From: | Mario Splivalo <mario(dot)splivalo(at)megafon(dot)hr> |
---|---|
To: | jd(at)commandprompt(dot)com |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: SELECT INTO large FKyed table is slow |
Date: | 2010-12-01 07:53:46 |
Message-ID: | 4CF5FF0A.9040605@megafon.hr |
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Thread: | |
Lists: | pgsql-performance |
On 12/01/2010 02:47 AM, Joshua D. Drake wrote:
> On Sun, 2010-11-28 at 12:46 +0100, Mario Splivalo wrote:
>> The database for monitoring certain drone statuses is quite simple:
>>
>
>> This is the slow part:
>> INSERT INTO drones_history (sample_id, drone_id, drone_log_notice,
>> drone_temperature, drone_pressure)
>> SELECT * FROM tmpUpdate;
>>
>> For 100 rows this takes around 2 seconds. For 1000 rows this takes
>> around 40 seconds. For 5000 rows this takes around 5 minutes.
>> For 50k rows this takes around 30 minutes! Now this is where I start lag
>> because I get new CSV every 10 minutes or so.
>
> Have you considered making the foreign key check deferrable?
>
Yes, as Mladen Gogala had advised. No noticable change in performance -
it's still slow :)
But, just for the sake of clarification - I tought that DEFERRABLE would
matter if I do a lot of INSERTs, inside a FOR loop or something like
that. Since I'm doing INSERT INTO ... SELECT, does it makes any difference?
Mario
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