From 61ffe793a8ae7d108af7473524d8d89edaea432a Mon Sep 17 00:00:00 2001
From: Vladimir Davydov <vdavydov.dev@gmail.com>
Date: Mon, 11 Sep 2017 13:59:40 +0300
Subject: [PATCH] vinyl: fix read iterator restoration to a newer version of
the same key
After the read iterator selects the minimal key across all available
sources, it checks mutable sources for new statements using ->restore()
callback. If there is a new statement in a source, it uses it as the min
key provided it is *strictly* less than the current min key. If they are
equal, the min key isn't changed, but this is wrong, because the new
statement may be newer than the statement selected previously. If we
don't select it, we might end up with stale data in the cache. Fix this.
---
src/box/vy_read_iterator.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/box/vy_read_iterator.c b/src/box/vy_read_iterator.c
index b0b0b6f7b8..cbdf6584a3 100644
--- a/src/box/vy_read_iterator.c
+++ b/src/box/vy_read_iterator.c
@@ -366,7 +366,10 @@ vy_merge_iterator_next_key(struct vy_merge_iterator *itr, struct tuple **ret)
int cmp = min_stmt == NULL ? -1 :
dir * vy_tuple_compare(src->stmt, min_stmt, def);
- if (cmp < 0) {
+ if (cmp > 0)
+ continue;
+
+ if (cmp < 0 || vy_stmt_lsn(src->stmt) > vy_stmt_lsn(min_stmt)) {
itr->front_id++;
if (min_stmt)
tuple_unref(min_stmt);
@@ -374,7 +377,7 @@ vy_merge_iterator_next_key(struct vy_merge_iterator *itr, struct tuple **ret)
tuple_ref(min_stmt);
itr->curr_src = i;
src->front_id = itr->front_id;
- } else if (cmp == 0) {
+ } else {
itr->curr_src = MIN(itr->curr_src, (uint32_t)i);
src->front_id = itr->front_id;
}
--
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