BUG #13742: postgres deletes needed files in pg_clog

The following bug has been logged on the website:

Bug reference:      13742
Logged by:          Roland Otta
Email address:      roland.otta@hotmail.com
PostgreSQL version: 9.3.1
Operating system:   Red Hat Enterprise Linux Server release 6.4
Description:

Hi there,

we have a pretty critical problem with our postgres installation.

When trying to dump a database, or when creating some queries (like select
count(*) from table;) we get the following error:

2015-10-28 06:50:45.313 GMT @ 51639  ERROR:  could not access status of
transaction 67976792
2015-10-28 06:50:45.313 GMT @ 51639  DETAIL:  Could not open file
"pg_clog/0040": No such file or directory.

When we try to restore the missing files of the pg_clog directory they get
deleted again immediately.

The following is shown in the postgres-log when enabling debug5 log level:

2015-10-27 23:50:23.682 GMT @ 15294  DEBUG:  SlruScanDirectory invoking
callback on pg_clog/0040
2015-10-27 23:50:23.682 GMT @ 15294  DEBUG:  removing file "pg_clog/0040"

so it seems the file is getting deleted by some housekeeping task even if
that file is needed.

thanks in advance.

br,
roland