Parallel Execution or Multi Thread Execution of Stored Procedure.

Question

Hi, I have a Stored Procedure, that compares data from multiple tables and adds into my main table.

This Stored Procedure will run on a large amount of data to add data in the main table. What I need help with is that I want to run multiple instances of the same stored procedure which execute parallelly at the same time on different sets of data and insert data into the main table without causing any kind of Deadlock.

Any help would be appreciated to pe able to achieve this kind of Multi-Thread Execution approach.

Thank You in Advance.

Answer 1

Ayush Singh
Thank you for the question and for using Microsoft Q&A platform.
To run multiple instances of a stored procedure in parallel on different sets of data without causing deadlocks, there are several approaches you can consider. Here’s a breakdown of the steps and best practices:

1. Partition Your Data

Divide your data into smaller, non-overlapping partitions. Each instance of the stored procedure will work on a different partition. This minimizes the risk of deadlocks since each instance will be working on a different subset of data.

2. Use SQL Server Agent Jobs

Create multiple SQL Server Agent jobs, each executing the stored procedure with a different partition of data. Schedule these jobs to run simultaneously.

3. Transaction Management

Ensure that each stored procedure instance uses transactions properly. Use the WITH (NOLOCK) hint for read operations if appropriate but be cautious as it can lead to dirty reads.

4. Optimistic Concurrency Control

Consider using optimistic concurrency control techniques. For example, use a timestamp or version number to ensure that updates do not conflict.

5. Lock Hints

Use lock hints like ROWLOCK, UPDLOCK, or TABLOCK to control the locking behavior of your transactions. This can help reduce the likelihood of deadlocks.

6. Error Handling and Retry Logic

Implement robust error handling and retry logic. If a deadlock occurs, the transaction should be retried after a short delay.

7. Parameterize the Stored Procedure

Modify your stored procedure to accept parameters that define the data subset it will work on. For example, you could add parameters like @StartID and @EndID for range-based partitioning. This will allow each instance to focus on its assigned subset without interfering with others.

Example:

CREATE PROCEDURE MyStoredProcedure
    @StartID INT,
    @EndID INT
AS
BEGIN
   
    INSERT INTO MainTable (Column1, Column2, ...)
    SELECT Column1, Column2, ...
    FROM SourceTable
    WHERE ID BETWEEN @StartID AND @EndID;
END;

For more information you can refer to these links:
https://learn.microsoft.com/en-us/sql/ssms/agent/create-a-job?view=sql-server-ver16
https://learn.microsoft.com/en-us/sql/ssms/agent/sql-server-agent?view=sql-server-ver16
https://learn.microsoft.com/en-us/sql/t-sql/queries/hints-transact-sql-table?view=sql-server-ver16
https://www.mssqltips.com/sqlservertip/6290/sql-server-update-lock-and-updlock-table-hints/
https://learn.microsoft.com/en-gb/sql/relational-databases/partitions/partitioned-tables-and-indexes?view=sql-server-ver16
https://learn.microsoft.com/en-gb/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-ver16
https://learn.microsoft.com/en-gb/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-ver16
https://learn.microsoft.com/en-us/azure/azure-sql/database/analyze-prevent-deadlocks?view=azuresql&tabs=ring-buffer

Hope this helps. Do let us know if you have any further queries.

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