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4dc30f3c17
This will allow us to reduce critical section protected by trx_sys.mutex: - no need to maintain global m_free list - eliminate if (trx->read_view == NULL) condition. On x86_64 sizeof(Readview) is 144 mostly due to padding, sizeof(trx_t) with ReadView is 1200. Also don't close ReadView for read-write transactions, just mark it closed similarly to read-only. Clean-up: removed n_prepared_recovered_trx and n_prepared_trx, which accidentally re-appeared after some rebase.
81 lines
2.2 KiB
C++
81 lines
2.2 KiB
C++
/*****************************************************************************
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Copyright (c) 1997, 2013, Oracle and/or its affiliates. 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 Street, Suite 500, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/read0read.h
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Cursor read
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Created 2/16/1997 Heikki Tuuri
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*******************************************************/
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#ifndef read0read_h
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#define read0read_h
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#include "univ.i"
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#include "read0types.h"
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/** The MVCC read view manager */
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class MVCC
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{
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/** Active views. */
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UT_LIST_BASE_NODE_T(ReadView) m_views;
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/** Validates a read view list. */
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bool validate() const;
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public:
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MVCC() { UT_LIST_INIT(m_views, &ReadView::m_view_list); }
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~MVCC() { ut_ad(UT_LIST_GET_LEN(m_views) == 0); }
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/**
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Allocate and create a view.
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@param trx transaction creating the view
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*/
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void view_open(trx_t *trx);
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/**
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Close a view created by the above function.
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@param view view allocated by view_open.
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*/
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void view_close(ReadView &view)
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{
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view.close();
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view.set_registered(false);
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UT_LIST_REMOVE(m_views, &view);
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ut_ad(validate());
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}
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/**
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Clones the oldest view and stores it in view. No need to
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call view_close(). The caller owns the view that is passed in.
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This function is called by Purge to create it view.
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@param view Preallocated view, owned by the caller
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*/
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void clone_oldest_view(ReadView *view);
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/** @return the number of active views */
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size_t size() const;
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};
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#endif /* read0read_h */
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