Re: Partition insert trigger using C language

From: Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>
To: Matheus de Oliveira <matioli(dot)matheus(at)gmail(dot)com>
Cc: pgsql-performance <pgsql-performance(at)postgresql(dot)org>, Charles Gomes <charlesrg(at)outlook(dot)com>
Subject: Re: Partition insert trigger using C language
Date: 2013-01-11 10:19:55
Message-ID: 50EFE74B.9040007@vmware.com
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On 10.01.2013 21:48, Matheus de Oliveira wrote:
> I have made a small modification to keep the plans, and it got from
> 33957.768ms to 43782.376ms.

If I'm reading results.txt correctly, the avg runtimes are:

C and SPI_execute_with_args: 58567.708 ms
C and SPI_(prepare/keepplan/execute_plan): 43782.376 ms
C and heap_insert: 33957.768 ms

So switching to prepared plans helped quite a lot, but it's still slower
than direct heap_inserts.

One thing that caught my eye:

> CREATE OR REPLACE FUNCTION partition_insert_trigger_spi()
> RETURNS trigger
> LANGUAGE C
> VOLATILE STRICT
> AS 'partition_insert_trigger_spi','partition_insert_trigger_spi'
> SET DateStyle TO 'ISO';

Calling a function with SET options has a fair amount of overhead, to
set/restore the GUC on every invocation. That should be avoided in a
performance critical function like this.

- Heikki

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