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InnoDB stores a 32-bit page number in page headers and in some data structures, such as FIL_ADDR (consisting of a 32-bit page number and a 16-bit byte offset within a page). For better compile-time error detection and to reduce the memory footprint in some data structures, let us use a uint32_t for the page number, instead of ulint (size_t) which can be 64 bits.
149 lines
4.7 KiB
Text
149 lines
4.7 KiB
Text
/*****************************************************************************
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Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
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Copyright (c) 2015, 2020, 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/btr0btr.ic
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The B-tree
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Created 6/2/1994 Heikki Tuuri
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*******************************************************/
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#include "mach0data.h"
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#include "mtr0mtr.h"
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#include "mtr0log.h"
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#include "page0zip.h"
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/**************************************************************//**
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Gets the index id field of a page.
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@return index id */
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UNIV_INLINE
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index_id_t
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btr_page_get_index_id(
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/*==================*/
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const page_t* page) /*!< in: index page */
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{
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return(mach_read_from_8(page + PAGE_HEADER + PAGE_INDEX_ID));
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}
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/** Set PAGE_LEVEL.
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@param[in,out] block buffer block
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@param[in] level page level
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@param[in,out] mtr mini-transaction */
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inline
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void btr_page_set_level(buf_block_t *block, ulint level, mtr_t *mtr)
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{
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ut_ad(level <= BTR_MAX_NODE_LEVEL);
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constexpr uint16_t field= PAGE_HEADER + PAGE_LEVEL;
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byte *b= my_assume_aligned<2>(&block->frame[field]);
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if (mtr->write<2,mtr_t::MAYBE_NOP>(*block, b, level) &&
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UNIV_LIKELY_NULL(block->page.zip.data))
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memcpy_aligned<2>(&block->page.zip.data[field], b, 2);
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}
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/** Set FIL_PAGE_NEXT.
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@param[in,out] block buffer block
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@param[in] next number of successor page
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@param[in,out] mtr mini-transaction */
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inline void btr_page_set_next(buf_block_t *block, ulint next, mtr_t *mtr)
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{
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constexpr uint16_t field= FIL_PAGE_NEXT;
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byte *b= my_assume_aligned<4>(&block->frame[field]);
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if (mtr->write<4,mtr_t::MAYBE_NOP>(*block, b, next) &&
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UNIV_LIKELY_NULL(block->page.zip.data))
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memcpy_aligned<4>(&block->page.zip.data[field], b, 4);
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}
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/** Set FIL_PAGE_PREV.
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@param[in,out] block buffer block
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@param[in] prev number of predecessor page
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@param[in,out] mtr mini-transaction */
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inline void btr_page_set_prev(buf_block_t *block, ulint prev, mtr_t *mtr)
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{
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constexpr uint16_t field= FIL_PAGE_PREV;
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byte *b= my_assume_aligned<4>(&block->frame[field]);
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if (mtr->write<4,mtr_t::MAYBE_NOP>(*block, b, prev) &&
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UNIV_LIKELY_NULL(block->page.zip.data))
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memcpy_aligned<4>(&block->page.zip.data[field], b, 4);
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}
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/**************************************************************//**
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Gets the child node file address in a node pointer.
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NOTE: the offsets array must contain all offsets for the record since
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we read the last field according to offsets and assume that it contains
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the child page number. In other words offsets must have been retrieved
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with rec_get_offsets(n_fields=ULINT_UNDEFINED).
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@return child node address */
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UNIV_INLINE
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uint32_t
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btr_node_ptr_get_child_page_no(
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/*===========================*/
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const rec_t* rec, /*!< in: node pointer record */
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const rec_offs* offsets)/*!< in: array returned by rec_get_offsets() */
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{
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const byte* field;
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ulint len;
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ut_ad(!rec_offs_comp(offsets) || rec_get_node_ptr_flag(rec));
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/* The child address is in the last field */
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field = rec_get_nth_field(rec, offsets,
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rec_offs_n_fields(offsets) - 1, &len);
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ut_ad(len == 4);
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uint32_t page_no = mach_read_from_4(field);
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ut_ad(page_no > 1);
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return(page_no);
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}
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/**************************************************************//**
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Releases the latches on a leaf page and bufferunfixes it. */
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UNIV_INLINE
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void
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btr_leaf_page_release(
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/*==================*/
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buf_block_t* block, /*!< in: buffer block */
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ulint latch_mode, /*!< in: BTR_SEARCH_LEAF or
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BTR_MODIFY_LEAF */
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mtr_t* mtr) /*!< in: mtr */
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{
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ut_ad(latch_mode == BTR_SEARCH_LEAF
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|| latch_mode == BTR_MODIFY_LEAF
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|| latch_mode == BTR_NO_LATCHES);
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ut_ad(!mtr->memo_contains_flagged(block, MTR_MEMO_MODIFY));
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mtr_memo_type_t mode;
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switch (latch_mode) {
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case BTR_SEARCH_LEAF:
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mode = MTR_MEMO_PAGE_S_FIX;
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break;
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case BTR_MODIFY_LEAF:
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mode = MTR_MEMO_PAGE_X_FIX;
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break;
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case BTR_NO_LATCHES:
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mode = MTR_MEMO_BUF_FIX;
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break;
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default:
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ut_a(0);
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}
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mtr->memo_release(block, mode);
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}
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