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/*****************************************************************************
Copyright (c) 1997, 2009, Innobase Oy. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file include/read0read.ic
Cursor read
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
read_view_get_nth_trx_id(
/*=====================*/
const read_view_t* view, /*!< in: read view */
ulint n) /*!< in: position */
{
ut_ad(n < view->n_descr);
return(view->descriptors[view->n_descr - 1 - n]);
}
/*********************************************************************//**
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(
/*=====================*/
read_view_t* view, /*!< in: read view */
ulint n, /*!< in: position */
trx_id_t trx_id) /*!< in: trx id to set */
{
ut_ad(n < view->n_descr);
view->descriptors[view->n_descr - 1 - n] = trx_id;
}
/*********************************************************************//**
Checks if a read view sees the specified transaction.
@return TRUE if sees */
UNIV_INLINE
ibool
read_view_sees_trx_id(
/*==================*/
const read_view_t* view, /*!< in: read view */
trx_id_t trx_id) /*!< in: trx id */
{
if (trx_id < view->up_limit_id) {
return(TRUE);
}
if (trx_id >= view->low_limit_id) {
return(FALSE);
}
/* Do a binary search over this view's descriptors array */
return(trx_find_descriptor(view->descriptors, view->n_descr,
trx_id) == NULL);
}
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