SQL Server Performance

Unwanted Connection Pools

Discussion in 'SQL Server 2005 Performance Tuning for DBAs' started by brookerrj, Mar 14, 2007.

  1. brookerrj New Member

    We are running some very stringent performance tests on a .net web application with a network load balanced three web servers farm connecting to an SQL cluster.
    We are using SQL server for session state as well as the application data.
    We are using Application Centre Test (ACT) to drive the application from 5 client PCs simulating 300 concurrent users.
    During a 1 hour test we are required to return 95% of the application pages within 5 seconds.
    Most of the time we achieve the performance requirements but in about 1 in 10 runs we see a performance degradation so that we only achieve a figure of 84%.

    Our application uses four connection pools that are defined in the web.config file for each web server.
    Normally when we monitor connections using the performance monitor we see that each web server is using the 4 connections pools.
    When we have a bad run we have noticed that one or more of the web servers has more than 4 connection pools, sometimes as many as 20.
    There is also an increase in the number of pooled connections on those servers.
    The connection pools do not go away until the server is rebooted.

    We have noticed that if we restart IIS on a web server and re-run our application a new set of 4 connection pools are created and we will then have 8.
    Why would this be?
    Is rebooting the only way to make the connection pools go away?
    We don#%92t understand why the extra pools should make a difference anyway but they do seem to.
    The pooled connections in the unused pools should not be being used.

    Has anybody got any ideas or suggestions for other things we might look at?

    Thanks
  2. Adriaan New Member

    I don't know enough about IIS, but it seems like IIS can have its own connection pools. I do know that SQL Server can have its own connection pool. So do you know which connection pools you are actually monitoring?
  3. brookerrj New Member

    quote:Originally posted by Adriaan

    I don't know enough about IIS, but it seems like IIS can have its own connection pools. I do know that SQL Server can have its own connection pool. So do you know which connection pools you are actually monitoring?

    We are monitoring the PerfMon counters on the web servers.
    The counters are called:

    SqlClient: Current # connection pools
    SqlClient: Current # pooled connections
  4. brookerrj New Member

    We are using SQL server 2000. I have realised the I posted in the wrong Topic.
    Will repost under SQL Server 2000.
  5. Adriaan New Member

    Okay, so this is on the IIS side of things.

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