From: Yannick Monclin <yannick.monclin@univ-reims.fr>
To: pgsql-admin@postgresql.org
Subject: extend column limit with blocksize does not work
Date: Thu, 26 Jan 2012 13:32:28 +0100
Message-ID: <4F2147DC.1010002@univ-reims.fr> (raw)
Hi,
I use the query survey software "Limesurvey", when this sofware build
some complex survey, it's necessary to have more than 1600 columns in
one table. So, i have used this parameter (configure
--with-blocksize=32) to build my last postgresql (9.1.2). Compilation
process succeed. I create a DB with initdb (i change
posgresql.conf.sample --> shared_buffers = 32MB in order to have no
errors when initdb create the database, default value was not set and
initdb stop).
I create an user and a test database, with no problem.
In order to testing, i have a batch with a loop to alter table and add
many columns... my batch stops at 1600 columns wtih this error :
ERROR: tables can have at most 1600 columns
I don't understand why, it's seems me all is ok, did you have an idea ?
Can i have more than 1600 columns ? According to the documentation,
default limit with blocksize 8kb are 250 to 1600, but with a blocksize
to 32Kk limits are quadrupled, it's right ?
Thanks in advance,
Yannick
Platform : Linux debian 64b
pg_controldata output :
pg_control version number: 903
Catalog version number: 201105231
Database system identifier: 5701891827790346600
Database cluster state: shut down
pg_control last modified: Thu 26 Jan 2012 11:52:25 AM CET
Latest checkpoint location: 0/188EA08
Prior checkpoint location: 0/188E730
Latest checkpoint's REDO location: 0/188EA08
Latest checkpoint's TimeLineID: 1
Latest checkpoint's NextXID: 0/678
Latest checkpoint's NextOID: 11868
Latest checkpoint's NextMultiXactId: 1
Latest checkpoint's NextMultiOffset: 0
Latest checkpoint's oldestXID: 668
Latest checkpoint's oldestXID's DB: 1
Latest checkpoint's oldestActiveXID: 0
Time of latest checkpoint: Thu 26 Jan 2012 11:52:25 AM CET
Minimum recovery ending location: 0/0
Backup start location: 0/0
Current wal_level setting: minimal
Current max_connections setting: 50
Current max_prepared_xacts setting: 0
Current max_locks_per_xact setting: 64
Maximum data alignment: 8
Database block size: 32768
Blocks per segment of large relation: 32768
WAL block size: 8192
Bytes per WAL segment: 16777216
Maximum length of identifiers: 64
Maximum columns in an index: 32
Maximum size of a TOAST chunk: 8140
Date/time type storage: 64-bit integers
Float4 argument passing: by value
Float8 argument passing: by value
--
Yannick Monclin
Université de Reims Champagne Ardenne
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To: pgsql-admin@postgresql.org
Cc: yannick.monclin@univ-reims.fr
Subject: Re: extend column limit with blocksize does not work
In-Reply-To: <4F2147DC.1010002@univ-reims.fr>
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