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9bb5d9fe8b
purge_node_t, undo_node_t: Change the type of rec_type and cmpl_info to byte, because this data is being extracted from a single byte. UndoRecApplier: Change type and cmpl_info to be of type byte, and move them next to the 16-bit offset field to minimize alignment bloat. row_purge_parse_undo_rec(): Remove some redundant code. Purge will be started by innodb_ddl_recovery_done(), at which point all necessary subsystems will have been initialized. trx_purge_rec_t::undo_rec: Point to const. Reviewed by: Vladislav Lesin
114 lines
4.7 KiB
C
114 lines
4.7 KiB
C
/*****************************************************************************
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Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
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Copyright (c) 2017, MariaDB Corporation.
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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 Street, Fifth Floor, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/row0undo.h
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Row undo
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Created 1/8/1997 Heikki Tuuri
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*******************************************************/
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#ifndef row0undo_h
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#define row0undo_h
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#include "trx0sys.h"
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#include "btr0types.h"
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#include "btr0pcur.h"
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#include "que0types.h"
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#include "row0types.h"
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/********************************************************************//**
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Creates a row undo node to a query graph.
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@return own: undo node */
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undo_node_t*
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row_undo_node_create(
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/*=================*/
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trx_t* trx, /*!< in: transaction */
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que_thr_t* parent, /*!< in: parent node, i.e., a thr node */
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mem_heap_t* heap); /*!< in: memory heap where created */
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/***********************************************************//**
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Looks for the clustered index record when node has the row reference.
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The pcur in node is used in the search. If found, stores the row to node,
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and stores the position of pcur, and detaches it. The pcur must be closed
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by the caller in any case.
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@return true if found; NOTE the node->pcur must be closed by the
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caller, regardless of the return value */
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bool
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row_undo_search_clust_to_pcur(
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/*==========================*/
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undo_node_t* node) /*!< in/out: row undo node */
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MY_ATTRIBUTE((warn_unused_result));
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/***********************************************************//**
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Undoes a row operation in a table. This is a high-level function used
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in SQL execution graphs.
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@return query thread to run next or NULL */
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que_thr_t*
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row_undo_step(
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/*==========*/
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que_thr_t* thr); /*!< in: query thread */
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/* A single query thread will try to perform the undo for all successive
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versions of a clustered index record, if the transaction has modified it
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several times during the execution which is rolled back. It may happen
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that the task is transferred to another query thread, if the other thread
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is assigned to handle an undo log record in the chain of different versions
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of the record, and the other thread happens to get the x-latch to the
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clustered index record at the right time.
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If a query thread notices that the clustered index record it is looking
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for is missing, or the roll ptr field in the record doed not point to the
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undo log record the thread was assigned to handle, then it gives up the undo
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task for that undo log record, and fetches the next. This situation can occur
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just in the case where the transaction modified the same record several times
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and another thread is currently doing the undo for successive versions of
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that index record. */
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/** Undo node structure */
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struct undo_node_t{
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que_common_t common; /*!< node type: QUE_NODE_UNDO */
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bool is_temp;/*!< whether this is a temporary table */
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trx_t* trx; /*!< trx for which undo is done */
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roll_ptr_t roll_ptr;/*!< roll pointer to undo log record */
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trx_undo_rec_t* undo_rec;/*!< undo log record */
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undo_no_t undo_no;/*!< undo number of the record */
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byte rec_type;/*!< undo log record type: TRX_UNDO_INSERT_REC,
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... */
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trx_id_t new_trx_id; /*!< trx id to restore to clustered index
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record */
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btr_pcur_t pcur; /*!< persistent cursor used in searching the
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clustered index record */
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dict_table_t* table; /*!< table where undo is done */
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ulint cmpl_info;/*!< compiler analysis of an update */
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upd_t* update; /*!< update vector for a clustered index
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record */
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const dtuple_t* ref; /*!< row reference to the next row to handle */
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dtuple_t* row; /*!< a copy (also fields copied to heap) of the
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row to handle */
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row_ext_t* ext; /*!< NULL, or prefixes of the externally
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stored columns of the row */
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dtuple_t* undo_row;/*!< NULL, or the row after undo */
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row_ext_t* undo_ext;/*!< NULL, or prefixes of the externally
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stored columns of undo_row */
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dict_index_t* index; /*!< the next index whose record should be
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handled */
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mem_heap_t* heap; /*!< memory heap used as auxiliary storage for
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row; this must be emptied after undo is tried
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on a row */
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};
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#endif
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