Optimizer statistics summarize data characteristics so PostgreSQL can estimate query costs and choose an execution plan. Important inputs include cardinality, distinct-value counts, and histograms. section 6.7
Treating statistics collection as optional is a performance mistake. Disabling autovacuum or autoanalyze, or weakening autovacuum for a write-intensive workload, can leave statistics inaccurate while bloat accumulates. section 6.7 section 6.13
Use these operational checks when query performance deteriorates:
- Inspect EXPLAIN output to identify whether inaccurate estimates contribute to a poor plan. section 6.13
- Keep autovacuum effective rather than disabling it to save resources; write-heavy systems need maintenance capacity. section 6.7
- If maintenance competes with application work, scale the system, reduce costly queries, or reconsider the database architecture instead of suppressing statistics collection. section 6.7
A tempting production shortcut
A write-intensive PostgreSQL deployment turns down autovacuum to reduce resource consumption. Over time, bloat grows and optimizer statistics become inaccurate, increasing the chance of poor plans and application delays. Checking EXPLAIN provides a direct way to investigate the slow query; restoring effective maintenance addresses the underlying operational mistake. section 6.7 section 6.13
