Slow count

Nikolay and Michael discuss why counting can be slow in Postgres, and what the options are for counting things quickly at scale. Here are some links to things they mentioned:Aggregate functions (docs) https://www.postgresql.org/docs/current/functions-aggregate.htmlPostgREST https://github.com/PostgREST/postgrest Get rid of count by default in PostgREST https://github.com/PostgREST/postgrest/issues/273 Faster PostgreSQL Counting (by Joe Nelson on the Citus blog) https://www.citusdata.com/blog/2016/10/12/count-performance Our episode on Index-Only Scans https://postgres.fm/episodes/index-only-scansPostgres HyperLogLog https://github.com/citusdata/postgresql-hllOur episode on Row estimates https://postgres.fm/episodes/row-estimates Our episode about dangers of NULLs https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknown Aggregate expressions, including FILTER https://www.postgresql.org/docs/current/sql-expressions.html#SYNTAX-AGGREGATESSpread writes for counter cache (tip from Tobias Petry) https://x.com/tobias_petry/status/1475870220422107137pg_ivm extension (Incremental View Maintenance) https://github.com/sraoss/pg_ivm pg_duckdb announcement https://motherduck.com/blog/pg_duckdb-postgresql-extension-for-duckdb-motherduckOur episode on Queues in Postgres https://postgres.fm/episodes/queues-in-postgresOur episode on Real-time analytics https://postgres.fm/episodes/real-time-analyticsClickHouse acquired PeerDB https://clickhouse.com/blog/clickhouse-acquires-peerdb-to-boost-real-time-analytics-with-postgres-cdc-integrationTimescale Continuous Aggregates https://www.timescale.com/blog/materialized-views-the-timescale-wayTimescale editions https://docs.timescale.com/about/latest/timescaledb-editionsLoose indexscan https://wiki.postgresql.org/wiki/Loose_indexscan~~~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!~~~Postgres FM is produced by:Michael Christofides, founder of pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork