Re: Slow update statement - Mailing list pgsql-performance

From Patrick Hatcher
Subject Re: Slow update statement
Date
Msg-id 42F6E118.20206@comcast.net
Whole thread Raw
In response to Re: Slow update statement  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
At the time this was the only process running on the box so I set
sort_mem= 228000;
It's a 12G box.

Tom Lane wrote:

>Patrick Hatcher <pathat@comcast.net> writes:
>
>
>> Hash Join  (cost=1246688.42..4127248.31 rows=12702676 width=200)
>>   Hash Cond: ("outer".cus_num = "inner".cus_nbr)
>>   ->  Seq Scan on bcp_ddw_ck_cus b  (cost=0.00..195690.76 rows=12702676
>>width=16)
>>   ->  Hash  (cost=874854.34..874854.34 rows=12880834 width=192)
>>         ->  Seq Scan on cdm_ddw_customer  (cost=0.00..874854.34
>>rows=12880834 width=192)
>>
>>
>
>Yipes, that's a bit of a large hash table, if the planner's estimates
>are on-target.  What do you have work_mem (sort_mem if pre 8.0) set to,
>and how does that compare to actual available RAM?  I'm thinking you
>might have set work_mem too large and the thing is now swap-thrashing.
>
>            regards, tom lane
>
>
>

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