Previous articles Volume 1 Volume 2 Volume 3 Volume 4 Volume 5 Volume 6 Volume 7 Topics Topic 1 Force lookup join instead of merge or hash join set prefer_lookup_joins_for_fks = on ; show prefer_lookup_joins_for_fks; prefer_lookup_joins_for_fks ------------------------------- on To make the optimizer prefer lookup joins over merge or hash joins when performing foreign key checks, set the prefer_lookup_joins_for_fks session variable to on (merge joins are the default for single row inserts and hash joins are likely to appear with more rows. There are times when a lookup join will be more efficient than the chosen plan by the optimizer. Lesson here is to test all available options and not to accept the d...