Make functions.c mostly run in a short-lived memory context. Previously, much of this code ran with CurrentMemoryContext set to be the function's fcontext, so that we tended to leak a lot of stuff there. Commit 0dca5d68d dealt with that by releasing the fcontext at the completion of each SQL function call, but we'd like to go back to the previous approach of allowing the fcontext to be query-lifespan. To control the leakage problem, rearrange the code so that we mostly run in the memory context that fmgr_sql is called in (which we expect to be short-lived). Notably, this means that parsing/planning is all done in the short-lived context and doesn't leak cruft into fcontext.
This patch also fixes the allocation of execution_state records so that we don't leak them across executions. I set that up with a re-usable array that contains at least as many execution_state structs as we need for the current querytree. The chain structure is still there, but it's not really doing much for us, and maybe somebody will be motivated to get rid of it. I'm not though. This incidentally also moves the call of BlessTupleDesc to be with the code that creates the JunkFilter. That doesn't make much difference now, but a later patch will reduce the number of times the JunkFilter gets made, and we needn't bless the results any more often than that. We still leak a fair amount in fcontext, particularly when executing utility statements, but that's material for a separate patch step; the point here is only to get rid of unintentional allocations in fcontext. Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/595d1efeda11186ac6850f5e0bfec877da363e1e Modified Files -------------- src/backend/executor/functions.c | 153 ++++++++++++++++++++++++--------------- 1 file changed, 95 insertions(+), 58 deletions(-)
