Error
Error Code:
1104
MySQL Error 1104: Excessive Rows Examined
Description
This error indicates that a SELECT query is attempting to process more rows than allowed by the MAX_JOIN_SIZE system variable. It typically occurs when a query lacks proper WHERE clauses or involves large joins without sufficient filtering, potentially leading to performance issues or server overload.
Error Message
The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay
Known Causes
4 known causesMissing or Inefficient WHERE Clause
Queries without a WHERE clause or with very broad conditions can lead to scanning an entire table or large portions of it, exceeding MAX_JOIN_SIZE.
Large Joins Without Filters
Joining multiple large tables without adequate filtering conditions in the ON or WHERE clauses can result in a massive intermediate result set.
Insufficient MAX_JOIN_SIZE Setting
The current MAX_JOIN_SIZE system variable might be set too low for legitimate, large analytical queries, preventing them from completing.
Unindexed Columns in Joins/WHERE
When JOIN or WHERE conditions use unindexed columns, MySQL must perform full table scans, drastically increasing the number of rows examined.
Solutions
Coming SoonDetailed step-by-step solutions for this error are being prepared. In the meantime, try these general troubleshooting tips:
General Troubleshooting Tips
- Check the error message carefully for specific details
- Review recent changes that might have caused the error
- Search for the exact error code in the official documentation
- Check log files for additional context
- Try restarting the application or service