polardbxengine/storage/innobase/include/trx0purge.ic

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/*****************************************************************************
Copyright (c) 1996, 2018, Oracle and/or its affiliates. All Rights Reserved.
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FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
for more details.
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*****************************************************************************/
/** @file include/trx0purge.ic
Purge old versions
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "trx0undo.h"
/** Calculates the file address of an undo log header when we have the file
address of its history list node.
@return file address of the log */
UNIV_INLINE
fil_addr_t trx_purge_get_log_from_hist(
fil_addr_t node_addr) /*!< in: file address of the history
list node of the log */
{
node_addr.boffset -= TRX_UNDO_HISTORY_NODE;
return (node_addr);
}
/** address of its history list node.
@return true if purge_sys_t::limit <= purge_sys_t::iter */
UNIV_INLINE
bool trx_purge_check_limit(void) {
/* limit is used to track till what point purge element has been
processed and so limit <= iter.
undo_no ordering is enforced only within the same rollback segment.
If a transaction uses multiple rollback segments then we need to
consider the rollback segment space id too. */
return (purge_sys->iter.scn > purge_sys->limit.scn ||
(purge_sys->iter.scn == purge_sys->limit.scn &&
((purge_sys->iter.undo_no >= purge_sys->limit.undo_no) ||
(purge_sys->iter.undo_rseg_space !=
purge_sys->limit.undo_rseg_space))));
}