Обсуждение: BUG #8247: Duplicate database names - pg_dump backup fails

The following bug has been logged on the website:

Bug reference:      8247
Logged by:          Paul Macdonald
Email address:      paul.macdonald@ssc-spc.gc.ca
PostgreSQL version: Unsupported/Unknown
Operating system:   Debian Sarge
Description:

Postgres version: 7.4.7-6sarge1


Issue: pg_dump fails due to unexpected duplication of database name
("avipads"). Dropdb will remove one instance of the database name, but
unable to remove the second instance.


Scope: This specific database is used on multiple servers nationally. Three
of our servers have this issue, the majority do not. The issue only affects
our ability to locally backup the "avipads" database. The servers having the
problem are clustered pair systems. The other cluster pair servers do not
have the problem.


   Name    | Owner       | Encoding
-----------+-------------+-----------
 avipads   |             | SQL_ASCII
 avipads   | avimgr      | SQL_ASCII
 rtadb     | rtafbackend | SQL_ASCII
 rtafdb    | rtafbackend | SQL_ASCII
 template0 | postgres    | SQL_ASCII
 template1 | postgres    | SQL_ASCII


When a new version of the database is available for installation, the
installation script does the following steps
a) remove the old database
su - avimgr -c "dropdb --quiet --username=avimgr avipads" || true
b) remove the avimgr user
su - postgres -c "dropuser --quiet avimgr" || true
c) create the avimgr Posgresql user
su - postgres -c "createuser avimgr --no-adduser --createdb --quiet; true"
2> /dev/null
d) install the new database
su - avimgr -c "/apps/avipads/voicedb/restorevoice
/apps/avipads/voicedb/vdb2.5.1.pg"


I would like details on how to successfully remove both "avipads" databases,
in order to have the pg_dump be functional again.

paul.macdonald@ssc-spc.gc.ca writes:
> Postgres version: 7.4.7-6sarge1

Egad.  Not only has 7.4 been EOL for years, but the last release in that
series was 7.4.30.  You are missing many years' worth of bug fixes.
You really, really, really need to get off of that PG version ASAP.

> Issue: pg_dump fails due to unexpected duplication of database name
> ("avipads"). Dropdb will remove one instance of the database name, but
> unable to remove the second instance.

I suspect this is evidence of transaction ID wraparound in the
pg_database catalog.  See if "VACUUM FULL pg_database" makes things
any saner.  (Delete the one database that you're able to get rid of
first.)

            regards, tom lane