PCC bad query performance

Last post 02-17-2009 1:48 AM by m. gottschlich. 2 replies.
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  • 02-16-2009 9:55 AM

    PCC bad query performance

    Since I am using P10 (10.13.043) I have bad performance when I run several queries in PCC. If I run it in an ODBC based tool the performance is much better. Now I found out by using the Query plan viewer that in addition to my query a second query run which is similar to the original one but with a count. Unfortunatly this count query is needing so much time and for some of my queries the result could not be realy good (e.g. my query has TOP 1 so record count of the result is1 or 0, but the count statement gives all records).

    In on special case with a group by and Sum(Distinct(.. the count query crashes the engine.

    So my question is, if there is a possibility to supress this count query in PCC?

     

  • 02-16-2009 12:24 PM In reply to

    Re: PCC bad query performance

     The COUNT query is probably being used to generate the scroll bars in the Grid mode.  Try executing to "Text" mode.  Does performance increase. 

    At the same time, I never rely on PCC for performance testing.  I normally use ODBC Test because it give me the lowest application overhead.

  • 02-17-2009 1:48 AM In reply to

    Re: PCC bad query performance

    Mirtheil:
    The COUNT query is probably being used to generate the scroll bars in the Grid mode.  Try executing to "Text" mode.  Does performance increase.

    Same behavior when executing to grid!

    You are right that it is better to use the ODBC interface. But when I'am accessing clients systems the PCC is the only SQL interface to the database, and it is very critical when I run a SQL query which is working properly in my test, and on client site with using PCC it slows down (or in some circumstances crashes!!!!) the server engine! And the reason is a query which is automatically generated and which I can not influence.

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