Re: cannot read pg_class without having selected a database / is this a bug?

On 4.12.2011 17:10, Tom Lane wrote:
> Tomas Vondra <tv@fuzzy.cz> writes:
>> Anyway, the code I posted does not fail because of pg_stat_activity, it
>> fails because it attempts for find the dbname/username for the backends
>> (read from pg_stat_activity).
> 
> Well, get_database_name tries to do a syscache lookup, and the syscache
> infrastructure isn't working yet.  It is possible to read a shared
> catalog at this stage, but you have to use lower-level access mechanisms
> --- for an example with some comments, look at GetDatabaseTuple in
> postinit.c.

Great, this seems to work perfectly.

What about the pg_stat_activity - is it safe to access that from auth
hook or is that just a coincidence that it works (and might stop working
in the future)?

Tomas