Troubleshooting MySQL Error 2014 – (CR_COMMANDS_OUT_OF_SYNC)

by

When you encounter MySQL Error 2014, it typically indicates that you’re trying to execute a new command without having properly handled the results from a previous command. This error can be perplexing, but understanding why it occurs and how to fix it is crucial for maintaining smooth operations in your MySQL databases. Let’s dive into the potential causes and solutions for this error.

Understanding the Error

Error 2014 – (CR_COMMANDS_OUT_OF_SYNC) means that the client and server are out of sync with each other. In MySQL, you must fetch or consume all results from the previous command before issuing a new one. If the client disregards this rule, MySQL raises this error to prevent unexpected behavior.

Diagnosing the Error

To diagnose this error, check for the following common scenarios in your MySQL operations:

  1. Unconsumed Results: If you execute a command that returns a result set, you must fetch all the rows from the result before issuing another command.
  2. Multiple Statements: If you’re using a MySQL client library that supports multiple statements, ensure that you are processing the results of each statement before executing new ones.
  3. Stored Procedures: When calling stored procedures that return multiple result sets, you must retrieve all result sets before executing another command.

Fixing the Error

Here are some examples and sample code to help you resolve MySQL Error 2014:

Example 1: Fetching All Results

If you’re executing a SELECT query, make sure to fetch all rows:

$query = "SELECT * FROM my_table";
if ($result = $mysqli->query($query)) {
    while ($row = $result->fetch_assoc()) {
        // Process each row
    }
    $result->free(); // Free the result set
}

Example 2: Handling Multiple Statements

When using multiple statements, process each result set before moving on:

$mysqli->multi_query("CALL sp_returns_multiple_results()");
do {
    if ($result = $mysqli->store_result()) {
        while ($row = $result->fetch_assoc()) {
            // Process each row
        }
        $result->free();
    }
} while ($mysqli->next_result());

Example 3: Dealing with Stored Procedures

For stored procedures that return multiple result sets, handle them properly:

$mysqli->multi_query("CALL sp_returns_multiple_results()");
do {
    if ($result = $mysqli->store_result()) {
        while ($row = $result->fetch_assoc()) {
            // Process each row
        }
        $result->free();
    }
    // This is crucial to avoid Error 2014
    if (!$mysqli->more_results()) {
        break;
    }
} while ($mysqli->next_result());

By following the correct sequence of operations and ensuring that all results are consumed before issuing a new command, you can prevent Error 2014 from occurring. It’s important to review your code for any instances where results may not be fully retrieved or where commands may be inadvertently executed out of order. Proper error handling and result set management are key to maintaining synchronization between your client and MySQL server.

If you continue to experience this error after applying these fixes, it may be helpful to isolate the problematic part of your code and test it separately or seek further assistance from the MySQL community or documentation. Remember, keeping your commands and results in sync is essential for the stability and reliability of your MySQL interactions.

Leave a Comment