pgss_dealloc: fails with `--dbservice` / service target must have pg_stat_statements

[Krysztophe]

1. With --dbservice, it complains that there is no DB:

FATAL: you must give one database with service "pgss_dealloc".

Patch is coming to allow that.

2. If the database in the service is template1 or postgres as often,
   it is not possible to query a pg_stat_statements installed in another DB.

That may be a limit. I don't know of a work-around.

Perhaps is it possible to --dbinclude or another parameter to make another connection once connected, but this may be overkill.

[Krysztophe]

For 1), see #412

[gleu]

Using a service should be allowed. Thanks for the patch, I'll test it.

On the second part, making it connect to another database, I pretty much don't like it. We would have to try to connect to X databases before connecting to the right one? each time this service is used? That will consume resources for no good reason.

[Krysztophe]

Some services already connect to all available databases (btree/table_bloat, extensions_versions…)

For this one, only one DB would suffice.

[gleu]

Yeah, only one DB, but you need to find the one. And for this, you may have to connect to quite a lot of databases.

I did some tests of your patch, and it seems to be working.

[gleu]

I gave it another thought and, as much as I want the first part, I don't want the second part. To make it easy to someone lazy enough to not specify the right database, we would add connections to many databases each time we ran this service? doesn't seem fair to me.