On Mon, Jul 18, 2016 at 9:43 AM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Merlin Moncure <mmonc...@gmail.com> writes: > > BTW, while the fix does address the cleanup performance issue, it's > > still the case that anonymous code blocks burn up lots of resident > > memory (my 315k example I tested with ate around 8gb IIRC) when run > > like this. My question is, if the pl/pgsql code block is anonymous > > and not in some kind of a loop, why bother caching the plan at all? > > Nobody got around to it. Also, as you note, it's not as simple as > "don't cache if in a DO block". You'd need to track whether you were > inside any sort of looping construct. Depending on how difficult > that turned out to be, it might add overhead to regular functions > that we don't want. Agreed. And from the structures themselves it is not really easy to detect if inside of a loop, the toplevel, while, for and if all use the same statement block and call exec_stmts(), which in turn calls exec_stmt() for each element in that list. It is not impossible to add a flag, set at PL compile time, to that element and check it every time, the statement is executed. But such a change definitely needs more testing and probably won't qualify for backpatching. In the meantime, would it be appropriate to backpatch the double linking of memory context children at this time? I believe it has had plenty of testing in the 9.6 cycle to be sure it didn't break anything. Regards, Jan -- Jan Wieck Senior Postgres Architect http://pgblog.wi3ck.info
