Re: [PERFORM] bad join performance

2003-08-18 Thread pginfo
Ok,
thanks for the help
and best regards.
ivan.

Tom Lane wrote:

> pginfo <[EMAIL PROTECTED]> writes:
> > sorry for my bad.
> > My production server is 7.3.7, but the development is 7.3.1 and I ran the
> > tests on 7.3.1.
>
> > It is courios that on 7.3.1 the query is not constantly bad.
> > From time to time it is running well.
>
> Yeah, the mergejoin estimation bug doesn't bite in every case (if it
> did, we'd have found it before release ;-)).  Please update to 7.3.4.
>
> regards, tom lane




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Re: [PERFORM] bad join performance

2003-08-18 Thread Tom Lane
pginfo <[EMAIL PROTECTED]> writes:
> sorry for my bad.
> My production server is 7.3.7, but the development is 7.3.1 and I ran the
> tests on 7.3.1.

> It is courios that on 7.3.1 the query is not constantly bad.
> From time to time it is running well.

Yeah, the mergejoin estimation bug doesn't bite in every case (if it
did, we'd have found it before release ;-)).  Please update to 7.3.4.

regards, tom lane

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Re: [PERFORM] bad join performance

2003-08-18 Thread pginfo
Hi tom,
sorry for my bad.
My production server is 7.3.7, but the development is 7.3.1 and I ran the
tests on 7.3.1.

It is courios that on 7.3.1 the query is not constantly bad.
>From time to time it is running well.

regards,
ivan.
Tom Lane wrote:

> pginfo <[EMAIL PROTECTED]> writes:
> > I am using pg 7.3.3 on RH 7.3,
>
> Are you certain the server is 7.3.3?  This looks like a mergejoin
> estimation bug that was present in 7.3 and 7.3.1, but should be fixed
> in 7.3.2 and later.
>
> If it is 7.3.3, I'd like to see the pg_stats rows for
> a_acc.ids_vid_doc and a_vid_doc.ids.
>
> regards, tom lane
>
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Re: [PERFORM] bad join performance

2003-08-18 Thread Stephan Szabo

On Mon, 18 Aug 2003, pginfo wrote:

> Hi ,
> I am using pg 7.3.3 on RH 7.3,
> dual Athlon
> 1 GB RAM.
>
> I have 2 tables a_acc and a_vid_doc (all PK are int).
>
> sizes:
>
>  select count(IDS) from a_acc;
>   count
> -
>  1006772
>
> select count(IDS) from a_vid_doc;
>  count
> ---
> 25
>
> I have problem with the join ot this tables.
> I tryed this examples:
>
>  explain analyze select G.IDS  from A_ACC G   join A_VID_DOC VD
> ON(G.IDS_VID_DOC=VD.IDS)  WHERE G.IDS = 1338673 ;

In general the best index on A_ACC for this kind of query might
be on on A_ACC(IDS, IDS_VID_DOC).  That should allow you to search
by IDS value but still get a sorted order of IDS_VID_DOC to help
the join.


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Re: [PERFORM] bad join performance

2003-08-18 Thread Tom Lane
pginfo <[EMAIL PROTECTED]> writes:
> I am using pg 7.3.3 on RH 7.3,

Are you certain the server is 7.3.3?  This looks like a mergejoin
estimation bug that was present in 7.3 and 7.3.1, but should be fixed
in 7.3.2 and later.

If it is 7.3.3, I'd like to see the pg_stats rows for 
a_acc.ids_vid_doc and a_vid_doc.ids.

regards, tom lane

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