[commit] master: knock out ReNew if there are no dummies

[Oswald B. <os...@us...>]

commit 2f4b71c56e3e6caa76a649018681704628405108
Author: Oswald Buddenhagen <os...@us...>
Date:   Fri Feb 18 17:45:01 2022 +0100

    knock out ReNew if there are no dummies
    
    the operation requires loading the target side, which makes it somewhat
    expensive in otherwise unidirectional syncs.
    
    one could also knock out Flags and Delete if there are no living pairs,
    but that wouldn't actually save much.

 src/sync.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/sync.c b/src/sync.c
index ad8f44db..1e228895 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -680,14 +680,23 @@ box_opened2( sync_vars_t *svars, int t )
 	if (!lock_state( svars ))
 		goto bail;
 
+	int any_dummies[2] = { 0, 0 };
 	int any_purges[2] = { 0, 0 };
 	int any_upgrades[2] = { 0, 0 };
 	int any_new[2] = { 0, 0 };
 	int any_tuids[2] = { 0, 0 };
-	if (svars->replayed) {
+	if (svars->replayed || ((chan->ops[F] | chan->ops[N]) & OP_RENEW)) {
 		for (srec = svars->srecs; srec; srec = srec->next) {
 			if (srec->status & S_DEAD)
 				continue;
+			if (srec->status & S_DUMMY(F))
+				any_dummies[F]++;
+			else if (srec->status & S_DUMMY(N))
+				any_dummies[N]++;
+			else if (srec->status & S_SKIPPED)
+				any_dummies[!srec->uid[F] ? F : N]++;
+			if (!svars->replayed)
+				continue;
 			if (srec->status & S_PURGE) {
 				any_purges[srec->uid[F] ? F : N]++;
 			} else if (srec->status & S_PENDING) {
@@ -721,6 +730,10 @@ box_opened2( sync_vars_t *svars, int t )
 			if (chan->ops[t] & OP_FLAGS)
 				opts[t^1] |= OPEN_FLAGS;
 		}
+		if (!any_dummies[t] && (chan->ops[t] & OP_RENEW)) {
+			chan->ops[t] &= ~OP_RENEW;
+			debug( "no %s dummies; masking ReNew\n", str_fn[t] );
+		}
 		if ((chan->ops[t] & (OP_NEW | OP_RENEW)) || any_new[t] || any_upgrades[t]) {
 			opts[t] |= OPEN_APPEND;
 			if ((chan->ops[t] & OP_NEW) || any_new[t]) {