Upgrade Query Load PostgreSQL · RDS Oss · aws/agent-toolkit-for-aws · Skills Docs

Upgrade Query Load PostgreSQL · RDS Oss · aws/agent-toolkit-for-aws · Skills Docs

SELECT queryid, query, calls, total_exec_time::numeric(12,2) AS total_time_ms,
  mean_exec_time::numeric(12,2) AS avg_time_ms,
  rows, shared_blks_hit, shared_blks_read
FROM pg_stat_statements
WHERE dbid = (SELECT oid FROM pg_database WHERE datname = current_database())
ORDER BY total_exec_time DESC LIMIT 5;

Pattern	Versions	Action
`Sort Method: external merge`	PG 15+	`work_mem` per-operation accounting changed. Tune `work_mem` and `hash_mem_multiplier`.
`HashAggregate` with `Batches > 1`	PG 15+	Memory accounting different. Adjust `work_mem`.
JIT on short queries	PG 14+	JIT overhead causes latency spikes. Adjust `jit_above_cost` thresholds.

Pattern	Versions	Action
Nested Loop without Memoize	PG 14+	PG 14 introduced Memoize. Usually beneficial. Set `enable_memoize=off` if regression.
Parallel scan threshold changes	PG 14-16	Plans may gain/lose parallelism. Compare on test instance.
Merge Join on large tables	PG 16+	Improved costing may change join strategy. Benchmark.