Dead lock under high loads

Discussion of open issues, suggestions and bugs regarding SDAC (SQL Server Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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Posts: 26
Joined: Wed 04 Oct 2006 01:41

Dead lock under high loads

Post by oodesigns » Tue 24 Jul 2007 15:17


We are using the SDAC ver 4 with 80 connections to a database. With high loads that are 50 - 80 % cpu the database request just stop.

We cannot give you the code as it is built into a multithread server.

Any thoughts?

Posts: 2098
Joined: Tue 14 Feb 2006 10:14

Post by Antaeus » Wed 25 Jul 2007 09:45

Probably you have encountered the problem with SQL Server locking. You should not use FetchAll=False mode in your datasets, as underfetched datasets may lead to the locking issues.
Another possible reason is incorrect working with SDAC in multiple threads. You should use one TMSConnection object in each thread, and enable pooling for each TMSConnection. Pooling will help you to increase performance of your application.

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