121 articles · 35 databases · 63 topics
Practical tutorials, performance tuning and internals for SQL Server, PostgreSQL, MySQL, MongoDB, Redis and every engine in between — written by people who run them in production.
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SnowflakeIntermediateYou pay for warehouse run time, not query work. Find where the credits go, fix auto-suspend and warehouse sizes, and add resource monitors before the next invoice.
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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
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Tables, keys, joins and your first indexes. Build intuition that lasts.
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Query plans, transactions, replication and schema design trade-offs.
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SupabaseBeginnerNo error, just []. It's almost always Row Level Security. How RLS policies work, how to write and test them, and why the service role key is never the fix.
#security#troubleshooting
ClickHouseIntermediateTOO_MANY_PARTS means too many small inserts, not too much data. Batch your writes, turn on async inserts, and stop over-partitioning your MergeTree tables.
#configuration#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
Scan with a FilterExpression still reads and bills every item. Use GSIs, sparse indexes and composite sort keys instead, and know when to send queries elsewhere.
#data-modeling#indexing#nosql
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
