To get the row count for your selection, create a partial index: CREATE INDEX t1_t2_id_7_idx ON t1((1)) WHERE t2_id = 7 Ī row for the partial index incl. There are basic statistics in pg_class and much more in pg_statistic (or the human-readable view pg_stats based on it). For read-only tables, statistics in the system catalog are just as good. A fresh count just minimizes the time window.
Any count is an estimate after all and may be outdated the moment you see it. MySQL is developed with a focus on speed. > Bitmap Index Scan on index_t2 (cost=44.41 rows=34691712 width=0) (actual time=59948.598.59948.598 rows=31383566 loops=1) PostgreSQL vs MySQL Main Focus, PostgreSQL is developed with a focus on features and standards. Server: AWS RDS (db.r3.xlarge) vCPU:4 Memory:30Gb Request (returns ~30M): SELECT COUNT(*) FROM t1 WHERE t2_id = 7 PostgreSQL vs MySQL: Explore Their 12 Critical Differences Salman Ravoof, Data is essentially just a collection of different facts and observations.
MySQL provides performance, speed, and ease of use as primary features. Choosing between the two depends on the specific requirements for a project and a database administrator's experience. MySQL table definition: CREATE TABLE t1 ( MySQL vs PostgreSQL: Which One Should You Use Both MySQL and PostgreSQL are popular open-source database management systems with unique features. And I don't understand is it a normal behaviour of PostgeSQL or I do something wrong. I benchmark DBs to find out the best for my project and I found that count(*) is extremely slow in PostgeSQL. Performance difference between MySQL and PostgreSQL for the same schema/queries - Database Administrators Stack Exchange Performance difference between MySQL and PostgreSQL for the same schema/queries closed Ask Question Asked 10 years ago Modified 9 years, 8 months ago Viewed 47k times 20 Closed.
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