"Alon Goldshuv" <[EMAIL PROTECTED]> writes: > Please help me understand this better. It appears to me that when the > client->backend pipe fills up, pqSendSome() consumes any incoming > NOTICE/WARNING messages before waiting, which should prevent deadlock.
Hm, I had forgotten that the low-level pqSendSome routine does that. That makes the PQconsumeInput call in PQputCopyData redundant (or almost; see below). The parseInput call is still needed, because it's there to pull NOTICE messages out of the input buffer and get rid of them, rather than possibly having the input buffer grow to exceed memory. But when there's nothing for it to do, parseInput is cheap enough that there's no real need to bypass it. In short, if you just remove the PQconsumeInput call I think you'll find that it does what you want. The only case where it's helpful to have it there is if there's a incomplete message in the input buffer, as parseInput isn't quite so fast if it has to determine that the message is incomplete. Without the PQconsumeInput call, the incomplete-message state could persist for a long time, and you'd pay the parseInput overhead each time through PQputCopyData. However, that's certainly not the normal situation, so I think we could leave that case slightly pessimal. It's certainly true that that path in parseInput is a lot faster than a kernel call, so it'd still be better than it is now. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match