What's wrong with this SQL COUNT?
What's wrong with this SQL COUNT in an API. The SQL code uses COUNT(*) on a huge table for every request, causing slow queries and CPU spikes. In SQL services this creates latency incidents.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlcount #sqlslowquery #sqlapi #sqllatency
What's wrong with this SQL dedupe?
What's wrong with this SQL dedupe in a reporting job. The SQL code uses DISTINCT on the wrong columns, collapsing distinct events into one. In SQL analytics this undercounts revenue and traffic.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqldistinctbug #sqldedupe #sqldataloss #sql...
What's wrong with this SQL order by?
What's wrong with this SQL order by in a search endpoint. The SQL code interpolates a user supplied sort field, enabling injection. In SQL backends this exposes data and crashes queries.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlinjection #sqlorderby #sqlquery #sqlsecurity
Why does this SQL index not get used?
Why does this SQL index not get used in production. The SQL query wraps the indexed column in a function, preventing index use. In SQL services this turns fast queries into table scans.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlindex #sqlfunctiononcolumn #sqlqueryplan #sqlo...
Why does this SQL delete skip rows?
Why does this SQL delete skip rows in a cleanup job. The SQL code deletes with LIMIT and OFFSET, so rows shift and some never get deleted. In SQL maintenance this leaves stale data forever.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqldelete #sqloffsetbug #sqlcleanup #sqlmainten...
What's wrong with this SQL cache key?
What's wrong with this SQL cache key in production. The SQL layer caches results without a locale key, so users see cached content in the wrong language. In SQL backed APIs this causes localization incidents.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlcachekey #sqli18nbug #s...
What's wrong with this SQL cache miss?
What's wrong with this SQL cache miss in a quota service. The SQL layer treats zero as false and refetches on every call. In SQL backed APIs this causes unnecessary load and latency.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlcachebug #sqlfalsey #sqlquota #sqldatabaseload #...
Why does this SQL lock table block readers?
Why does this SQL lock table block readers in production. The SQL code runs a long update in a transaction, holding locks and blocking reads. In SQL services this causes latency spikes and timeouts.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqllock #sqltransaction #sqlla...
Why does this SQL cache leak across tenants?
Why does this SQL cache leak across tenants in production. The SQL layer caches results without a tenant key, so one tenant sees another tenant's data. In SQL multi tenant apps this is a privacy incident.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlcachekey #sqlmultite...
What's wrong with this SQL hmac check?
What's wrong with this SQL HMAC check in a webhook table. The SQL code compares signatures with a non constant time check in application logic. In SQL backed services this allows timing attacks.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlhmac #sqltimingattack #sqlwebhook #s...
What's wrong with this SQL file import?
What's wrong with this SQL file import job. The SQL code loads a CSV with the wrong delimiter and silently shifts columns. In SQL pipelines this corrupts data without errors.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlimport #sqlcsv #sqldatacorruption #sqlpipeline #sqletl
Why does this SQL join explode rows?
Why does this SQL join explode rows in production. The SQL code joins two tables without a proper predicate, causing a cartesian explosion. In SQL services this creates massive duplicates and outages.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqljoinbug #sqlcartesian #sqloutage...
What's wrong with this SQL pagination?
What's wrong with this SQL pagination in a busy table. The SQL code uses OFFSET while new rows are inserted, so items shift and get skipped. In SQL APIs this causes missing and duplicated results.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity #sqlengineering #sqlpaginationbug #sqloffsetpagination...
Why does this SQL retry charge customers twice?
Why does this SQL retry logic charge customers twice in production. The SQL code inserts a charge record on retry without an idempotency key, so the gateway processes duplicates. In SQL billing systems this creates double charges and refunds.
#whatswrongwiththissqlquery #sqlbug #sqlproductionbug #sqldebugging #sqldatabase #sqlcodereview #sqlperformance #sqlreliability #sqlanalytics #sqldataintegrity...
Index On NULL Column Does NOTHING?!
Your performance just DIED! Created an index but queries with NULL are still slow? Indexes IGNORE NULL values! Full table scan on millions of rows! Your index is USELESS! Watch the disaster!
#sql #sqlperformance #index #null #fulltablescan #slowquery #sqlfails #productionbug #sqlshorts #databasedisaster #sqlwtf #indextrap
450× Faster Joins with Index Condition Pushdown
#HackerNews #450xFasterJoins #IndexConditionPushdown #DataOptimization #SQLPerformance #ReadySet
🚨 Dataverse Plug-in Timing Out?
Slow queries and blocking operations can crash plug-ins! Learn how to prevent SQL timeout errors and boost plug-in performance 🚀👇
#Dataverse #PowerPlatform #SQLPerformance #PlugInOptimization #Dynamics365
http://mytrial365.com/2025/05/01/blog-4-resolving-sql-timeout-errors-in-dataverse-plug-ins/
Measure Db2 Elapsed Time: Efficiently Track Database Query Execution Duration
Master Db2 Elapsed Time for database query optimization! Learn methods from simple timestamp comparisons to advanced DB2 tools. Improve your #Db2Optimization #DatabasePerformance #SQLPerformance #QueryOptimization #DB2Tips #DatabaseTuning
https://tech-champion.com/database/db2luw/measure-db2-elapsed-time-efficiently-track-database-query-execution-duration/
DB2 Subquery Optimization: Improving View Performance
Master DB2 Subquery Optimization techniques for efficient database performance. Learn to rewrite subqueries using joins, leverage indexes, and utilize DB2's query optimization features. #DB2Optimization #SubqueryOptimization #DatabasePerformance #SQLPerformance #DB2LUW #QueryOptimization
https://tech-champion.com/database/db2luw/db2-subquery-optimization-improving-view-performance/
