Received: from makus.postgresql.org (makus.postgresql.org [98.129.198.125]) by mail.postgresql.org (Postfix) with ESMTP id 61F0F4BB8EB for ; Wed, 4 Apr 2012 12:53:02 -0300 (ADT) Received: from mail-pb0-f46.google.com ([209.85.160.46]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1SFSW5-0006Zh-BJ for pgsql-performance@postgresql.org; Wed, 04 Apr 2012 15:53:02 +0000 Received: by pbcun15 with SMTP id un15so429667pbc.19 for ; Wed, 04 Apr 2012 08:52:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:reply-to:subject:x-priority:x-guid:x-has-attach :x-mailer:mime-version:message-id:content-type; bh=TDhodLHzJ/icq7ydk8hm1r7X4LiapgNODbludonAqyE=; b=XRr0pxXjOnQIojKRrT4gI7/2BwrdChso0h6iAS7qjUGMkAjfWhtzC+9XPJib7u4tbp uBvj69lLvG96nh0V43uj1RRLwoZbEncWokjPC3VURFHPoAIWstOjlERJcTzcUZJy2v+5 2CtBZOJ/tXmBMmPodptNBSVzjjHL+MaOObldIQO6dWc4UxosSHaO8C0AY00mfr5rQS8T Jhfzy5OyQqc5vfxD6gbhhxHUXskdX/5wvBBEorECRIbCDtYAdgCvg6wrOd/2nqze+bvt x7e/+fC66JDW3fbGt4plTctbEfjidKhYWuQ4lAAYv1J9hi/afFKompftabagADlQpubb 67Qw== Received: by 10.68.197.65 with SMTP id is1mr15561895pbc.70.1333554768310; Wed, 04 Apr 2012 08:52:48 -0700 (PDT) Received: from imsuperman-PC ([113.224.202.112]) by mx.google.com with ESMTPS id h10sm891842pbe.12.2012.04.04.08.52.45 (version=SSLv3 cipher=OTHER); Wed, 04 Apr 2012 08:52:47 -0700 (PDT) Date: Wed, 4 Apr 2012 23:52:51 +0800 From: superman0920 To: pgsql-performance Reply-To: superman0920 Subject: about multiprocessingmassdata X-Priority: 3 X-GUID: 31691221-7CF6-45E8-86B0-9F518E17D114 X-Has-Attach: no X-Mailer: Foxmail 7.0.1.88[cn] Mime-Version: 1.0 Message-ID: <2012040423524938620013@gmail.com> Content-Type: multipart/alternative; boundary="----=_001_NextPart452440284114_=----" X-Pg-Spam-Score: -2.3 (--) X-Archive-Number: 201204/41 X-Sequence-Number: 46687 This is a multi-part message in MIME format. ------=_001_NextPart452440284114_=---- Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: base64 SGkgbGlzdCENCg0KaSBoYXZlIGEgdGFibGUgd2hpY2ggaGFzIDg1MDAwMDAgcm93cyByZWNvcmRz LiBpIHdyaXRlIGEgamF2YSBwcm9ncmFtIHRvIHVwZGF0ZSB0aGVzZSByZWNvcmRzLiANCmkgdXNl IDEwMCB0aHJlYWRzIHRvIHVwZGF0ZSB0aGUgcmVjb3Jkcy4gRm9yIGV4YW1wbGUsIHRocmVhZC0x IHVwZGF0ZSAxfjg1MDAwIHJlY29yZHM7IHRocmVhZC0yIHVwZGF0ZSA4NTAwMX4xNzAwMDAgYW5k IHNvIG9uLg0KVGhlIHVwZGF0ZSBzcWwncyBhaW0gaXMgcmVtb3ZlIHRoZSBzcGFjZSBpbiB0aGUg Y29sdW1uIGFuZCBpdCBpcyBzaW1wbGU6IHVwZGF0ZSBwb2kgc2V0IHB5PXJlcGxhY2UocHksJyAn LCcnKSB3aGVyZSBpZD0/Ow0KDQpCeSB0aGUgcHJvZ3JhbSBsb2csIGkgZmluZCB0aGUgZGF0YWJh c2Ugb2YgcHJvY2Vzc2luZyBkYXRhIHNwZWVkIHNvIHNsb3csIHBlciB0aHJlYWQgdXBkYXRpbmcg MTAwMCByb3dzIG5lZWQgdGFrZSAyNjBzLg0KDQpCVFc6ICBUaGUgUEcgU2VydmVyIGlzIHJ1bm5p bmcgb24gYSBQQy4gVGhlIFBDJ3MgdG90YWwgbWVtb3J5IGlzIDJHIGFuZCBDUFUgaXMgIkludGVs KFIpIENvcmUoVE0pMiBEdW8gRTc1MDAgMi45M0dIeiIuDQpXaGVuIHRoZSBwcm9ncmFtJ3MgcnVu bmluZywgQ1BVIGp1c3QgYmUgdXNlZCAxJSBhbmQgTWVtb3J5ICBsZWZ0IDExMk1CLg0KDQpJcyB0 aGUgUEMgY29uZmlndXJhdGlvbiB0b28gbG93IGNhdXNlIHRoZSBwcm9ibGVtID8NCg0KUGxlYXNl IGhlbHAgfn4NCg0KDQpUaGFua3MgZm9yIGFueSB0aXBzLA0KDQoNCg0Kc3VwZXJtYW4wOTIw ------=_001_NextPart452440284114_=---- Content-Type: text/html; charset="gb2312" Content-Transfer-Encoding: quoted-printable

Hi list!

i have a table which has 8500000 rows records. i write a java pr= ogram=20 to update these records.

i use 100 threads to update the records. For example, thread-1 update= =20 1~85000 records; thread-2 update 85001~170000 and so on.

The update sql's aim is remove the space in the column and it=20 is simple: update poi set py=3Dreplace= (py,'=20 ','') where id=3D?;

By the program log, i find the databas= e of=20 processing data speed so slow, per thread updating 1000 rows need take=20 260s.

BTW: The PG Server is runni= ng on a=20 PC. The PC's total memory is 2G and CPU is "Intel(R) Core(TM)2 Duo E7500=20 2.93GHz".

When the program's running, CPU just b= e used=20 1% and Memory left 112MB.

Is the PC configuration too low cause the problem ?

Please help ~~

Thanks=20 for any tips,

superman0920

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