How to Resolve the \'Prepared statement needs to be re-prepared\' Error in MySQL?

Dealing with MySQL Prepared Statement Re-Preparation Errors

When migrating your PHP site to a hosting server, you may encounter the perplexing "Prepared statement needs to be re-prepared" error. This often occurs after implementing MySQL Stored Procedures in your code.

The root of this issue may lie in a known MySQL bug (#42041). To address it, you need to increase the value of the table_definition_cache parameter.

Statement Caching in MySQL

To optimize performance, MySQL caches certain information about tables, including their definitions. The table_definition_cache parameter controls the size of this cache. When the cache is too small, it may lead to the "Prepared statement needs to be re-prepared" error, especially when tables are frequently altered.

Increasing the table_definition_cache Value

To fix the error, you need to increase the value of table_definition_cache in your MySQL configuration file (usually named my.cnf). Find the [mysqld] section and add the following line:

table_definition_cache=1000

The optimal value for table_definition_cache depends on your specific usage patterns. A higher value allows MySQL to cache more table definitions, reducing the likelihood of re-preparing statements.

After making this change, restart your MySQL server for the settings to take effect. This should eliminate the "Prepared statement needs to be re-prepared" error on your hosting server.

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