SQL connection error X++ exception

This topic describes the SQL connection error exception types in X++.

TransientSqlConnectionError X++ exception

During an X++ SQL query execution, when a transient SQL connection error occurs on the server side, a TransientSqlConnectionError X++ exception will occur. Depending on the application requirements, the application should catch and handle the exception.

This exception usually occurs during a large transaction or when the database is under a lot of processing pressure.

The TransientSqlConnectionError exception is not catchable within the transaction. The X++ transaction that encounters this exception is canceled (calling ttsAbort) before the exception occurs. This means that you need to use the catch block to identify the transient SQL connection error instead of a generic X++ error exception, and then retry the outermost transaction or retry application code logic in a new session. This exception allows the application to be designed for transient server failures.

If an application transaction takes a long time to process, you can use multiple incremental delays to catch the TransientSqlConnectionError exception. Retrying your application code in a new session is most likely to succeed after you have caught the exception.

Example

public static void LargeTransactionWrapper()
{
    try
    {
        LargeTransaction();
    }
    catch (Exception::TransientSqlConnectionError)
    {
        info("Caught transient SQL connection error, ttslevel=" + int2Str(appl.ttsLevel()));
        // At this point, transaction is canceled
        // Code that indicates retry is possible
    }
    finally
    {
        // Do clean up
    }
}