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Diffstat (limited to 'storage/xtradb/include/btr0cur.ic')
| -rw-r--r-- | storage/xtradb/include/btr0cur.ic | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/storage/xtradb/include/btr0cur.ic b/storage/xtradb/include/btr0cur.ic new file mode 100644 index 00000000000..84a3a5cba0b --- /dev/null +++ b/storage/xtradb/include/btr0cur.ic @@ -0,0 +1,200 @@ +/***************************************************************************** + +Copyright (c) 1994, 2009, 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 + +*****************************************************************************/ + +/****************************************************** +The index tree cursor + +Created 10/16/1994 Heikki Tuuri +*******************************************************/ + +#include "btr0btr.h" + +#ifdef UNIV_DEBUG +/************************************************************* +Returns the page cursor component of a tree cursor. */ +UNIV_INLINE +page_cur_t* +btr_cur_get_page_cur( +/*=================*/ + /* out: pointer to page cursor + component */ + const btr_cur_t* cursor) /* in: tree cursor */ +{ + return(&((btr_cur_t*) cursor)->page_cur); +} +#endif /* UNIV_DEBUG */ +/************************************************************* +Returns the buffer block on which the tree cursor is positioned. */ +UNIV_INLINE +buf_block_t* +btr_cur_get_block( +/*==============*/ + /* out: pointer to buffer block */ + btr_cur_t* cursor) /* in: tree cursor */ +{ + return(page_cur_get_block(btr_cur_get_page_cur(cursor))); +} + +/************************************************************* +Returns the record pointer of a tree cursor. */ +UNIV_INLINE +rec_t* +btr_cur_get_rec( +/*============*/ + /* out: pointer to record */ + btr_cur_t* cursor) /* in: tree cursor */ +{ + return(page_cur_get_rec(&(cursor->page_cur))); +} + +/************************************************************* +Returns the compressed page on which the tree cursor is positioned. */ +UNIV_INLINE +page_zip_des_t* +btr_cur_get_page_zip( +/*=================*/ + /* out: pointer to compressed page, + or NULL if the page is not compressed */ + btr_cur_t* cursor) /* in: tree cursor */ +{ + return(buf_block_get_page_zip(btr_cur_get_block(cursor))); +} + +/************************************************************* +Invalidates a tree cursor by setting record pointer to NULL. */ +UNIV_INLINE +void +btr_cur_invalidate( +/*===============*/ + btr_cur_t* cursor) /* in: tree cursor */ +{ + page_cur_invalidate(&(cursor->page_cur)); +} + +/************************************************************* +Returns the page of a tree cursor. */ +UNIV_INLINE +page_t* +btr_cur_get_page( +/*=============*/ + /* out: pointer to page */ + btr_cur_t* cursor) /* in: tree cursor */ +{ + return(page_align(page_cur_get_rec(&(cursor->page_cur)))); +} + +/************************************************************* +Returns the index of a cursor. */ +UNIV_INLINE +dict_index_t* +btr_cur_get_index( +/*==============*/ + /* out: index */ + btr_cur_t* cursor) /* in: B-tree cursor */ +{ + return(cursor->index); +} + +/************************************************************* +Positions a tree cursor at a given record. */ +UNIV_INLINE +void +btr_cur_position( +/*=============*/ + dict_index_t* index, /* in: index */ + rec_t* rec, /* in: record in tree */ + buf_block_t* block, /* in: buffer block of rec */ + btr_cur_t* cursor) /* out: cursor */ +{ + ut_ad(page_align(rec) == block->frame); + + page_cur_position(rec, block, btr_cur_get_page_cur(cursor)); + + cursor->index = index; +} + +/************************************************************************* +Checks if compressing an index page where a btr cursor is placed makes +sense. */ +UNIV_INLINE +ibool +btr_cur_compress_recommendation( +/*============================*/ + /* out: TRUE if compression is recommended */ + btr_cur_t* cursor, /* in: btr cursor */ + mtr_t* mtr) /* in: mtr */ +{ + page_t* page; + + ut_ad(mtr_memo_contains(mtr, btr_cur_get_block(cursor), + MTR_MEMO_PAGE_X_FIX)); + + page = btr_cur_get_page(cursor); + + if ((page_get_data_size(page) < BTR_CUR_PAGE_COMPRESS_LIMIT) + || ((btr_page_get_next(page, mtr) == FIL_NULL) + && (btr_page_get_prev(page, mtr) == FIL_NULL))) { + + /* The page fillfactor has dropped below a predefined + minimum value OR the level in the B-tree contains just + one page: we recommend compression if this is not the + root page. */ + + return(dict_index_get_page(cursor->index) + != page_get_page_no(page)); + } + + return(FALSE); +} + +/************************************************************************* +Checks if the record on which the cursor is placed can be deleted without +making tree compression necessary (or, recommended). */ +UNIV_INLINE +ibool +btr_cur_can_delete_without_compress( +/*================================*/ + /* out: TRUE if can be deleted without + recommended compression */ + btr_cur_t* cursor, /* in: btr cursor */ + ulint rec_size,/* in: rec_get_size(btr_cur_get_rec(cursor))*/ + mtr_t* mtr) /* in: mtr */ +{ + page_t* page; + + ut_ad(mtr_memo_contains(mtr, btr_cur_get_block(cursor), + MTR_MEMO_PAGE_X_FIX)); + + page = btr_cur_get_page(cursor); + + if ((page_get_data_size(page) - rec_size < BTR_CUR_PAGE_COMPRESS_LIMIT) + || ((btr_page_get_next(page, mtr) == FIL_NULL) + && (btr_page_get_prev(page, mtr) == FIL_NULL)) + || (page_get_n_recs(page) < 2)) { + + /* The page fillfactor will drop below a predefined + minimum value, OR the level in the B-tree contains just + one page, OR the page will become empty: we recommend + compression if this is not the root page. */ + + return(dict_index_get_page(cursor->index) + == page_get_page_no(page)); + } + + return(TRUE); +} |