Re: BUG #15321: XMLTABLE leaks memory like crazy

>>>>> "Pavel" == Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:

>> But that's not "immediately" because tfuncLoadRows is looping over
>> the FetchRow call, and calling GetValue for each column in that row,
>> and in your version it is _not cleaning up memory in that loop_.

Pavel> ok, now I am maybe understand to your motivation.

Pavel> Usually, loading row should be memory cheap operation, but sure
Pavel> some bytes it can take.

Yes, it'll usually be small, but you shouldn't assume that (and some
type input functions may use more memory than you think, since doing a
lot of retail pfree() calls can really slow things down).

Pavel> Then I don't like too much using ecxt_per_tuple_memory for this.

It's there, it has the right lifetime, allocating another one just for
this is a waste. Furthermore, this is the same pattern that FunctionScan
uses, so it's more consistent.

Pavel> Or do better comments about using this memory context for very
Pavel> short life task, please.

What specifically do you think needs explaining?

Attached patch is the same logic as before but with more comments.

--
Andrew (irc:RhodiumToad)