Bug #782: clog files disappear after 'vacuum;' - Mailing list pgsql-bugs

From pgsql-bugs@postgresql.org
Subject Bug #782: clog files disappear after 'vacuum;'
Date
Msg-id 20020927011739.A65DC476268@postgresql.org
Whole thread Raw
Responses Re: Bug #782: clog files disappear after 'vacuum;'  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-bugs
Steven Wilton (steven.wilton@team.eftel.com) reports a bug with a severity of 2
The lower the number the more severe it is.

Short Description
clog files disappear after 'vacuum;'

Long Description
We are having a problem with our pg_clog files disappearing after a vacuum command is run.  We have a database called
"traffic"which has tables created every half hour, and after each table is older than 8 hours, we drop them.  The
'postgres'user does not have any access to the traffic database, and the 'collector' user only has access to the
trafficdatabase. 

If either the 'collector' or 'postgres' user runs a vacuum command, most of the files in the pg_clog directory
disappear.  After the vacuum, if you try to drop certain tables, you get the following error: 

traffic=> drop table raw_traf_573808;
FATAL 2:  open of /var/lib/postgres/data/pg_clog/0005 failed: No such file or directory
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.


If I disconnect from postgres, recreate the pg_clog file (from /dev/zero), I get the following error:

traffic=> drop table raw_traf_573808;
ERROR:  DeleteTypeTuple: type "raw_traf_573808" does not exist

traffic=> \d raw_traf_573808
FATAL 2:  open of /var/lib/postgres/data/pg_clog/0000 failed: No such file or directory
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.

At this stage, I need to create all clog files (ie from 0000 to 0005).  Once I create the clog files, I get the
followingoutput: 

traffic=> \d raw_traf_573808
                 Table "raw_traf_573808"
        Column         |   Type   |      Modifiers
-----------------------+----------+----------------------
 start_time            | integer  | not null
 stop_time             | integer  | not null
 source_ip             | integer  | not null
 dest_ip               | integer  | not null
 source_port           | smallint | not null
 dest_port             | smallint | not null
 router_ip             | integer  | not null
 input_interface_type  | smallint | not null
 output_interface_type | smallint | not null
 bytes                 | integer  | not null
 swap                  | boolean  | not null default '0'
 flags                 | smallint | not null

traffic=> drop table raw_traf_573808;
ERROR:  DeleteTypeTuple: type "raw_traf_573808" does not exist

If I delete the postgres installation, and re-create all tables, the system works fine for a while (ie the tables get
created,dropped without a problem).  After the postgres system has been running for a while, we will eventually lose
oneof the clog files, and end up with tables in the database that we can not drop. 

We are running postgres 7.2.1 under a debian 3.0(woody) linux system with a 2.4.18 kernel.

any help would be appreaciated.

thanks

Steven

Sample Code


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