Re: BUG #15321: XMLTABLE leaks memory like crazy

>>>>> "Pavel" == Pavel Stehule <pavel.stehule@gmail.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)