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/*****************************************************************************
Copyright (c) 1994, 2015, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2018, 2022, 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
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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file include/btr0cur.ic
The index tree cursor
Created 10/16/1994 Heikki Tuuri
*******************************************************/
#include "btr0btr.h"
#ifdef UNIV_DEBUG
# define LIMIT_OPTIMISTIC_INSERT_DEBUG(NREC, CODE)\
if (btr_cur_limit_optimistic_insert_debug > 1\
&& (NREC) >= btr_cur_limit_optimistic_insert_debug) {\
CODE;\
}
#else
# define LIMIT_OPTIMISTIC_INSERT_DEBUG(NREC, CODE)
#endif /* UNIV_DEBUG */
/*********************************************************//**
Returns the compressed page on which the tree cursor is positioned.
@return pointer to compressed page, or NULL if the page is not compressed */
UNIV_INLINE
page_zip_des_t*
btr_cur_get_page_zip(
/*=================*/
btr_cur_t* cursor) /*!< in: tree cursor */
{
return(buf_block_get_page_zip(btr_cur_get_block(cursor)));
}
/*********************************************************//**
Returns the page of a tree cursor.
@return pointer to page */
UNIV_INLINE
page_t*
btr_cur_get_page(
/*=============*/
btr_cur_t* cursor) /*!< in: tree cursor */
{
return(page_align(page_cur_get_rec(&(cursor->page_cur))));
}
/*********************************************************//**
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 */
{
page_cur_position(rec, block, btr_cur_get_page_cur(cursor));
cursor->page_cur.index = index;
}
/*********************************************************************//**
Checks if compressing an index page where a btr cursor is placed makes
sense.
@return TRUE if compression is recommended */
UNIV_INLINE
ibool
btr_cur_compress_recommendation(
/*============================*/
btr_cur_t* cursor, /*!< in: btr cursor */
mtr_t* mtr) /*!< in: mtr */
{
const page_t* page;
ut_ad(mtr->memo_contains_flagged(btr_cur_get_block(cursor),
MTR_MEMO_PAGE_X_FIX));
page = btr_cur_get_page(cursor);
LIMIT_OPTIMISTIC_INSERT_DEBUG(page_get_n_recs(page) * 2U,
return(FALSE));
if (!page_has_siblings(page)
|| page_get_data_size(page)
< BTR_CUR_PAGE_COMPRESS_LIMIT(cursor->index())) {
/* 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 cursor->index()->page
!= btr_cur_get_block(cursor)->page.id().page_no();
}
return(FALSE);
}
/*********************************************************************//**
Checks if the record on which the cursor is placed can be deleted without
making tree compression necessary (or, recommended).
@return TRUE if can be deleted without recommended compression */
UNIV_INLINE
ibool
btr_cur_can_delete_without_compress(
/*================================*/
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_flagged(btr_cur_get_block(cursor),
MTR_MEMO_PAGE_X_FIX));
page = btr_cur_get_page(cursor);
if (!page_has_siblings(page) || page_get_n_recs(page) < 2
|| page_get_data_size(page) - rec_size
< BTR_CUR_PAGE_COMPRESS_LIMIT(cursor->index())) {
/* 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 cursor->index()->page
== btr_cur_get_block(cursor)->page.id().page_no();
}
return(TRUE);
}
/*******************************************************************//**
Determine if an operation on off-page columns is an update.
@return TRUE if op != BTR_STORE_INSERT */
UNIV_INLINE
ibool
btr_blob_op_is_update(
/*==================*/
enum blob_op op) /*!< in: operation */
{
switch (op) {
case BTR_STORE_INSERT:
case BTR_STORE_INSERT_BULK:
return(FALSE);
case BTR_STORE_INSERT_UPDATE:
case BTR_STORE_UPDATE:
return(TRUE);
}
ut_ad(0);
return(FALSE);
}
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