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Description

This error indicates that a previously prepared SQL statement is no longer valid on the MySQL server and must be re-prepared by the client application. It typically occurs when server-side conditions or underlying database objects change, invalidating the statement's execution plan.

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Error Message

Prepared statement needs to be re-prepared

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Known Causes

4 known causes

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Schema Modifications

Changes to the database schema, such as altering a table, dropping an index, or modifying a view, can invalidate prepared statements that depend on those objects.

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Server Restart or Disconnect

If the MySQL server restarts or the client's connection is lost and re-established, all server-side prepared statements are discarded, requiring re-preparation.

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Statement Inactivity Timeout

Some MySQL configurations or connection pool settings might automatically close inactive prepared statements after a certain period, leading to their invalidation.

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Cursor Invalidation

For prepared statements involving cursors, certain operations or server-side events can cause the associated cursor to become invalid, requiring the statement to be re-prepared.

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Solutions

3 solutions available

1. Re-execute the Prepared Statement easy

The most direct solution is to simply re-execute the prepared statement that caused the error.

1

Identify the application code that is executing the prepared statement.

2

Ensure that the application logic includes a retry mechanism or simply re-executes the statement when this error (1615) is encountered.

Example in Python using `mysql.connector`:

try:
    cursor.execute(prepared_statement, params)
    results = cursor.fetchall()
except mysql.connector.errors.InternalError as err:
    if err.errno == 1615:
        print("Prepared statement invalidated, re-executing...")
        cursor.execute(prepared_statement, params) # Re-execute
        results = cursor.fetchall()
    else:
        raise

2. Handle Prepared Statement Invalidation in Application Logic medium

Implement robust error handling in your application to catch and re-prepare statements when necessary.

1

Review your application's data access layer or ORM configuration.

2

Implement a mechanism to detect `1615` errors. Upon detection, close the current statement and re-prepare it before re-executing the query.

Example in Java using JDBC:

java
try {
    PreparedStatement pstmt = connection.prepareStatement("SELECT * FROM users WHERE id = ?");
    pstmt.setInt(1, userId);
    ResultSet rs = pstmt.executeQuery();
    // Process results
    rs.close();
    pstmt.close();
} catch (SQLException e) {
    if (e.getErrorCode() == 1615) {
        System.err.println("Prepared statement invalidated. Re-preparing and re-executing.");
        // Re-prepare and re-execute logic here
        // You might need to re-establish the connection or re-prepare the statement
        // depending on the context and the specific JDBC driver.
        // For simplicity, a basic re-execution attempt:
        try {
            PreparedStatement pstmt = connection.prepareStatement("SELECT * FROM users WHERE id = ?");
            pstmt.setInt(1, userId);
            ResultSet rs = pstmt.executeQuery();
            // Process results
            rs.close();
            pstmt.close();
        } catch (SQLException retryException) {
            // Handle persistent failure
            retryException.printStackTrace();
        }
    } else {
        e.printStackTrace();
    }
}

3. Server-Side Prepared Statement Cache Management advanced

While MySQL's server-side cache is generally efficient, understanding its behavior can help diagnose persistent issues.

1

Understand that MySQL caches prepared statements on the server. This error indicates that the cached statement has become invalid.

2

If this error is frequent and not clearly tied to schema changes, investigate potential causes like server restarts, `KILL`ing of connections holding statements, or very aggressive connection pooling on the client side that might be closing and reopening connections frequently.

3

Consider adjusting the `max_prepared_statements_count` server variable if you suspect you are hitting a limit, though this is less common for error 1615 itself and more for general prepared statement exhaustion.

SHOW VARIABLES LIKE 'max_prepared_statements_count';

4

Ensure your application's connection pooling is configured to handle prepared statement invalidations gracefully, perhaps by re-preparing statements when connections are re-established.

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Related Errors

5 related errors

MySQL Error 1615: Prepared Statement Invalidation