Custom vs generic plan
Postgres FM · Nikolay Samokhvalov and Michael Christofides
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Show Notes
Nikolay and Michael discuss custom and generic planning in prepared statements — how it works, how issues can present themselves, some ways to view the generic plan, and some benefits of avoiding planning (not just time).
Here are some links to things they mentioned:
- PREPARE https://www.postgresql.org/docs/current/sql-prepare.html
- track_activity_query_size https://www.postgresql.org/docs/current/runtime-config-statistics.html#GUC-TRACK-ACTIVITY-QUERY-SIZE
- plan_cache_mode https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-PLAN-CACHE-MODE
- EXPLAIN (GENERIC_PLAN) https://www.postgresql.org/docs/current/sql-explain.html#id-1.9.3.148.8
- EXPLAIN (GENERIC_PLAN) in PostgreSQL 16 (blog post by Laurenz from Cybertec) https://www.cybertec-postgresql.com/en/explain-generic-plan-postgresql-16/
- Running EXPLAIN on any query, even with $1 parameters (blog post and video by Lukas Fittl of pganalyze) https://pganalyze.com/blog/5mins-postgres-explain-generic-plan
- EXPLAIN from pg_stat_statements, how to get the generic plan (blog post by Franck Pashto of Yugabyte) https://dev.to/yugabyte/explain-from-pgstatstatements-normalized-queries-how-to-always-get-the-generic-plan-in--5cfi
- Rework query relation permission checking (commit by Amit Langote) https://git.postgresql.org/gitweb/postgres.git?p=postgresql.git;a=commit;h=a61b1f74823c9c4f79c95226a461f1e7a367764b
- Partition pruning, prepared statements and generic vs custom query plans (a follow up blog post and video by Lukas) https://pganalyze.com/blog/5mins-postgres-partition-pruning-prepared-statements-generic-vs-custom-query-plans
- Our episode on over-indexing (inc LWLock discussion) https://postgres.fm/episodes/over-indexing
- “The year of the lock manager’s revenge” (from blog post by Jeremy Schneider) https://ardentperf.com/2024/03/03/postgres-indexes-partitioning-and-lwlocklockmanager-scalability/
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What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!
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Postgres FM is brought to you by:
- Nikolay Samokhvalov, founder of Postgres.ai
- Michael Christofides, founder of pgMustard
With special thanks to:
- Jessie Draws for the amazing artwork