diff --git a/src/box/vy_cache.c b/src/box/vy_cache.c
index b27e04a58017f01663ca13f28562faeef9b44b8f..825bfd3b6c7f300772f6fefaec7963acd0f2c7fd 100644
--- a/src/box/vy_cache.c
+++ b/src/box/vy_cache.c
@@ -581,20 +581,22 @@ vy_cache_iterator_is_end_stop(struct vy_cache_iterator *itr,
* Make one tree's iterator step from the current position.
* Direction of the step depends on the iterator type.
* @param itr Iterator to make step.
- * @param[out] ret Result tuple.
*
- * @retval Must a merge_iterator stop on @a ret?
- * The function is implicitly used by merge_iterator_next_key and
- * return value is used to determine if the merge_iterator can
- * return @a ret to a read_iterator immediately, without lookups
- * in mems and runs. It is possible, when @a ret is a part of
+ * @retval Must a read iterator stop on the cached statement?
+ * The function is implicitly used by vy_read_iterator_next and
+ * return value is used to determine if the read iterator can
+ * return the cached statement without lookups in mems and runs.
+ * It is possible when the cached statement is a part of a
* continuous cached tuples chain. In such a case mems or runs can
* not contain more suitable tuples.
*/
static inline bool
-vy_cache_iterator_step(struct vy_cache_iterator *itr, struct tuple **ret)
+vy_cache_iterator_step(struct vy_cache_iterator *itr)
{
- *ret = NULL;
+ if (itr->curr_stmt != NULL) {
+ tuple_unref(itr->curr_stmt);
+ itr->curr_stmt = NULL;
+ }
struct vy_cache_tree *tree = &itr->cache->cache_tree;
struct vy_cache_entry *prev_entry =
*vy_cache_tree_iterator_get_elem(tree, &itr->curr_pos);
@@ -611,7 +613,8 @@ vy_cache_iterator_step(struct vy_cache_iterator *itr, struct tuple **ret)
vy_stmt_compare(itr->key, entry->stmt, itr->cache->cmp_def)) {
return vy_cache_iterator_is_end_stop(itr, prev_entry);
}
- *ret = entry->stmt;
+ itr->curr_stmt = entry->stmt;
+ tuple_ref(itr->curr_stmt);
return vy_cache_iterator_is_stop(itr, entry);
}
@@ -629,7 +632,7 @@ vy_cache_iterator_skip_to_read_view(struct vy_cache_iterator *itr, bool *stop)
* but there could be older tuples in runs.
*/
*stop = false;
- vy_cache_iterator_step(itr, &itr->curr_stmt);
+ vy_cache_iterator_step(itr);
}
}
@@ -637,15 +640,21 @@ vy_cache_iterator_skip_to_read_view(struct vy_cache_iterator *itr, bool *stop)
* Position the iterator to the first cache entry satisfying
* the iterator search criteria and following the given key
* (pass NULL to start iteration).
+ *
+ * Like vy_cache_iterator_step(), this functions returns true
+ * if the cached statement is a part of a continuous tuple chain
+ * and hence the caller doesn't need to scan mems and runs.
*/
-static void
+static bool
vy_cache_iterator_seek(struct vy_cache_iterator *itr,
- const struct tuple *last_key,
- struct vy_cache_entry **ret)
+ const struct tuple *last_key)
{
struct vy_cache_tree *tree = &itr->cache->cache_tree;
- *ret = NULL;
+ if (itr->curr_stmt != NULL) {
+ tuple_unref(itr->curr_stmt);
+ itr->curr_stmt = NULL;
+ }
itr->cache->stat.lookup++;
const struct tuple *key = itr->key;
@@ -673,7 +682,7 @@ vy_cache_iterator_seek(struct vy_cache_iterator *itr,
if (iterator_type == ITER_LT || iterator_type == ITER_LE)
vy_cache_tree_iterator_prev(tree, &itr->curr_pos);
if (vy_cache_tree_iterator_is_invalid(&itr->curr_pos))
- return;
+ return false;
struct vy_cache_entry *entry;
entry = *vy_cache_tree_iterator_get_elem(tree, &itr->curr_pos);
@@ -682,39 +691,33 @@ vy_cache_iterator_seek(struct vy_cache_iterator *itr,
((last_key == NULL && !exact) ||
(last_key != NULL && vy_stmt_compare(itr->key, entry->stmt,
itr->cache->cmp_def) != 0)))
- return;
+ return false;
- *ret = entry;
+ itr->curr_stmt = entry->stmt;
+ tuple_ref(itr->curr_stmt);
+ return vy_cache_iterator_is_stop(itr, entry);
}
NODISCARD int
vy_cache_iterator_next(struct vy_cache_iterator *itr,
struct vy_history *history, bool *stop)
{
- *stop = false;
vy_history_cleanup(history);
if (!itr->search_started) {
assert(itr->curr_stmt == NULL);
itr->search_started = true;
itr->version = itr->cache->version;
- struct vy_cache_entry *entry;
- vy_cache_iterator_seek(itr, NULL, &entry);
- if (entry == NULL)
- return 0;
- itr->curr_stmt = entry->stmt;
- *stop = vy_cache_iterator_is_stop(itr, entry);
+ *stop = vy_cache_iterator_seek(itr, NULL);
} else {
assert(itr->version == itr->cache->version);
if (itr->curr_stmt == NULL)
return 0;
- tuple_unref(itr->curr_stmt);
- *stop = vy_cache_iterator_step(itr, &itr->curr_stmt);
+ *stop = vy_cache_iterator_step(itr);
}
vy_cache_iterator_skip_to_read_view(itr, stop);
if (itr->curr_stmt != NULL) {
- tuple_ref(itr->curr_stmt);
vy_stmt_counter_acct_tuple(&itr->cache->stat.get,
itr->curr_stmt);
return vy_history_append_stmt(history, itr->curr_stmt);
@@ -740,25 +743,14 @@ vy_cache_iterator_skip(struct vy_cache_iterator *itr,
itr->cache->cmp_def) > 0))
return 0;
- *stop = false;
vy_history_cleanup(history);
itr->search_started = true;
itr->version = itr->cache->version;
- if (itr->curr_stmt != NULL)
- tuple_unref(itr->curr_stmt);
- itr->curr_stmt = NULL;
-
- struct vy_cache_entry *entry;
- vy_cache_iterator_seek(itr, last_stmt, &entry);
- if (entry != NULL) {
- *stop = vy_cache_iterator_is_stop(itr, entry);
- itr->curr_stmt = entry->stmt;
- }
-
+ *stop = vy_cache_iterator_seek(itr, last_stmt);
vy_cache_iterator_skip_to_read_view(itr, stop);
+
if (itr->curr_stmt != NULL) {
- tuple_ref(itr->curr_stmt);
vy_stmt_counter_acct_tuple(&itr->cache->stat.get,
itr->curr_stmt);
return vy_history_append_stmt(history, itr->curr_stmt);
@@ -776,9 +768,6 @@ vy_cache_iterator_restore(struct vy_cache_iterator *itr,
itr->version = itr->cache->version;
struct tuple *prev_stmt = itr->curr_stmt;
- if (prev_stmt != NULL)
- tuple_unref(prev_stmt);
-
if ((prev_stmt == NULL && itr->iterator_type == ITER_EQ) ||
(prev_stmt != NULL &&
prev_stmt != vy_cache_iterator_curr_stmt(itr))) {
@@ -787,13 +776,7 @@ vy_cache_iterator_restore(struct vy_cache_iterator *itr,
* In either case the best we can do is restart the
* search.
*/
- struct vy_cache_entry *entry;
- vy_cache_iterator_seek(itr, last_stmt, &entry);
- itr->curr_stmt = NULL;
- if (entry != NULL) {
- *stop = vy_cache_iterator_is_stop(itr, entry);
- itr->curr_stmt = entry->stmt;
- }
+ *stop = vy_cache_iterator_seek(itr, last_stmt);
vy_cache_iterator_skip_to_read_view(itr, stop);
} else {
/*
@@ -830,7 +813,10 @@ vy_cache_iterator_restore(struct vy_cache_iterator *itr,
break;
if (vy_stmt_lsn(entry->stmt) <= (**itr->read_view).vlsn) {
itr->curr_pos = pos;
+ if (itr->curr_stmt != NULL)
+ tuple_unref(itr->curr_stmt);
itr->curr_stmt = entry->stmt;
+ tuple_ref(itr->curr_stmt);
*stop = vy_cache_iterator_is_stop(itr, entry);
}
if (cmp == 0)
@@ -840,7 +826,6 @@ vy_cache_iterator_restore(struct vy_cache_iterator *itr,
vy_history_cleanup(history);
if (itr->curr_stmt != NULL) {
- tuple_ref(itr->curr_stmt);
vy_stmt_counter_acct_tuple(&itr->cache->stat.get,
itr->curr_stmt);
if (vy_history_append_stmt(history, itr->curr_stmt) != 0)