Topic
SQL ServerIntermediateA diagnostic catalogue of slow query causes in SQL Server: how to tell running from waiting, the plan or wait signature of each cause, and the fix.
#execution-plans#performance#troubleshooting
SQL ServerIntermediateA query-first method: find the expensive queries, read the plan for signs the missing index DMVs never report, build the index online safely, then verify and roll back.
#execution-plans#indexing#performance
SQL ServerIntermediateHow to measure SQL Server query performance with Query Store, DMVs and Extended Events, pick targets by total resource use, and check the settings that affect every query.
#configuration#db-administration#execution-plans
SQL ServerIntermediateQuery sys.dm_db_missing_index_details and its companion DMVs, read the numbers critically, find the queries behind each suggestion and merge them into the few indexes worth creating.
#db-administration#execution-plans#indexing
PostgreSQLBeginnerThe index exists, but the plan still shows a scan. Nine common reasons the optimizer can't (or shouldn't) use your index, and how to fix each one.
#execution-plans#indexing#performance
SQL ServerIntermediateSame proc, same code, suddenly 100× slower, and fast again when you run it in SSMS. Here's how parameter sniffing causes it, how to prove it and the fixes that actually hold.
#execution-plans#performance#troubleshooting
SQL ServerIntermediateExecution plans tell you exactly how SQL Server ran your query. Learn which operators matter, how to spot bad estimates and what the warnings really mean.
#execution-plans#performance#t-sql
PostgreSQLIntermediateLearn to read PostgreSQL query plans node by node — estimates vs. actuals, loops, buffers — and turn them into index and query fixes.
#execution-plans#indexing#performance
