MySQL Collation Mismatch "Illegal Mix of Collations" in JOIN
The "Illegal mix of collations" error means you're comparing or joining two text values that use different collations (sorting/comparison rules) — MySQL...
Category
MySQL
Fixes for connection limits, query performance, and encoding issues in MySQL.
MySQL Connection Pool Exhausted, Too Many Active Connections
A connection pool reporting itself exhausted, even before hitting MySQL's own hard max_connections ceiling, means your application-level pool has run out of...
MySQL Datetime Implicit Conversion Causing Full Table Scan
An indexed datetime column being ignored, resulting in a full table scan, is very often caused by comparing that column against a value MySQL has to implicitly...
MySQL "Lock Wait Timeout Exceeded" Try Restarting Transaction
"Lock wait timeout exceeded" is different from a deadlock — it means your transaction waited the full configured timeout for a lock held by another...
MySQL "Out of Sort Memory" Error on Large Queries
MySQL's "out of sort memory" error means a query needing to sort a large result set (via ORDER BY, GROUP BY, or certain join operations) exceeded the memory...
MySQL Auto Increment Jumping Unexpectedly
Gaps appearing in an AUTO_INCREMENT sequence — IDs jumping from 105 straight to 150, for example — usually aren't a bug, but a normal consequence of how MySQL...
MySQL "Data Too Long for Column" Error Fix
The "data too long for column" error means the value you're trying to insert exceeds the maximum length defined for that column — but the actual character...
MySQL Dump File Too Large to Import, How to Split
A dump file too large to import comfortably usually isn't actually a hard limit being hit — it's more often a practical problem with timeouts, memory...
MySQL Foreign Key Constraint Fails on Delete
A foreign key constraint failure on delete means MySQL is protecting referential integrity — you're trying to delete a row that other rows still reference, and...