Re: More schema queries - Mailing list pgsql-hackers

From Tom Lane
Subject Re: More schema queries
Date
Msg-id 23101.1021676471@sss.pgh.pa.us
Whole thread Raw
In response to Re: More schema queries  ("Dave Page" <dpage@vale-housing.co.uk>)
Responses Re: More schema queries
List pgsql-hackers
"Dave Page" <dpage@vale-housing.co.uk> writes:
> It doesn't work quite like that anyway.

Oh, so essentially you want to simulate the namespace search on the
application side.  I see.

> Anyway, current_schemas() seems ideal, thanks.

It may not be exactly what you need, because it doesn't tell you about
implicitly searched schemas --- which always includes pg_catalog and
will include a temp namespace if you've activated one.  For instance,
if current_schemas claims the search path is

regression=> select current_schemas();current_schemas
-----------------{tgl,public}
(1 row)

then the real path is effectively {pg_catalog,tgl,public}, or possibly
{pg_temp_NNN,pg_catalog,tgl,public}.

There was already some discussion about making a variant version of
current_schemas() that would tell you the Whole Truth, including the
implicitly searched schemas.  Seems like we'd better do that; otherwise
we'll find people hardwiring knowledge of these implicit search rules
into their apps, which is probably a bad idea.

Anyone have a preference about what to call it?  I could see making a
version of current_schemas() that takes a boolean parameter, or we
could choose another function name for the implicit-schemas-too version.


>> Curious.  I have not noticed much of any change in postmaster 
>> startup time on Unix.  Can you run a profile or something to 
>> see where the time is going?

> Probably, but I'd need hand-holding as I don't have a clue how to do
> that.

I'm not sure how to do it on Cygwin, either.  On Unix you'd build a
profilable backend executable usingcd pgsql/src/backendgmake cleangmake PROFILE="-pg" all
install same, run it, and then use gprof on the gmon.out file dumped
at postmaster termination.  Dunno if it has to be done differently
on Cygwin.
        regards, tom lane


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