/***************************************************************************** Copyright (c) 1994, 2010, Innobase Oy. All Rights Reserved. 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 Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *****************************************************************************/ /**************************************************//** @file include/btr0btr.h The B-tree Created 6/2/1994 Heikki Tuuri *******************************************************/ #ifndef btr0btr_h #define btr0btr_h #include "univ.i" #include "dict0dict.h" #include "data0data.h" #include "page0cur.h" #include "mtr0mtr.h" #include "btr0types.h" #ifndef UNIV_HOTBACKUP /** Maximum record size which can be stored on a page, without using the special big record storage structure */ #define BTR_PAGE_MAX_REC_SIZE (UNIV_PAGE_SIZE / 2 - 200) /** @brief Maximum depth of a B-tree in InnoDB. Note that this isn't a maximum as such; none of the tree operations avoid producing trees bigger than this. It is instead a "max depth that other code must work with", useful for e.g. fixed-size arrays that must store some information about each level in a tree. In other words: if a B-tree with bigger depth than this is encountered, it is not acceptable for it to lead to mysterious memory corruption, but it is acceptable for the program to die with a clear assert failure. */ #define BTR_MAX_LEVELS 100 /** Latching modes for btr_cur_search_to_nth_level(). */ enum btr_latch_mode { /** Search a record on a leaf page and S-latch it. */ BTR_SEARCH_LEAF = RW_S_LATCH, /** (Prepare to) modify a record on a leaf page and X-latch it. */ BTR_MODIFY_LEAF = RW_X_LATCH, /** Obtain no latches. */ BTR_NO_LATCHES = RW_NO_LATCH, /** Start modifying the entire B-tree. */ BTR_MODIFY_TREE = 33, /** Continue modifying the entire B-tree. */ BTR_CONT_MODIFY_TREE = 34, /** Search the previous record. */ BTR_SEARCH_PREV = 35, /** Modify the previous record. */ BTR_MODIFY_PREV = 36 }; /* BTR_INSERT, BTR_DELETE and BTR_DELETE_MARK are mutually exclusive. */ /** If this is ORed to btr_latch_mode, it means that the search tuple will be inserted to the index, at the searched position. When the record is not in the buffer pool, try to use the insert buffer. */ #define BTR_INSERT 512 /** This flag ORed to btr_latch_mode says that we do the search in query optimization */ #define BTR_ESTIMATE 1024 /** This flag ORed to BTR_INSERT says that we can ignore possible UNIQUE definition on secondary indexes when we decide if we can use the insert buffer to speed up inserts */ #define BTR_IGNORE_SEC_UNIQUE 2048 /** Try to delete mark the record at the searched position using the insert/delete buffer when the record is not in the buffer pool. */ #define BTR_DELETE_MARK 4096 /** Try to purge the record at the searched position using the insert/delete buffer when the record is not in the buffer pool. */ #define BTR_DELETE 8192 #ifdef UNIV_BLOB_DEBUG # include "ut0rbt.h" /** An index->blobs entry for keeping track of off-page column references */ struct btr_blob_dbg_struct { unsigned blob_page_no:32; /*!< first BLOB page number */ unsigned ref_page_no:32; /*!< referring page number */ unsigned ref_heap_no:16; /*!< referring heap number */ unsigned ref_field_no:10; /*!< referring field number */ unsigned owner:1; /*!< TRUE if BLOB owner */ unsigned always_owner:1; /*!< TRUE if always has been the BLOB owner; reset to TRUE on B-tree page splits and merges */ unsigned del:1; /*!< TRUE if currently delete-marked */ }; /**************************************************************//** Add a reference to an off-page column to the index->blobs map. */ UNIV_INTERN void btr_blob_dbg_add_blob( /*==================*/ const rec_t* rec, /*!< in: clustered index record */ ulint field_no, /*!< in: number of off-page column */ ulint page_no, /*!< in: start page of the column */ dict_index_t* index, /*!< in/out: index tree */ const char* ctx) /*!< in: context (for logging) */ __attribute__((nonnull)); /**************************************************************//** Display the references to off-page columns. This function is to be called from a debugger, for example when a breakpoint on ut_dbg_assertion_failed is hit. */ UNIV_INTERN void btr_blob_dbg_print( /*===============*/ const dict_index_t* index) /*!< in: index tree */ __attribute__((nonnull)); /**************************************************************//** Check that there are no references to off-page columns from or to the given page. Invoked when freeing or clearing a page. @return TRUE when no orphan references exist */ UNIV_INTERN ibool btr_blob_dbg_is_empty( /*==================*/ dict_index_t* index, /*!< in: index */ ulint page_no) /*!< in: page number */ __attribute__((nonnull, warn_unused_result)); /**************************************************************//** Modify the 'deleted' flag of a record. */ UNIV_INTERN void btr_blob_dbg_set_deleted_flag( /*==========================*/ const rec_t* rec, /*!< in: record */ dict_index_t* index, /*!< in/out: index */ const ulint* offsets,/*!< in: rec_get_offs(rec, index) */ ibool del) /*!< in: TRUE=deleted, FALSE=exists */ __attribute__((nonnull)); /**************************************************************//** Change the ownership of an off-page column. */ UNIV_INTERN void btr_blob_dbg_owner( /*===============*/ const rec_t* rec, /*!< in: record */ dict_index_t* index, /*!< in/out: index */ const ulint* offsets,/*!< in: rec_get_offs(rec, index) */ ulint i, /*!< in: ith field in rec */ ibool own) /*!< in: TRUE=owned, FALSE=disowned */ __attribute__((nonnull)); /** Assert that there are no BLOB references to or from the given page. */ # define btr_blob_dbg_assert_empty(index, page_no) \ ut_a(btr_blob_dbg_is_empty(index, page_no)) #else /* UNIV_BLOB_DEBUG */ # define btr_blob_dbg_add_blob(rec, field_no, page, index, ctx) ((void) 0) # define btr_blob_dbg_set_deleted_flag(rec, index, offsets, del)((void) 0) # define btr_blob_dbg_owner(rec, index, offsets, i, val) ((void) 0) # define btr_blob_dbg_assert_empty(index, page_no) ((void) 0) #endif /* UNIV_BLOB_DEBUG */ /**************************************************************//** Gets the root node of a tree and x-latches it. @return root page, x-latched */ UNIV_INTERN page_t* btr_root_get( /*=========*/ dict_index_t* index, /*!< in: index tree */ mtr_t* mtr); /*!< in: mtr */ /**************************************************************//** Gets a buffer page and declares its latching order level. */ UNIV_INLINE buf_block_t* btr_block_get_func( /*===============*/ ulint space, /*!< in: space id */ ulint zip_size, /*!< in: compressed page size in bytes or 0 for uncompressed pages */ ulint page_no, /*!< in: page number */ ulint mode, /*!< in: latch mode */ const char* file, /*!< in: file name */ ulint line, /*!< in: line where called */ mtr_t* mtr) /*!< in/out: mtr */ __attribute__((nonnull)); /** Gets a buffer page and declares its latching order level. @param space tablespace identifier @param zip_size compressed page size in bytes or 0 for uncompressed pages @param page_no page number @param mode latch mode @param mtr mini-transaction handle @return the block descriptor */ # define btr_block_get(space,zip_size,page_no,mode,mtr) \ btr_block_get_func(space,zip_size,page_no,mode,__FILE__,__LINE__,mtr) /** Gets a buffer page and declares its latching order level. @param space tablespace identifier @param zip_size compressed page size in bytes or 0 for uncompressed pages @param page_no page number @param mode latch mode @param mtr mini-transaction handle @return the uncompressed page frame */ # define btr_page_get(space,zip_size,page_no,mode,mtr) \ buf_block_get_frame(btr_block_get(space,zip_size,page_no,mode,mtr)) /**************************************************************//** Sets the index id field of a page. */ UNIV_INLINE void btr_page_set_index_id( /*==================*/ page_t* page, /*!< in: page to be created */ page_zip_des_t* page_zip,/*!< in: compressed page whose uncompressed part will be updated, or NULL */ index_id_t id, /*!< in: index id */ mtr_t* mtr); /*!< in: mtr */ #endif /* !UNIV_HOTBACKUP */ /**************************************************************//** Gets the index id field of a page. @return index id */ UNIV_INLINE index_id_t btr_page_get_index_id( /*==================*/ const page_t* page); /*!< in: index page */ #ifndef UNIV_HOTBACKUP /********************************************************//** Gets the node level field in an index page. @return level, leaf level == 0 */ UNIV_INLINE ulint btr_page_get_level_low( /*===================*/ const page_t* page); /*!< in: index page */ /********************************************************//** Gets the node level field in an index page. @return level, leaf level == 0 */ UNIV_INLINE ulint btr_page_get_level( /*===============*/ const page_t* page, /*!< in: index page */ mtr_t* mtr); /*!< in: mini-transaction handle */ /********************************************************//** Gets the next index page number. @return next page number */ UNIV_INLINE ulint btr_page_get_next( /*==============*/ const page_t* page, /*!< in: index page */ mtr_t* mtr); /*!< in: mini-transaction handle */ /********************************************************//** Sets the next index page field. */ UNIV_INLINE void btr_page_set_next( /*==============*/ page_t* page, /*!< in: index page */ page_zip_des_t* page_zip,/*!< in: compressed page whose uncompressed part will be updated, or NULL */ ulint next, /*!< in: next page number */ mtr_t* mtr); /*!< in: mini-transaction handle */ /********************************************************//** Gets the previous index page number. @return prev page number */ UNIV_INLINE ulint btr_page_get_prev( /*==============*/ const page_t* page, /*!< in: index page */ mtr_t* mtr); /*!< in: mini-transaction handle */ /********************************************************//** Sets the previous index page field. */ UNIV_INLINE void btr_page_set_prev( /*==============*/ page_t* page, /*!< in: index page */ page_zip_des_t* page_zip,/*!< in: compressed page whose uncompressed part will be updated, or NULL */ ulint prev, /*!< in: previous page number */ mtr_t* mtr); /*!< in: mini-transaction handle */ /*************************************************************//** Gets pointer to the previous user record in the tree. It is assumed that the caller has appropriate latches on the page and its neighbor. @return previous user record, NULL if there is none */ UNIV_INTERN rec_t* btr_get_prev_user_rec( /*==================*/ rec_t* rec, /*!< in: record on leaf level */ mtr_t* mtr); /*!< in: mtr holding a latch on the page, and if needed, also to the previous page */ /*************************************************************//** Gets pointer to the next user record in the tree. It is assumed that the caller has appropriate latches on the page and its neighbor. @return next user record, NULL if there is none */ UNIV_INTERN rec_t* btr_get_next_user_rec( /*==================*/ rec_t* rec, /*!< in: record on leaf level */ mtr_t* mtr); /*!< in: mtr holding a latch on the page, and if needed, also to the next page */ /**************************************************************//** Releases the latch on a leaf page and bufferunfixes it. */ UNIV_INLINE void btr_leaf_page_release( /*==================*/ buf_block_t* block, /*!< in: buffer block */ ulint latch_mode, /*!< in: BTR_SEARCH_LEAF or BTR_MODIFY_LEAF */ mtr_t* mtr); /*!< in: mtr */ /**************************************************************//** Gets the child node file address in a node pointer. NOTE: the offsets array must contain all offsets for the record since we read the last field according to offsets and assume that it contains the child page number. In other words offsets must have been retrieved with rec_get_offsets(n_fields=ULINT_UNDEFINED). @return child node address */ UNIV_INLINE ulint btr_node_ptr_get_child_page_no( /*===========================*/ const rec_t* rec, /*!< in: node pointer record */ const ulint* offsets);/*!< in: array returned by rec_get_offsets() */ /**************************************************************//** Creates a new index page (not the root, and also not used in page reorganization). @see btr_page_empty(). */ UNIV_INTERN void btr_page_create( /*============*/ buf_block_t* block, /*!< in/out: page to be created */ page_zip_des_t* page_zip,/*!< in/out: compressed page, or NULL */ dict_index_t* index, /*!< in: index */ ulint level, /*!< in: the B-tree level of the page */ mtr_t* mtr); /*!< in: mtr */ /************************************************************//** Creates the root node for a new index tree. @return page number of the created root, FIL_NULL if did not succeed */ UNIV_INTERN ulint btr_create( /*=======*/ ulint type, /*!< in: type of the index */ ulint space, /*!< in: space where created */ ulint zip_size,/*!< in: compressed page size in bytes or 0 for uncompressed pages */ index_id_t index_id,/*!< in: index id */ dict_index_t* index, /*!< in: index */ mtr_t* mtr); /*!< in: mini-transaction handle */ /************************************************************//** Frees a B-tree except the root page, which MUST be freed after this by calling btr_free_root. */ UNIV_INTERN void btr_free_but_not_root( /*==================*/ ulint space, /*!< in: space where created */ ulint zip_size, /*!< in: compressed page size in bytes or 0 for uncompressed pages */ ulint root_page_no); /*!< in: root page number */ /************************************************************//** Frees the B-tree root page. Other tree MUST already have been freed. */ UNIV_INTERN void btr_free_root( /*==========*/ ulint space, /*!< in: space where created */ ulint zip_size, /*!< in: compressed page size in bytes or 0 for uncompressed pages */ ulint root_page_no, /*!< in: root page number */ mtr_t* mtr); /*!< in: a mini-transaction which has already been started */ /*************************************************************//** Makes tree one level higher by splitting the root, and inserts the tuple. It is assumed that mtr contains an x-latch on the tree. NOTE that the operation of this function must always succeed, we cannot reverse it: therefore enough free disk space must be guaranteed to be available before this function is called. @return inserted record */ UNIV_INTERN rec_t* btr_root_raise_and_insert( /*======================*/ btr_cur_t* cursor, /*!< in: cursor at which to insert: must be on the root page; when the function returns, the cursor is positioned on the predecessor of the inserted record */ const dtuple_t* tuple, /*!< in: tuple to insert */ ulint n_ext, /*!< in: number of externally stored columns */ mtr_t* mtr); /*!< in: mtr */ /*************************************************************//** Reorganizes an index page. IMPORTANT: if btr_page_reorganize() is invoked on a compressed leaf page of a non-clustered index, the caller must update the insert buffer free bits in the same mini-transaction in such a way that the modification will be redo-logged. @return TRUE on success, FALSE on failure */ UNIV_INTERN ibool btr_page_reorganize( /*================*/ buf_block_t* block, /*!< in: page to be reorganized */ dict_index_t* index, /*!< in: record descriptor */ mtr_t* mtr); /*!< in: mtr */ /*************************************************************//** Empties an index page. @see btr_page_create(). */ UNIV_INTERN void btr_page_empty( /*===========*/ buf_block_t* block, /*!< in: page to be emptied */ page_zip_des_t* page_zip,/*!< out: compressed page, or NULL */ dict_index_t* index, /*!< in: index of the page */ ulint level, /*!< in: the B-tree level of the page */ mtr_t* mtr); /*!< in: mtr */ /*************************************************************//** Decides if the page should be split at the convergence point of inserts converging to left. @return TRUE if split recommended */ UNIV_INTERN ibool btr_page_get_split_rec_to_left( /*===========================*/ btr_cur_t* cursor, /*!< in: cursor at which to insert */ rec_t** split_rec);/*!< out: if split recommended, the first record on upper half page, or NULL if tuple should be first */ /*************************************************************//** Decides if the page should be split at the convergence point of inserts converging to right. @return TRUE if split recommended */ UNIV_INTERN ibool btr_page_get_split_rec_to_right( /*============================*/ btr_cur_t* cursor, /*!< in: cursor at which to insert */ rec_t** split_rec);/*!< out: if split recommended, the first record on upper half page, or NULL if tuple should be first */ /*************************************************************//** Splits an index page to halves and inserts the tuple. It is assumed that mtr holds an x-latch to the index tree. NOTE: the tree x-latch is released within this function! NOTE that the operation of this function must always succeed, we cannot reverse it: therefore enough free disk space (2 pages) must be guaranteed to be available before this function is called. @return inserted record */ UNIV_INTERN rec_t* btr_page_split_and_insert( /*======================*/ btr_cur_t* cursor, /*!< in: cursor at which to insert; when the function returns, the cursor is positioned on the predecessor of the inserted record */ const dtuple_t* tuple, /*!< in: tuple to insert */ ulint n_ext, /*!< in: number of externally stored columns */ mtr_t* mtr); /*!< in: mtr */ /*******************************************************//** Inserts a data tuple to a tree on a non-leaf level. It is assumed that mtr holds an x-latch on the tree. */ UNIV_INTERN void btr_insert_on_non_leaf_level_func( /*==============================*/ dict_index_t* index, /*!< in: index */ ulint level, /*!< in: level, must be > 0 */ dtuple_t* tuple, /*!< in: the record to be inserted */ const char* file, /*!< in: file name */ ulint line, /*!< in: line where called */ mtr_t* mtr); /*!< in: mtr */ # define btr_insert_on_non_leaf_level(i,l,t,m) \ btr_insert_on_non_leaf_level_func(i,l,t,__FILE__,__LINE__,m) #endif /* !UNIV_HOTBACKUP */ /**************************************************************//** Attaches the halves of an index page on the appropriate level in an index tree. */ UNIV_INTERN void btr_attach_half_pages( /*==================*/ dict_index_t* index, /*!< in: the index tree */ buf_block_t* block, /*!< in/out: page to be split */ rec_t* split_rec, /*!< in: first record on upper half page */ buf_block_t* new_block, /*!< in/out: the new half page */ ulint direction, /*!< in: FSP_UP or FSP_DOWN */ mtr_t* mtr); /*!< in: mtr */ /****************************************************************//** Sets a record as the predefined minimum record. */ UNIV_INTERN void btr_set_min_rec_mark( /*=================*/ rec_t* rec, /*!< in/out: record */ mtr_t* mtr); /*!< in: mtr */ #ifndef UNIV_HOTBACKUP /*************************************************************//** Deletes on the upper level the node pointer to a page. */ UNIV_INTERN void btr_node_ptr_delete( /*================*/ dict_index_t* index, /*!< in: index tree */ buf_block_t* block, /*!< in: page whose node pointer is deleted */ mtr_t* mtr); /*!< in: mtr */ #ifdef UNIV_DEBUG /************************************************************//** Checks that the node pointer to a page is appropriate. @return TRUE */ UNIV_INTERN ibool btr_check_node_ptr( /*===============*/ dict_index_t* index, /*!< in: index tree */ buf_block_t* block, /*!< in: index page */ mtr_t* mtr); /*!< in: mtr */ #endif /* UNIV_DEBUG */ /*************************************************************//** Tries to merge the page first to the left immediate brother if such a brother exists, and the node pointers to the current page and to the brother reside on the same page. If the left brother does not satisfy these conditions, looks at the right brother. If the page is the only one on that level lifts the records of the page to the father page, thus reducing the tree height. It is assumed that mtr holds an x-latch on the tree and on the page. If cursor is on the leaf level, mtr must also hold x-latches to the brothers, if they exist. @return TRUE on success */ UNIV_INTERN ibool btr_compress( /*=========*/ btr_cur_t* cursor, /*!< in: cursor on the page to merge or lift; the page must not be empty: in record delete use btr_discard_page if the page would become empty */ mtr_t* mtr); /*!< in: mtr */ /*************************************************************//** Discards a page from a B-tree. This is used to remove the last record from a B-tree page: the whole page must be removed at the same time. This cannot be used for the root page, which is allowed to be empty. */ UNIV_INTERN void btr_discard_page( /*=============*/ btr_cur_t* cursor, /*!< in: cursor on the page to discard: not on the root page */ mtr_t* mtr); /*!< in: mtr */ #endif /* !UNIV_HOTBACKUP */ /****************************************************************//** Parses the redo log record for setting an index record as the predefined minimum record. @return end of log record or NULL */ UNIV_INTERN byte* btr_parse_set_min_rec_mark( /*=======================*/ byte* ptr, /*!< in: buffer */ byte* end_ptr,/*!< in: buffer end */ ulint comp, /*!< in: nonzero=compact page format */ page_t* page, /*!< in: page or NULL */ mtr_t* mtr); /*!< in: mtr or NULL */ /***********************************************************//** Parses a redo log record of reorganizing a page. @return end of log record or NULL */ UNIV_INTERN byte* btr_parse_page_reorganize( /*======================*/ byte* ptr, /*!< in: buffer */ byte* end_ptr,/*!< in: buffer end */ dict_index_t* index, /*!< in: record descriptor */ buf_block_t* block, /*!< in: page to be reorganized, or NULL */ mtr_t* mtr); /*!< in: mtr or NULL */ #ifndef UNIV_HOTBACKUP /**************************************************************//** Gets the number of pages in a B-tree. @return number of pages */ UNIV_INTERN ulint btr_get_size( /*=========*/ dict_index_t* index, /*!< in: index */ ulint flag); /*!< in: BTR_N_LEAF_PAGES or BTR_TOTAL_SIZE */ /**************************************************************//** Allocates a new file page to be used in an index tree. NOTE: we assume that the caller has made the reservation for free extents! @return new allocated block, x-latched; NULL if out of space */ UNIV_INTERN buf_block_t* btr_page_alloc( /*===========*/ dict_index_t* index, /*!< in: index tree */ ulint hint_page_no, /*!< in: hint of a good page */ byte file_direction, /*!< in: direction where a possible page split is made */ ulint level, /*!< in: level where the page is placed in the tree */ mtr_t* mtr); /*!< in: mtr */ /**************************************************************//** Frees a file page used in an index tree. NOTE: cannot free field external storage pages because the page must contain info on its level. */ UNIV_INTERN void btr_page_free( /*==========*/ dict_index_t* index, /*!< in: index tree */ buf_block_t* block, /*!< in: block to be freed, x-latched */ mtr_t* mtr); /*!< in: mtr */ /**************************************************************//** Frees a file page used in an index tree. Can be used also to BLOB external storage pages, because the page level 0 can be given as an argument. */ UNIV_INTERN void btr_page_free_low( /*==============*/ dict_index_t* index, /*!< in: index tree */ buf_block_t* block, /*!< in: block to be freed, x-latched */ ulint level, /*!< in: page level */ mtr_t* mtr); /*!< in: mtr */ #ifdef UNIV_BTR_PRINT /*************************************************************//** Prints size info of a B-tree. */ UNIV_INTERN void btr_print_size( /*===========*/ dict_index_t* index); /*!< in: index tree */ /**************************************************************//** Prints directories and other info of all nodes in the index. */ UNIV_INTERN void btr_print_index( /*============*/ dict_index_t* index, /*!< in: index */ ulint width); /*!< in: print this many entries from start and end */ #endif /* UNIV_BTR_PRINT */ /************************************************************//** Checks the size and number of fields in a record based on the definition of the index. @return TRUE if ok */ UNIV_INTERN ibool btr_index_rec_validate( /*===================*/ const rec_t* rec, /*!< in: index record */ const dict_index_t* index, /*!< in: index */ ibool dump_on_error); /*!< in: TRUE if the function should print hex dump of record and page on error */ /**************************************************************//** Checks the consistency of an index tree. @return TRUE if ok */ UNIV_INTERN ibool btr_validate_index( /*===============*/ dict_index_t* index, /*!< in: index */ trx_t* trx); /*!< in: transaction or NULL */ #define BTR_N_LEAF_PAGES 1 #define BTR_TOTAL_SIZE 2 #endif /* !UNIV_HOTBACKUP */ #ifndef UNIV_NONINL #include "btr0btr.ic" #endif #endif