Re: Serious Flaws in 7.23's Optimizer - Not using indexes
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Paul Mosser schrieb:
> Try setting OPTCOMPIND (in the onconfig file) to 0, instead of the
> default 2.
>
> --
> ==============================
> pmosser@minisoftinc.com
> Paul A. Mosser, Developer/DBA
> MiniSoft, Inc. Phoenix, AZ U.S.A.
>
> } -----Original Message-----
> } From: alan.cowan@autodesk.com [SMTP:alan.cowan@autodesk.com]
> } Sent: Wednesday, August 06, 1997 9:38 AM
> } To: informix-list@rmy.emory.edu; Alastair Kimbell
> } Subject: Serious Flaws in 7.23's Optimizer - Not using indexes
> }
> } In a nutshell:
> } The Optimizer does not usee indexes even if EVERY join is an
>
> } indexed
> } field.
> } Lots of problems in other examples including every time I
> use
> } EXISTS it
> } does a SEQUENTIAL search where an index is available.
> } Informix 5 did not have these problems.
> }
> } [snip]
> }
> } Wish I were back with v5
> }
> } Alan Cowan
It seems there are some things which upset the optimizer. If playing
with OPTCOMPIND does not help, try the following
UPDATE STATISTICS MEDIUM FOR table
UPDATE STATISTICS HIGH FOR table (keyfield1)
UPDATE STATISTICS HIGH FOR table (keyfield2)
.....
Good luck
Helmut
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Paul Mosser schrieb:
<BLOCKQUOTE TYPE=CITE>Try setting OPTCOMPIND (in the onconfig file) to
0, instead of the
<BR>default 2.
<P>--
<BR>==============================
<BR>pmosser@minisoftinc.com
<BR>Paul A. Mosser, Developer/DBA
<BR>MiniSoft, Inc. Phoenix, AZ U.S.A.
<P>} -----Original Message-----
<BR>} From: alan.cowan@autodesk.com [SMTP:alan.cowan@autodesk.com]
<BR>} Sent: Wednesday, August 06, 1997 9:38 AM
<BR>} To: informix-list@rmy.emory.edu; Alastair Kimbell
<BR>} Subject: Serious Flaws in 7.23's Optimizer
- Not using indexes
<BR>}
<BR>} In a nutshell:
<BR>} The Optimizer does
not usee indexes even if EVERY join is an
<BR>} indexed
<BR>} field.
<BR>} Lots of problems
in other examples including every time I use
<BR>} EXISTS it
<BR>} does a SEQUENTIAL
search where an index is available.
<BR>} Informix 5 did not
have these problems.
<BR>}
<BR>} [snip]
<BR>}
<BR>} Wish I were back with v5
<BR>}
<BR>} Alan Cowan</BLOCKQUOTE>
It seems there are some things which upset the optimizer. If playing with
OPTCOMPIND does not help, try the following
<BR> UPDATE STATISTICS MEDIUM FOR table
<BR> UPDATE STATISTICS HIGH FOR table (keyfield1)
<BR> UPDATE STATISTICS HIGH FOR table (keyfield2)
<P> .....
<P>Good luck
<BR>Helmut
<BR> </HTML>
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