From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | ron(at)yellowbank(dot)com, Ronald Peterson <ron(at)hub(dot)yellowbank(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: extra function calls from query returning composite type |
Date: | 2014-12-29 15:54:49 |
Message-ID: | 6792.1419868489@sss.pgh.pa.us |
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Lists: | pgsql-general |
Ronald Peterson <ron(at)hub(dot)yellowbank(dot)com> writes:
> I added a 'raise notice' to a plpgsql function I was working on
> recently, and noticed that my notification was being raised more often
> than I expected. The notification is raised in a function ('getone'
> in my example below) that returns a single composite value. This
> function is then called by another function ('getset') that returns a
> setof that composite value. It appears that 'getone' is called once
> for each column of my composite type. I whittled this down to the
> following example.
> I get the expected result from my query, but I don't understand (what
> appear to be) the extra function calls.
This:
> SELECT (getone(id)).*
is implemented as SELECT (getone(id)).foo, (getone(id)).bar
If you're using 9.3 or later you could avoid that by recasting the
call as LATERAL, ie
SELECT go.*
FROM dat, LATERAL getone(id) AS go
WHERE set = setid;
regards, tom lane
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