|From:||Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>|
|To:||David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>|
|Cc:||Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Robert Haas <robertmhaas(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>|
|Subject:||Re: POC: converting Lists into arrays|
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>> * Rationalize places that are using combinations of list_copy and
>> list_concat, probably by inventing an additional list-concatenation
>> primitive that modifies neither input.
> I poked around to see what we have in this department. There seem to
> be several identifiable use-cases:
> [ ... analysis ... ]
Here's a proposed patch based on that. I added list_concat_copy()
and then simplified callers as appropriate.
It turns out there are a *lot* of places where list_concat() callers
are now leaking the second input list (where before they just leaked
that list's header). So I've got mixed emotions about the choice not
to add a variant function that list_free's the second input. On the
other hand, the leakage probably amounts to nothing significant in
all or nearly all of these places, and I'm concerned about the
readability/understandability loss of having an extra version of
list_concat. Anybody have an opinion about that?
Other than that point, I think this is pretty much good to go.
regards, tom lane
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