long waits on a query

  • Hi Experts,

    I have multiple questions in one thread. please excuse me. All related to one particular query.

    We are seeing some pagelatch_up and pagelatch_sh waittypes for one of the query.

    What are these waittypes means? Will they go hand in hand ? when do we see both together.

    How can we minimize or eliminate these waittypes ?

    Also, in sp_whoisactive it is shown on PFS page. my other doubt is that, is it PFS page contention is on tempdb or cmx_ors database?

    Is there a way to log that tempdb allocation contention or specific database allocation contention happened in the ERRORLOG . Is there a trace flag to log such information in the errorlog? The reason why I am asking this is, we have a cx asking that we are seeing high waits for a query. if this info is logged somewhere, we can prove at that particular time frame, there was some contention happening. At this point, we are capturing sp_whoisactive output into a table every 15 mins.

    Below is the screenshots of sp_whoisactive and some DPA information.

     

    Thanks,

    Sam

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  • Thanks for posting your issue and hopefully someone will answer soon.

    This is an automated bump to increase visibility of your question.

  • Common latch information

    https://documentation.red-gate.com/sm9/overview-pages/using-performance-diagnostics/list-of-common-wait-types/

    May be related since you mentioned tempdb.  This helps with tempdb contention.

    https://logicalread.com/sql-server-tempdb-best-practices-multiple-files-w01/#.XXgAuihKiUk

     

  • Take a look at this library of wait types from SQLSKills.

    Also, do you have any moniotring tools in place, like Database Performance Analyzer?

    https://www.sqlskills.com/help/waits/

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