Blocking occurs after a alter table

Question

Dear experts,

There were few tables that were altered by the application team. And I noticed the stored procedure that queries these tables started to block other queries and finally the server hung and we had to reboot the server.

Could you please advise what may have caused this.

Is it the statistics when out of date or something?

Thanks,

Answer 1

Hi @mo boy ,

There were few tables that were altered by the application team

I think that's the key of causing the problem, what kind of action had been done?
For now I can just post this official link, I hope this can be helpful. : https://learn.microsoft.com/en-us/troubleshoot/sql/performance/understand-resolve-blocking
And you can use SQL Server profiler to see what kind of action causes the blocking.

The blocking can happen for many resaons like the blocked source has been in the RollBack state, a statement that runs for a long time because the client does not fetch the result set in time.....
You also need to check the specific action you put on your tables that causes the blocking, which is also the reason I recommend using the SQL Server profiler.

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