EXPLAIN: make it make sense
summary
Shows how EXPLAIN and ANALYZE with PostgreSQL reveal actual vs estimated rows, uses Python/Django and RDS, and proves random_page_cost=4 keeps the planner favoring scans on cloud. Demonstrates concrete fixes: create INDEX ON upper(name) for case-insensitive lookups, install pg_trgm extension for ILIKE partial matches, run ANALYZE after adding indexes, and rewrite OR conditions as UNIONs to speed a seven-table live search — the UNION version runs 4–5× faster and the corrected JSON expression index finally lets the query use an index.
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chapters (7)
- 0:00Introduction to EXPLAIN
- 1:50Theory behind database indexes
- 8:35Practical query tuning with Django
- 12:56Index limitations and fixes
- 18:43Trigram indexes for partial text search
- 23:40Combining indexes in live search
- 27:13Q&A session
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