Re: Excessive memory used for INSERT

From: Alessandro Ipe <Alessandro(dot)Ipe(at)meteo(dot)be>
To: Torsten Zuehlsdorff <mailinglists(at)toco-domains(dot)de>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Excessive memory used for INSERT
Date: 2014-12-17 16:57:51
Message-ID: 35486133.28l5a59Zd7@snow.oma.be
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Hi Torsten,

Thanks for your answer.

I have modified
(SELECT * FROM upsert)
to
(SELECT * FROM upsert WHERE slot=to_timestamp('201212032145', 'YYYYMMDDHH24MI') and MSG=2)
according to your suggestion to reduce the result-set to a single row. However, the INSERT process is still consuming the same amount of RAM.

Regards,

Alessandro.

On Wednesday 17 December 2014 16:26:32 Torsten Zuehlsdorff wrote:
> Hello Alessandro,
>
> > 2014-12-15 17:54:07 GMT DETAIL: Failed process was running: WITH upsert
> > AS (update MSG set
> > (slot,MSG,HRV,VIS006,VIS008,IR_016,IR_039,WV_062,WV_073,IR_087,IR_097,IR_1
> > 08,IR_120,IR_134,PRO,EPI,CLM,TAPE) = (to_timestamp('201212032145',
> > 'YYYYMMDDHH24MI'),2,'\xffffff','\xff','\xff','\xff','\xff','\xff','\xff','
> > \xff','\xff','\xff','\xff','\xff','\x01','\x01','\x7f','LTO5_020') where
> > slot=to_timestamp('201212032145', 'YYYYMMDDHH24MI') and MSG=2 RETURNING
> > *) insert into MSG
> > (slot,MSG,HRV,VIS006,VIS008,IR_016,IR_039,WV_062,WV_073,IR_087,IR_097,IR_1
> > 08,IR_120,IR_134,PRO,EPI,CLM,TAPE) select to_timestamp('201212032145',
> > 'YYYYMMDDHH24MI'),2,'\xffffff','\xff','\xff','\xff','\xff','\xff','\xff','
> > \xff','\xff','\xff','\xff','\xff','\x01','\x01','\x7f','LTO5_020' WHERE
> > NOT EXISTS (SELECT * FROM upsert);
>
> How many rows is "(SELECT * FROM upsert)" returning? Without knowing
> more i would guess, that the result-set is very big and that could be
> the reason for the memory usage.
>
> I would add an WHERE clause to reduce the result-set (an correct index
> can fasten this method even more).
>
> Greetings,
> Torsten

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