SQL freezes or fails randomly, how to timeout or try/catch?

Hi,

I have a function that only has an sql pull in it. Sometimes it works, sometimes it doesnt. In another function that calles the sql pulls, if it is run together, it fails. If it stops right before and I run the function by putting it in the workspace, it works. Sometimes it crashes matlab. When it fails, it usually holds for a long time. Normally it should only take about 2 seconds when it does work. Is there a timeout function I can use to break matlab away from it when it freezes on the sql pull? How could I used a try/catch statement to catch it and make it try it again if it doesnt work?

Answer 1

[Piyush Kumar]

Hi,

To handle SQL freezes or failures in MATLAB, you can use a combination of try/catch blocks and setting a timeout for your database connection.

1. Setting a Timeout: You can specify "LoginTimeout" while establishing connection to the database. It specifies the number of seconds that the driver waits while trying to connect to a database before throwing an error. Refer to the "Name-Value Arguments" section of this link for more details.
2. Using try/catch: You can wrap your SQL pull in a try/catch block to handle any errors and retry the operation if it fails.

    maxRetries = n; % Maximum number of retries
    retryCount = 0;
    success = false;
    % Define sql query 
    while ~success && retryCount < maxRetries
        try
            % Execute SQL query
            curs = exec(conn, sqlquery);
            success = true; % If query is successful, set success to true
        catch ME
            % If an error occurs, increment retry count and display error message
            retryCount = retryCount + 1;
            disp(['Attempt ' num2str(retryCount) ' failed: ' ME.message]);
            pause(2); % Pause for 2 seconds before retrying
        end
    end
    
    if ~success
        error('Failed to execute SQL query after multiple attempts.');
    end