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btr0cur.c:

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Remove long latch hold which happened if we scanned long an index without finding any record visible to the current consistent read


innobase/btr/btr0cur.c:
  Remove long latch hold which happened if we scanned long an index without finding any record visible to the current consistent read
This commit is contained in:
unknown 2002-09-08 03:01:53 +03:00
parent 94bbbc7f36
commit fab80610af
1 changed files with 25 additions and 0 deletions
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25
innobase/btr/btr0cur.c
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@ -302,6 +302,9 @@ btr_cur_search_to_nth_level(
rw_lock_s_unlock(&btr_search_latch);
}
/* Store the position of the tree latch we push to mtr so that we
know how to release it when we have latched leaf node(s) */
savepoint = mtr_set_savepoint(mtr);
tree = index->tree;
@ -506,12 +509,18 @@ btr_cur_open_at_index_side(
ulint root_height;
rec_t* node_ptr;
ulint estimate;
ulint savepoint;
estimate = latch_mode & BTR_ESTIMATE;
latch_mode = latch_mode & ~BTR_ESTIMATE;
tree = index->tree;
/* Store the position of the tree latch we push to mtr so that we
know how to release it when we have latched the leaf node */
savepoint = mtr_set_savepoint(mtr);
if (latch_mode == BTR_MODIFY_TREE) {
mtr_x_lock(dict_tree_get_lock(tree), mtr);
} else {
@ -544,6 +553,22 @@ btr_cur_open_at_index_side(
if (height == 0) {
btr_cur_latch_leaves(tree, page, space, page_no,
latch_mode, cursor, mtr);
/* In versions <= 3.23.52 we had forgotten to
release the tree latch here. If in an index scan
we had to scan far to find a record visible to the
current transaction, that could starve others
waiting for the tree latch. */
if ((latch_mode != BTR_MODIFY_TREE)
&& (latch_mode != BTR_CONT_MODIFY_TREE)) {
/* Release the tree s-latch */
mtr_release_s_latch_at_savepoint(
mtr, savepoint,
dict_tree_get_lock(tree));
}
}
if (from_left) {