> Currently, we have been having a problem with some kind of corruption of
> the pg_database file. We are using the database on a limited number of
> writes storage medium. (Compact Flash Card) So that we don't always
> write to the flash, and because we don't care about some of the data, part
> of the database is kept in RAM on a ram file system. We have two
> databases on disk. One database called config, the other the standard
> template1. These are kept in /var/lib/pgsql_base_slave. We have a
> properly init'ed database in /var/lib/pgsql/. When postgresql starts up
> via the init scripts, we create a RAM file system on /var/lib/pgsql/base/,
> and then we create symlinks to the config and template1 databases.
>
> The next set of steps is where we sometimes run into trouble. At
> this point in the init script, we start up the postmaster. Next we do a
> createdb products, where products is the actual name of the database.
> This works fine. Next, we attempt to access the database using psql to
> create a set of tables. This is where sometimes we run into a problem.
> Normally, this works fine, but sometimes we get the error
>
> "Database 'products', OID nnn, has disappeared from pg_database"
>
> where nnn is some number, and forever afterwards we can't access a
> database with that name. Removing and recreating the database doesn't
> help. Neither does vacuuming it. If we delete the whole pgsql directory,
> and recreate it, then use initdb on it, everything is fresh and working
> again, but obviously this isn't a good solution, since we have to recreate
> all the databases, tables, and data.
>
> On the shutdown side, we do a deletedb to remove the products
> database before we shutdown the postmaster. Once that is complete, we do
> a shutdown.
>
> If you need a short list of the startup procedure that is above, here it
> is in a psuedocode fashion.
>
> mount ram drive.
> make symlinks to config and template1 databases
> startup postmaster
> createdb products
> create some tables in products
>
> ... normal operation ...
>
> ... shutdown process
> dropdb products
> shutdown postmaster.
>
>
> I am assuming that some kind of corruption has occured within
> pg_database file, but I don't have the expertise to find where the problem
> is occuring. Any help you can provide would be greatly appreciated.
>
> I am including the init script used.
> <<postgresql.txt>>
>
> Sandy Barnes
> Honeywell
> Business & General Aviation Engineering
> One Technology Center
> 23500 West 105th Street
> Olathe, KS. 66061
> tel 913.712.2027
> fax 913.712.1347
> email sandy(dot)barnes(at)honeywell(dot)com
>
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end