From: | Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> |
---|---|
To: | pgsql-hackers(at)postgreSQL(dot)org |
Subject: | sort on huge table |
Date: | 1999-10-13 10:03:20 |
Message-ID: | 199910131003.TAA06423@srapc451.sra.co.jp |
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Lists: | pgsql-hackers |
I came across problems with sorting a huge (2.4GB) table.
o it took 46 minutes to complete following query:
select * from test2 order by i desc limit 100;
to get 0 results.
i|t
-+-
(0 rows)
I assume this is a failure.
note: this is Pentium III x2 with 512MB RAM running RedHat Linux 6.0.
o I got NOTICE: BufFileRead: should have flushed after writing
at the very end of the processing.
o it produced 7 sort temp files each having size of 1.4GB (total 10GB)
Here is the table I used for testing(no index):
CREATE TABLE test2 (
i int4,
t text);
This has 10000000 records and the table file sizes are:
$ ls -ls test2*
1049604 -rw------- 1 postgres postgres 1073741824 Oct 4 18:32 test2
1049604 -rw------- 1 postgres postgres 1073741824 Oct 5 01:19 test2.1
327420 -rw------- 1 postgres postgres 334946304 Oct 13 17:40 test2.2
--
Tatsuo Ishii
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