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Description

Error 1615 indicates that a previously prepared SQL statement is no longer valid and must be prepared again before it can be executed. This typically occurs when the underlying database schema changes, the server restarts, or certain session-specific conditions invalidate the statement's execution plan.

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Error Message

Prepared statement needs to be re-prepared

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Known Causes

3 known causes

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Database Schema Changes

Altering tables (e.g., adding/dropping columns, changing data types) used by a prepared statement can invalidate its cached execution plan.

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MariaDB Server Restart

Prepared statements are often stored in memory or are session-specific. A server restart clears this state, requiring all active prepared statements to be re-prepared.

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Session-Specific Invalidation

Certain session-level commands or changes in transaction state can implicitly invalidate prepared statements within the current connection.

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Solutions

3 solutions available

1. Re-execute the Prepared Statement easy

The most straightforward solution is to simply re-execute the prepared statement.

1

When your application receives the MariaDB Error 1615, it should catch this specific error code and then re-prepare and re-execute the SQL statement that caused the error. This is the standard way to handle prepared statement invalidation.

Example in a hypothetical application framework:

try {
  // Execute prepared statement
  $result = $db->executePrepared('SELECT * FROM users WHERE id = ?', [123]);
} catch (MariaDbException $e) {
  if ($e->getCode() === 1615) {
    // Re-prepare and re-execute
    $db->prepare('SELECT * FROM users WHERE id = ?');
    $result = $db->executePrepared('SELECT * FROM users WHERE id = ?', [123]);
  } else {
    // Handle other errors
    throw $e;
  }
}

2. Check for Schema Changes medium

Investigate if any schema modifications occurred that might invalidate prepared statements.

1

Error 1615 often occurs when the schema of the table(s) involved in the prepared statement changes after the statement has been prepared. This could be due to `ALTER TABLE`, `DROP TABLE`, `TRUNCATE TABLE`, or other DDL statements.

2

Review MariaDB server logs for any DDL statements that were executed around the time the error started occurring. Look for statements like `ALTER TABLE`, `DROP TABLE`, `CREATE TABLE`, etc.

Example log snippet (may vary based on log configuration):
2023-10-27 10:30:05 12345 [Note] /usr/sbin/mysqld: ALTER TABLE orders ADD COLUMN quantity INT;

3

If schema changes are detected, ensure your application logic gracefully handles these changes. This might involve re-preparing statements after known schema modifications or implementing a more robust error handling strategy as described in Solution 1.

3. Review Connection Pooling and Statement Cache advanced

Examine how your application manages database connections and prepared statement caches.

1

Some database connection pools or ORMs maintain a cache of prepared statements. If the underlying schema changes, the cached prepared statement might become stale and lead to Error 1615 when reused. Ensure your connection pool or ORM has mechanisms to invalidate or refresh cached statements when schema changes are detected.

2

Consult the documentation for your specific connection pooling library or ORM (e.g., HikariCP, C3P0, SQLAlchemy, Doctrine) to understand its prepared statement caching behavior and how to manage it.

3

Consider disabling or limiting the prepared statement cache if schema changes are frequent and difficult to manage, or if the overhead of re-preparing statements is acceptable.

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Related Errors

5 related errors

MariaDB Error 1615: Prepared Statement Invalidation