From: Pierre C <lists@peufeu.com>
To: Mario Splivalo <mario.splivalo@megafon.hr>
Cc: Mladen Gogala <mladen.gogala@vmsinfo.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: SELECT INTO large FKyed table is slow
Date: Wed, 01 Dec 2010 09:23:23 +0100
Message-ID: <op.vm0z89fgeorkce@apollo13> (raw)
In-Reply-To: <4CF5FEA9.3000900@megafon.hr>
References: <4CF24103.8030209@megafon.hr>
<4CF5259C.8000306@vmsinfo.com>
<4CF59017.1090705@megafon.hr>
<op.vm0fb7z4eorkce@apollo13>
<4CF5FEA9.3000900@megafon.hr>
> Just once.
OK, another potential problem eliminated, it gets strange...
> If I have 5000 lines in CSV file (that I load into 'temporary' table
> using COPY) i can be sure that drone_id there is PK. That is because CSV
> file contains measurements from all the drones, one measurement per
> drone. I usualy have around 100 new drones, so I insert those to drones
> and to drones_history. Then I first insert into drones_history and then
> update those rows in drones. Should I try doing the other way around?
No, it doesn't really matter.
> Although, I think I'm having some disk-related problems because when
> inserting to the tables my IO troughput is pretty low. For instance,
> when I drop constraints and then recreate them that takes around 15-30
> seconds (on a 25M rows table) - disk io is steady, around 60 MB/s in
> read and write.
>
> It just could be that the ext3 partition is so fragmented. I'll try
> later this week on a new set of disks and ext4 filesystem to see how it
> goes.
If you CLUSTER a table, it is entirely rebuilt so if your disk free space
isn't heavily fragmented, you can hope the table and indexes will get
allocated in a nice contiguous segment.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: lists@peufeu.com, mario.splivalo@megafon.hr, mladen.gogala@vmsinfo.com
Subject: Re: SELECT INTO large FKyed table is slow
In-Reply-To: <op.vm0z89fgeorkce@apollo13>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox