From 70066eb1a1adb4d1ac608c1127bbb3139fa09942 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 17 Jan 2008 21:21:50 +0000
Subject: [PATCH] Insert into getCopyDataMessage() the same logic that already
existed in the main code path for enlarging libpq's input buffer in one swoop
when needing to read a long data message. Without this, the code will double
the buffer size, read more data, notice it still hasn't got the whole
message, and repeat till it finally has a large enough buffer. Which wastes
a lot of data-moving effort and also memory (since malloc probably can't do
anything very useful with the freed-up smaller buffers). Not sure why this
wasn't there already; certainly the COPY data path is a place where we're
quite likely to see long data messages. I'm not backpatching though, since
this is just a marginal performance issue rather than a real bug.
---
src/interfaces/libpq/fe-protocol3.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index c40868805f3..89c0d5018f0 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-protocol3.c,v 1.33 2008/01/15 22:18:20 tgl Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-protocol3.c,v 1.34 2008/01/17 21:21:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1305,7 +1305,24 @@ getCopyDataMessage(PGconn *conn)
}
avail = conn->inEnd - conn->inCursor;
if (avail < msgLength - 4)
+ {
+ /*
+ * Before returning, enlarge the input buffer if needed to hold
+ * the whole message. See notes in parseInput.
+ */
+ if (pqCheckInBufferSpace(conn->inCursor + msgLength - 4, conn))
+ {
+ /*
+ * XXX add some better recovery code... plan is to skip over
+ * the message using its length, then report an error. For the
+ * moment, just treat this like loss of sync (which indeed it
+ * might be!)
+ */
+ handleSyncLoss(conn, id, msgLength);
+ return -2;
+ }
return 0;
+ }
/*
* If it's a legitimate async message type, process it. (NOTIFY
--
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