dovecot-2.2: imapc: Don't flush prefetch FETCH command before it...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/f8f57dde247d
changeset: 18323:f8f57dde247d
user:      Timo Sirainen <tss at iki.fi>
date:      Wed Mar 11 14:39:52 2015 +0200
description:
imapc: Don't flush prefetch FETCH command before it has mail_prefetch_count number of mails.

diffstat:

 src/lib-storage/index/imapc/imapc-mail-fetch.c |  17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)

diffs (34 lines):

diff -r d21f71ab9f28 -r f8f57dde247d src/lib-storage/index/imapc/imapc-mail-fetch.c
--- a/src/lib-storage/index/imapc/imapc-mail-fetch.c	Wed Mar 11 14:39:26 2015 +0200
+++ b/src/lib-storage/index/imapc/imapc-mail-fetch.c	Wed Mar 11 14:39:52 2015 +0200
@@ -146,7 +146,19 @@
 	}
 	array_append(&mbox->pending_fetch_request->mails, &mail, 1);
 
-	if (mbox->to_pending_fetch_send == NULL) {
+	if (mbox->to_pending_fetch_send == NULL &&
+	    array_count(&mbox->pending_fetch_request->mails) >
+	    			mbox->box.storage->set->mail_prefetch_count) {
+		/* we're now prefetching the maximum number of mails. this
+		   most likely means that we need to flush out the command now
+		   before sending anything else. delay it a little bit though
+		   in case the sending code doesn't actually use
+		   mail_prefetch_count and wants to fetch more.
+
+		   note that we don't want to add this timeout too early,
+		   because we want to optimize the maximum number of messages
+		   placed into a single FETCH. even without timeout the command
+		   gets flushed by imapc_mail_fetch() call. */
 		mbox->to_pending_fetch_send =
 			timeout_add_short(0, imapc_mail_fetch_flush, mbox);
 	}
@@ -397,7 +409,8 @@
 	imapc_command_send(cmd, str_c(mbox->pending_fetch_cmd));
 
 	mbox->pending_fetch_request = NULL;
-	timeout_remove(&mbox->to_pending_fetch_send);
+	if (mbox->to_pending_fetch_send != NULL)
+		timeout_remove(&mbox->to_pending_fetch_send);
 	str_truncate(mbox->pending_fetch_cmd, 0);
 }