summaryrefslogtreecommitdiff
path: root/innobase/include/read0read.ic
diff options
context:
space:
mode:
Diffstat (limited to 'innobase/include/read0read.ic')
-rw-r--r--innobase/include/read0read.ic85
1 files changed, 85 insertions, 0 deletions
diff --git a/innobase/include/read0read.ic b/innobase/include/read0read.ic
new file mode 100644
index 00000000000..03d84ee0c51
--- /dev/null
+++ b/innobase/include/read0read.ic
@@ -0,0 +1,85 @@
+/******************************************************
+Cursor read
+
+(c) 1997 Innobase Oy
+
+Created 2/16/1997 Heikki Tuuri
+*******************************************************/
+
+/*************************************************************************
+Gets the nth trx id in a read view. */
+UNIV_INLINE
+dulint
+read_view_get_nth_trx_id(
+/*=====================*/
+ /* out: trx id */
+ read_view_t* view, /* in: read view */
+ ulint n) /* in: position */
+{
+ ut_ad(n < view->n_trx_ids);
+
+ return(*(view->trx_ids + n));
+}
+
+/*************************************************************************
+Sets the nth trx id in a read view. */
+UNIV_INLINE
+void
+read_view_set_nth_trx_id(
+/*=====================*/
+ read_view_t* view, /* in: read view */
+ ulint n, /* in: position */
+ dulint trx_id) /* in: trx id to set */
+{
+ ut_ad(n < view->n_trx_ids);
+
+ *(view->trx_ids + n) = trx_id;
+}
+
+/*************************************************************************
+Checks if a read view sees the specified transaction. */
+UNIV_INLINE
+ibool
+read_view_sees_trx_id(
+/*==================*/
+ /* out: TRUE if sees */
+ read_view_t* view, /* in: read view */
+ dulint trx_id) /* in: trx id */
+{
+ ulint n_ids;
+ int cmp;
+ ulint i;
+
+ if (ut_dulint_cmp(trx_id, view->up_limit_id) < 0) {
+
+ return(TRUE);
+ }
+
+ if (ut_dulint_cmp(trx_id, view->low_limit_id) >= 0) {
+
+ return(FALSE);
+ }
+
+ /* We go through the trx ids in the array smallest first: this order
+ may save CPU time, because if there was a very long running
+ transaction in the trx id array, its trx id is looked at first, and
+ the first two comparisons may well decide the visibility of trx_id. */
+
+ n_ids = view->n_trx_ids;
+
+ for (i = 0; i < n_ids; i++) {
+
+ cmp = ut_dulint_cmp(trx_id,
+ read_view_get_nth_trx_id(view, n_ids - i - 1));
+ if (0 == cmp) {
+
+ return(FALSE);
+
+ } else if (cmp < 0) {
+
+ return(TRUE);
+ }
+ }
+
+ return(TRUE);
+}