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89 lines
2.6 KiB
Text
89 lines
2.6 KiB
Text
/*****************************************************************************
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Copyright (c) 1997, 2009, Innobase Oy. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/read0read.ic
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Cursor read
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Created 2/16/1997 Heikki Tuuri
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*******************************************************/
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/*********************************************************************//**
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Gets the nth trx id in a read view.
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Upstream code stores array of trx_ids in the descending order. Percona Server
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keeps it in the ascending order for performance reasons. Let us keep the
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semantics.
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@return trx id */
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UNIV_INLINE
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trx_id_t
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read_view_get_nth_trx_id(
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/*=====================*/
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const read_view_t* view, /*!< in: read view */
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ulint n) /*!< in: position */
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{
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ut_ad(n < view->n_descr);
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return(view->descriptors[view->n_descr - 1 - n]);
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}
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/*********************************************************************//**
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Sets the nth trx id in a read view.
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Upstream code stores array of trx_ids in the descending order. Percona Server
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keeps it in the ascending order for performance reasons. Let us keep the
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semantics. */
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UNIV_INLINE
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void
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read_view_set_nth_trx_id(
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/*=====================*/
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read_view_t* view, /*!< in: read view */
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ulint n, /*!< in: position */
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trx_id_t trx_id) /*!< in: trx id to set */
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{
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ut_ad(n < view->n_descr);
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view->descriptors[view->n_descr - 1 - n] = trx_id;
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}
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/*********************************************************************//**
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Checks if a read view sees the specified transaction.
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@return TRUE if sees */
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UNIV_INLINE
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ibool
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read_view_sees_trx_id(
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/*==================*/
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const read_view_t* view, /*!< in: read view */
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trx_id_t trx_id) /*!< in: trx id */
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{
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if (trx_id < view->up_limit_id) {
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return(TRUE);
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}
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if (trx_id >= view->low_limit_id) {
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return(FALSE);
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}
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/* Do a binary search over this view's descriptors array */
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return(trx_find_descriptor(view->descriptors, view->n_descr,
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trx_id) == NULL);
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}
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