diff options
Diffstat (limited to 'storage/innobase/include/ibuf0ibuf.h')
| -rw-r--r-- | storage/innobase/include/ibuf0ibuf.h | 457 |
1 files changed, 38 insertions, 419 deletions
diff --git a/storage/innobase/include/ibuf0ibuf.h b/storage/innobase/include/ibuf0ibuf.h index c246b2ef..d1ff331f 100644 --- a/storage/innobase/include/ibuf0ibuf.h +++ b/storage/innobase/include/ibuf0ibuf.h @@ -1,7 +1,6 @@ /***************************************************************************** -Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved. -Copyright (c) 2016, 2022, MariaDB Corporation. +Copyright (c) 2023, MariaDB Corporation. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software @@ -17,420 +16,40 @@ this program; if not, write to the Free Software Foundation, Inc., *****************************************************************************/ -/**************************************************//** -@file include/ibuf0ibuf.h -Insert buffer - -Created 7/19/1997 Heikki Tuuri -*******************************************************/ - -#ifndef ibuf0ibuf_h -#define ibuf0ibuf_h - -#include "mtr0mtr.h" -#include "dict0mem.h" -#include "fsp0fsp.h" - -/** Default value for maximum on-disk size of change buffer in terms -of percentage of the buffer pool. */ -#define CHANGE_BUFFER_DEFAULT_SIZE (25) - -/* Possible operations buffered in the insert/whatever buffer. See -ibuf_insert(). DO NOT CHANGE THE VALUES OF THESE, THEY ARE STORED ON DISK. */ -typedef enum { - IBUF_OP_INSERT = 0, - IBUF_OP_DELETE_MARK = 1, - IBUF_OP_DELETE = 2, - - /* Number of different operation types. */ - IBUF_OP_COUNT = 3 -} ibuf_op_t; - -/** Combinations of operations that can be buffered. -@see innodb_change_buffering_names */ -enum ibuf_use_t { - IBUF_USE_NONE = 0, - IBUF_USE_INSERT, /* insert */ - IBUF_USE_DELETE_MARK, /* delete */ - IBUF_USE_INSERT_DELETE_MARK, /* insert+delete */ - IBUF_USE_DELETE, /* delete+purge */ - IBUF_USE_ALL /* insert+delete+purge */ -}; - -/** Operations that can currently be buffered. */ -extern ulong innodb_change_buffering; - -/** Insert buffer struct */ -struct ibuf_t{ - Atomic_relaxed<ulint> size; /*!< current size of the ibuf index - tree, in pages */ - Atomic_relaxed<ulint> max_size; /*!< recommended maximum size of the - ibuf index tree, in pages */ - ulint seg_size; /*!< allocated pages of the file - segment containing ibuf header and - tree */ - bool empty; /*!< Protected by the page - latch of the root page of the - insert buffer tree - (FSP_IBUF_TREE_ROOT_PAGE_NO). true - if and only if the insert - buffer tree is empty. */ - ulint free_list_len; /*!< length of the free list */ - ulint height; /*!< tree height */ - dict_index_t* index; /*!< insert buffer index */ - - /** number of pages merged */ - Atomic_counter<ulint> n_merges; - Atomic_counter<ulint> n_merged_ops[IBUF_OP_COUNT]; - /*!< number of operations of each type - merged to index pages */ - Atomic_counter<ulint> n_discarded_ops[IBUF_OP_COUNT]; - /*!< number of operations of each type - discarded without merging due to the - tablespace being deleted or the - index being dropped */ -}; - -/** The insert buffer control structure */ -extern ibuf_t ibuf; - -/* The purpose of the insert buffer is to reduce random disk access. -When we wish to insert a record into a non-unique secondary index and -the B-tree leaf page where the record belongs to is not in the buffer -pool, we insert the record into the insert buffer B-tree, indexed by -(space_id, page_no). When the page is eventually read into the buffer -pool, we look up the insert buffer B-tree for any modifications to the -page, and apply these upon the completion of the read operation. This -is called the insert buffer merge. */ - -/* The insert buffer merge must always succeed. To guarantee this, -the insert buffer subsystem keeps track of the free space in pages for -which it can buffer operations. Two bits per page in the insert -buffer bitmap indicate the available space in coarse increments. The -free bits in the insert buffer bitmap must never exceed the free space -on a page. It is safe to decrement or reset the bits in the bitmap in -a mini-transaction that is committed before the mini-transaction that -affects the free space. It is unsafe to increment the bits in a -separately committed mini-transaction, because in crash recovery, the -free bits could momentarily be set too high. */ - -/******************************************************************//** -Creates the insert buffer data structure at a database startup. -@return DB_SUCCESS or failure */ -dberr_t -ibuf_init_at_db_start(void); -/*=======================*/ -/*********************************************************************//** -Updates the max_size value for ibuf. */ -void -ibuf_max_size_update( -/*=================*/ - ulint new_val); /*!< in: new value in terms of - percentage of the buffer pool size */ -/*********************************************************************//** -Reads the biggest tablespace id from the high end of the insert buffer -tree and updates the counter in fil_system. */ -void -ibuf_update_max_tablespace_id(void); -/*===============================*/ -/***************************************************************//** -Starts an insert buffer mini-transaction. */ -UNIV_INLINE -void -ibuf_mtr_start( -/*===========*/ - mtr_t* mtr) /*!< out: mini-transaction */ - MY_ATTRIBUTE((nonnull)); -/***************************************************************//** -Commits an insert buffer mini-transaction. */ -UNIV_INLINE -void -ibuf_mtr_commit( -/*============*/ - mtr_t* mtr) /*!< in/out: mini-transaction */ - MY_ATTRIBUTE((nonnull)); -/************************************************************************//** -Resets the free bits of the page in the ibuf bitmap. This is done in a -separate mini-transaction, hence this operation does not restrict -further work to only ibuf bitmap operations, which would result if the -latch to the bitmap page were kept. NOTE: The free bits in the insert -buffer bitmap must never exceed the free space on a page. It is safe -to decrement or reset the bits in the bitmap in a mini-transaction -that is committed before the mini-transaction that affects the free -space. */ -void -ibuf_reset_free_bits( -/*=================*/ - buf_block_t* block); /*!< in: index page; free bits are set to 0 - if the index is a non-clustered - non-unique, and page level is 0 */ -/************************************************************************//** -Updates the free bits of an uncompressed page in the ibuf bitmap if -there is not enough free on the page any more. This is done in a -separate mini-transaction, hence this operation does not restrict -further work to only ibuf bitmap operations, which would result if the -latch to the bitmap page were kept. NOTE: The free bits in the insert -buffer bitmap must never exceed the free space on a page. It is -unsafe to increment the bits in a separately committed -mini-transaction, because in crash recovery, the free bits could -momentarily be set too high. It is only safe to use this function for -decrementing the free bits. Should more free space become available, -we must not update the free bits here, because that would break crash -recovery. */ -UNIV_INLINE -void -ibuf_update_free_bits_if_full( -/*==========================*/ - buf_block_t* block, /*!< in: index page to which we have added new - records; the free bits are updated if the - index is non-clustered and non-unique and - the page level is 0, and the page becomes - fuller */ - ulint max_ins_size,/*!< in: value of maximum insert size with - reorganize before the latest operation - performed to the page */ - ulint increase);/*!< in: upper limit for the additional space - used in the latest operation, if known, or - ULINT_UNDEFINED */ -/**********************************************************************//** -Updates the free bits for an uncompressed page to reflect the present -state. Does this in the mtr given, which means that the latching -order rules virtually prevent any further operations for this OS -thread until mtr is committed. NOTE: The free bits in the insert -buffer bitmap must never exceed the free space on a page. It is safe -to set the free bits in the same mini-transaction that updated the -page. */ -void -ibuf_update_free_bits_low( -/*======================*/ - const buf_block_t* block, /*!< in: index page */ - ulint max_ins_size, /*!< in: value of - maximum insert size - with reorganize before - the latest operation - performed to the page */ - mtr_t* mtr); /*!< in/out: mtr */ -/**********************************************************************//** -Updates the free bits for a compressed page to reflect the present -state. Does this in the mtr given, which means that the latching -order rules virtually prevent any further operations for this OS -thread until mtr is committed. NOTE: The free bits in the insert -buffer bitmap must never exceed the free space on a page. It is safe -to set the free bits in the same mini-transaction that updated the -page. */ -void -ibuf_update_free_bits_zip( -/*======================*/ - buf_block_t* block, /*!< in/out: index page */ - mtr_t* mtr); /*!< in/out: mtr */ -/**********************************************************************//** -Updates the free bits for the two pages to reflect the present state. -Does this in the mtr given, which means that the latching order rules -virtually prevent any further operations until mtr is committed. -NOTE: The free bits in the insert buffer bitmap must never exceed the -free space on a page. It is safe to set the free bits in the same -mini-transaction that updated the pages. */ -void -ibuf_update_free_bits_for_two_pages_low( -/*====================================*/ - buf_block_t* block1, /*!< in: index page */ - buf_block_t* block2, /*!< in: index page */ - mtr_t* mtr); /*!< in: mtr */ -/**********************************************************************//** -A basic partial test if an insert to the insert buffer could be possible and -recommended. */ -UNIV_INLINE -ibool -ibuf_should_try( -/*============*/ - dict_index_t* index, /*!< in: index where to insert */ - ulint ignore_sec_unique); /*!< in: if != 0, we should - ignore UNIQUE constraint on - a secondary index when we - decide */ -/******************************************************************//** -Returns TRUE if the current OS thread is performing an insert buffer -routine. - -For instance, a read-ahead of non-ibuf pages is forbidden by threads -that are executing an insert buffer routine. -@return TRUE if inside an insert buffer routine */ -UNIV_INLINE -ibool -ibuf_inside( -/*========*/ - const mtr_t* mtr) /*!< in: mini-transaction */ - MY_ATTRIBUTE((warn_unused_result)); - -/** Checks if a page address is an ibuf bitmap page (level 3 page) address. -@param[in] page_id page id -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@return TRUE if a bitmap page */ -inline bool ibuf_bitmap_page(const page_id_t page_id, ulint zip_size) -{ - ut_ad(ut_is_2pow(zip_size)); - ulint size = zip_size ? zip_size : srv_page_size; - return (page_id.page_no() & (size - 1)) == FSP_IBUF_BITMAP_OFFSET; -} - -/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages. -Must not be called when recv_no_ibuf_operations==true. -@param[in] page_id page id -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@param[in] x_latch FALSE if relaxed check (avoid latching the -bitmap page) -@param[in,out] mtr mtr which will contain an x-latch to the -bitmap page if the page is not one of the fixed address ibuf pages, or NULL, -in which case a new transaction is created. -@return true if level 2 or level 3 page */ -bool -ibuf_page_low( - const page_id_t page_id, - ulint zip_size, -#ifdef UNIV_DEBUG - bool x_latch, -#endif /* UNIV_DEBUG */ - mtr_t* mtr) - MY_ATTRIBUTE((warn_unused_result)); - -#ifdef UNIV_DEBUG -/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages. -Must not be called when recv_no_ibuf_operations==true. -@param[in] page_id tablespace/page identifier -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@param[in,out] mtr mini-transaction or NULL -@return TRUE if level 2 or level 3 page */ -# define ibuf_page(page_id, zip_size, mtr) \ - ibuf_page_low(page_id, zip_size, true, mtr) - -#else /* UNIV_DEBUG */ - -/** Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages. -Must not be called when recv_no_ibuf_operations==true. -@param[in] page_id tablespace/page identifier -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@param[in,out] mtr mini-transaction or NULL -@return TRUE if level 2 or level 3 page */ -# define ibuf_page(page_id, zip_size, mtr) \ - ibuf_page_low(page_id, zip_size, mtr) - -#endif /* UNIV_DEBUG */ -/***********************************************************************//** -Frees excess pages from the ibuf free list. This function is called when an OS -thread calls fsp services to allocate a new file segment, or a new page to a -file segment, and the thread did not own the fsp latch before this call. */ -void -ibuf_free_excess_pages(void); -/*========================*/ - -/** Buffer an operation in the change buffer, instead of applying it -directly to the file page, if this is possible. Does not do it if the index -is clustered or unique. -@param[in] op operation type -@param[in] entry index entry to insert -@param[in,out] index index where to insert -@param[in] page_id page id where to insert -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@param[in,out] thr query thread -@return true if success */ -bool -ibuf_insert( - ibuf_op_t op, - const dtuple_t* entry, - dict_index_t* index, - const page_id_t page_id, - ulint zip_size, - que_thr_t* thr); - -/** Check whether buffered changes exist for a page. -@param[in] id page identifier -@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@return whether buffered changes exist */ -bool ibuf_page_exists(const page_id_t id, ulint zip_size); - -/** When an index page is read from a disk to the buffer pool, this function -applies any buffered operations to the page and deletes the entries from the -insert buffer. If the page is not read, but created in the buffer pool, this -function deletes its buffered entries from the insert buffer; there can -exist entries for such a page if the page belonged to an index which -subsequently was dropped. -@param block X-latched page to try to apply changes to, or NULL to discard -@param page_id page identifier -@param zip_size ROW_FORMAT=COMPRESSED page size, or 0 -@return error code */ -dberr_t ibuf_merge_or_delete_for_page(buf_block_t *block, - const page_id_t page_id, - ulint zip_size); - -/** Delete all change buffer entries for a tablespace, -in DISCARD TABLESPACE, IMPORT TABLESPACE, or read-ahead. -@param[in] space missing or to-be-discarded tablespace */ -void ibuf_delete_for_discarded_space(uint32_t space); - -/** Contract the change buffer by reading pages to the buffer pool. -@return a lower limit for the combined size in bytes of entries which -will be merged from ibuf trees to the pages read -@retval 0 if ibuf.empty */ -ulint ibuf_contract(); - -/** Contracts insert buffer trees by reading pages referring to space_id -to the buffer pool. -@returns number of pages merged.*/ -ulint -ibuf_merge_space( -/*=============*/ - ulint space); /*!< in: space id */ - -/******************************************************************//** -Looks if the insert buffer is empty. -@return true if empty */ -bool -ibuf_is_empty(void); -/*===============*/ -/******************************************************************//** -Prints info of ibuf. */ -void -ibuf_print( -/*=======*/ - FILE* file); /*!< in: file where to print */ -/******************************************************************** -Read the first two bytes from a record's fourth field (counter field in new -records; something else in older records). -@return "counter" field, or ULINT_UNDEFINED if for some reason it can't be read */ -ulint -ibuf_rec_get_counter( -/*=================*/ - const rec_t* rec); /*!< in: ibuf record */ -/******************************************************************//** -Closes insert buffer and frees the data structures. */ -void -ibuf_close(void); -/*============*/ - -/** Check the insert buffer bitmaps on IMPORT TABLESPACE. -@param[in] trx transaction -@param[in,out] space tablespace being imported -@return DB_SUCCESS or error code */ -dberr_t ibuf_check_bitmap_on_import(const trx_t* trx, fil_space_t* space) - MY_ATTRIBUTE((nonnull, warn_unused_result)); - -/** Update free bits and buffered bits for bulk loaded page. -@param block secondary index leaf page -@param mtr mini-transaction -@param reset whether the page is full */ -void ibuf_set_bitmap_for_bulk_load(buf_block_t *block, mtr_t *mtr, bool reset); - -#define IBUF_HEADER_PAGE_NO FSP_IBUF_HEADER_PAGE_NO -#define IBUF_TREE_ROOT_PAGE_NO FSP_IBUF_TREE_ROOT_PAGE_NO - -/* The ibuf header page currently contains only the file segment header -for the file segment from which the pages for the ibuf tree are allocated */ -#define IBUF_HEADER PAGE_DATA -#define IBUF_TREE_SEG_HEADER 0 /* fseg header for ibuf tree */ - -/* The insert buffer tree itself is always located in space 0. */ -#define IBUF_SPACE_ID static_cast<ulint>(0) - -#include "ibuf0ibuf.inl" - -#endif +#include "db0err.h" + +/* The purpose of the change buffer was to reduce random disk access. +When we wished to +(1) insert a record into a non-unique secondary index, +(2) delete-mark a secondary index record, +(3) delete a secondary index record as part of purge (but not ROLLBACK), +and the B-tree leaf page where the record belongs to is not in the buffer +pool, we inserted a record into the change buffer B-tree, indexed by +the page identifier. When the page was eventually read into the buffer +pool, we looked up the change buffer B-tree for any modifications to the +page, applied these upon the completion of the read operation. This +was called the insert buffer merge. + +There was a hash index of the change buffer B-tree, implemented as the +"change buffer bitmap". Bits in these bitmap pages indicated how full +the page roughly was, and whether any records for the page identifier +exist in the change buffer. The "free" bits had to be updated as part of +operations that modified secondary index leaf pages. + +Because the change buffer has been removed, we will no longer update +any change buffer bitmap pages. Instead, on database startup, we will +check if an upgrade needs to be performed, and apply any buffered +changes if that is the case. Finally, the change buffer will be +transformed to a format that will not be recognized by earlier +versions of MariaDB Server, to prevent downgrades from causing +corruption (due to the removed updates of the bitmap pages) when the +change buffer might be enabled. */ + +/** Check if ibuf_upgrade() is needed as part of server startup. +@return error code +@retval DB_SUCCESS if no upgrade is needed +@retval DB_FAIL if the change buffer is not empty (need ibuf_upgrade()) */ +dberr_t ibuf_upgrade_needed(); + +/** Upgrade the change buffer after all redo log has been applied. */ +dberr_t ibuf_upgrade(); |