When an index does more harm than good: cleaning PostgreSQL waste
PostgreSQL: how to find and drop unused indexes with pg_stat_user_indexes. Real case: a table with 15 indexes, 8 of them never used.
Query-Tuning
5 tagged articles
PostgreSQL
Oracle
AWR, ASH and the 10 minutes that saved a go-live
Oracle 19c performance tuning with AWR and ASH: finding a hidden full table scan in a stored procedure in 10 minutes, the eve of a go-live.
PostgreSQL
When a LIKE '%value%' Slows Everything Down: A Real PostgreSQL Optimization Case
PostgreSQL optimization: LIKE '%value%' causes full scan. Using pg_trgm and GIN index to turn a wildcard search into a fast lookup. Real case.
Oracle
Oracle Partitioning: when 2 billion rows no longer fit in a query
Oracle Partitioning on a 2-billion-row table: range, interval, partition pruning, local indexes. From hours to seconds on reporting queries.
PostgreSQL
EXPLAIN ANALYZE is not enough: how to actually read a PostgreSQL execution plan
PostgreSQL EXPLAIN ANALYZE: reading an execution plan, spotting costly nested loops and stale statistics. Real case on 2-million-row table.