hard20 pts · first answer countsquery-tuningpostgresql

Prepared statement slows down later

A prepared query on a heavily skewed column is fast for the first five executions and then suddenly slow for some parameter values. What is the likely cause in PostgreSQL?

A.After several executions PostgreSQL may switch to a cached generic plan that ignores the actual parameter valueB.The statement cache is full and queries are now parsed twiceC.Autovacuum locks prepared statements after five runsD.pgBouncer rewrites the parameters to NULL

← Commits hang with sync replication Estimates wrong for city and zip code →