Try 'set enable-mergejoin=false' and see if you get a hashjoin.
- Luke
----- Original Message -----
From: pgsql-performance-owner@xxxxxxxxxxxxxx <pgsql-performance-owner@xxxxxxxxxxxxxx>
To: Richard Huxton <dev@xxxxxxxxxxxx>
Cc: pgsql-performance@xxxxxxxxxxxxxx <pgsql-performance@xxxxxxxxxxxxxx>
Sent: Fri May 16 04:00:41 2008
Subject: Re: [PERFORM] Join runs for > 10 hours and then fills up >1.3TB of disk space
I'm expecting 9,961,914 rows returned. Each row in the big table
should have a corresponding key in the smaller tale, I want to
basically "expand" the big table column list by one, via adding the
appropriate key from the smaller table for each row in the big table.
It's not a cartesion product join.
On May 16, 2008, at 1:40 AM, Richard Huxton wrote:
> kevin kempter wrote:
>> Hi List;
>> I have a table with 9,961,914 rows in it (see the describe of
>> bigtab_stats_fact_tmp14 below)
>> I also have a table with 7,785 rows in it (see the describe of
>> xsegment_dim below)
>> I'm running the join shown below and it takes > 10 hours and
>> eventually runs out of disk space on a 1.4TB file system
>
>> QUERY PLAN
>> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Merge
>> Join (cost=1757001.74..73569676.49 rows=3191677219 width=118)
>
> Dumb question Kevin, but are you really expecting 3.2 billion rows
> in the result-set? Because that's approaching 400GB of result-set
> without any overheads.
>
> --
> Richard Huxton
> Archonet Ltd
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