Answer
EXPLAIN shows how a query will execute, including index usage, join types, and cost estimates.
Quick Answer
EXPLAIN shows the query execution plan PostgreSQL will use without actually running the query. EXPLAIN ANALYZE runs the query and shows actual vs estimated row counts and execution times. Look for: sequential scans on large tables (may need an index), hash joins vs nested loops, rows estimates vs actual rows (big gap = stale statistics). Essential for performance debugging.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ