diff options
Diffstat (limited to 'storage/xtradb/include/read0read.ic')
| -rw-r--r-- | storage/xtradb/include/read0read.ic | 41 |
1 files changed, 17 insertions, 24 deletions
diff --git a/storage/xtradb/include/read0read.ic b/storage/xtradb/include/read0read.ic index 5bb5249b591..ebcdb767406 100644 --- a/storage/xtradb/include/read0read.ic +++ b/storage/xtradb/include/read0read.ic @@ -25,6 +25,11 @@ Created 2/16/1997 Heikki Tuuri /*********************************************************************//** Gets the nth trx id in a read view. + +Upstream code stores array of trx_ids in the descending order. Percona Server +keeps it in the ascending order for performance reasons. Let us keep the +semantics. + @return trx id */ UNIV_INLINE trx_id_t @@ -33,13 +38,17 @@ read_view_get_nth_trx_id( const read_view_t* view, /*!< in: read view */ ulint n) /*!< in: position */ { - ut_ad(n < view->n_trx_ids); + ut_ad(n < view->n_descr); - return(*(view->trx_ids + n)); + return(view->descriptors[view->n_descr - 1 - n]); } /*********************************************************************//** -Sets the nth trx id in a read view. */ +Sets the nth trx id in a read view. + +Upstream code stores array of trx_ids in the descending order. Percona Server +keeps it in the ascending order for performance reasons. Let us keep the +semantics. */ UNIV_INLINE void read_view_set_nth_trx_id( @@ -48,9 +57,9 @@ read_view_set_nth_trx_id( ulint n, /*!< in: position */ trx_id_t trx_id) /*!< in: trx id to set */ { - ut_ad(n < view->n_trx_ids); + ut_ad(n < view->n_descr); - *(view->trx_ids + n) = trx_id; + view->descriptors[view->n_descr - 1 - n] = trx_id; } /*********************************************************************//** @@ -63,9 +72,6 @@ read_view_sees_trx_id( const read_view_t* view, /*!< in: read view */ trx_id_t trx_id) /*!< in: trx id */ { - ulint n_ids; - ulint i; - if (trx_id < view->up_limit_id) { return(TRUE); @@ -76,21 +82,8 @@ read_view_sees_trx_id( 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++) { - trx_id_t view_trx_id - = read_view_get_nth_trx_id(view, n_ids - i - 1); - - if (trx_id <= view_trx_id) { - return(trx_id != view_trx_id); - } - } + /* Do a binary search over this view's descriptors array */ - return(TRUE); + return(trx_find_descriptor(view->descriptors, view->n_descr, + trx_id) == NULL); } |