mariadb/storage/innobase/include/fsp0fsp.h
2012-02-17 11:52:51 +02:00

463 lines
18 KiB
C

/*****************************************************************************
Copyright (c) 1995, 2012, Oracle and/or its affiliates. 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.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file include/fsp0fsp.h
File space management
Created 12/18/1995 Heikki Tuuri
*******************************************************/
#ifndef fsp0fsp_h
#define fsp0fsp_h
#include "univ.i"
#include "mtr0mtr.h"
#include "fut0lst.h"
#include "ut0byte.h"
#include "page0types.h"
#include "fsp0types.h"
/* @defgroup fsp_flags InnoDB Tablespace Flag Constants @{ */
/** Number of flag bits used to indicate the tablespace page size */
#define FSP_FLAGS_WIDTH_PAGE_SSIZE 4
/** Zero relative shift position of the PAGE_SSIZE field */
#define FSP_FLAGS_POS_PAGE_SSIZE 6
/** Bit mask of the PAGE_SSIZE field */
#define FSP_FLAGS_MASK_PAGE_SSIZE \
((~(~0 << FSP_FLAGS_WIDTH_PAGE_SSIZE)) \
<< FSP_FLAGS_POS_PAGE_SSIZE)
/** Return the value of the PAGE_SSIZE field */
#define FSP_FLAGS_GET_PAGE_SSIZE(flags) \
((flags & FSP_FLAGS_MASK_PAGE_SSIZE) \
>> FSP_FLAGS_POS_PAGE_SSIZE)
/* @} */
/* @defgroup Tablespace Header Constants (moved from fsp0fsp.c) @{ */
/** Offset of the space header within a file page */
#define FSP_HEADER_OFFSET FIL_PAGE_DATA
/* The data structures in files are defined just as byte strings in C */
typedef byte fsp_header_t;
typedef byte xdes_t;
/* SPACE HEADER
============
File space header data structure: this data structure is contained in the
first page of a space. The space for this header is reserved in every extent
descriptor page, but used only in the first. */
/*-------------------------------------*/
#define FSP_SPACE_ID 0 /* space id */
#define FSP_NOT_USED 4 /* this field contained a value up to
which we know that the modifications
in the database have been flushed to
the file space; not used now */
#define FSP_SIZE 8 /* Current size of the space in
pages */
#define FSP_FREE_LIMIT 12 /* Minimum page number for which the
free list has not been initialized:
the pages >= this limit are, by
definition, free; note that in a
single-table tablespace where size
< 64 pages, this number is 64, i.e.,
we have initialized the space
about the first extent, but have not
physically allocted those pages to the
file */
#define FSP_SPACE_FLAGS 16 /* fsp_space_t.flags, similar to
dict_table_t::flags */
#define FSP_FRAG_N_USED 20 /* number of used pages in the
FSP_FREE_FRAG list */
#define FSP_FREE 24 /* list of free extents */
#define FSP_FREE_FRAG (24 + FLST_BASE_NODE_SIZE)
/* list of partially free extents not
belonging to any segment */
#define FSP_FULL_FRAG (24 + 2 * FLST_BASE_NODE_SIZE)
/* list of full extents not belonging
to any segment */
#define FSP_SEG_ID (24 + 3 * FLST_BASE_NODE_SIZE)
/* 8 bytes which give the first unused
segment id */
#define FSP_SEG_INODES_FULL (32 + 3 * FLST_BASE_NODE_SIZE)
/* list of pages containing segment
headers, where all the segment inode
slots are reserved */
#define FSP_SEG_INODES_FREE (32 + 4 * FLST_BASE_NODE_SIZE)
/* list of pages containing segment
headers, where not all the segment
header slots are reserved */
/*-------------------------------------*/
/* File space header size */
#define FSP_HEADER_SIZE (32 + 5 * FLST_BASE_NODE_SIZE)
#define FSP_FREE_ADD 4 /* this many free extents are added
to the free list from above
FSP_FREE_LIMIT at a time */
/* @} */
/* @} */
/**********************************************************************//**
Initializes the file space system. */
UNIV_INTERN
void
fsp_init(void);
/*==========*/
/**********************************************************************//**
Gets the current free limit of the system tablespace. The free limit
means the place of the first page which has never been put to the
free list for allocation. The space above that address is initialized
to zero. Sets also the global variable log_fsp_current_free_limit.
@return free limit in megabytes */
UNIV_INTERN
ulint
fsp_header_get_free_limit(void);
/*===========================*/
/**********************************************************************//**
Gets the size of the system tablespace from the tablespace header. If
we do not have an auto-extending data file, this should be equal to
the size of the data files. If there is an auto-extending data file,
this can be smaller.
@return size in pages */
UNIV_INTERN
ulint
fsp_header_get_tablespace_size(void);
/*================================*/
/**********************************************************************//**
Reads the file space size stored in the header page.
@return tablespace size stored in the space header */
UNIV_INTERN
ulint
fsp_get_size_low(
/*=============*/
page_t* page); /*!< in: header page (page 0 in the tablespace) */
/**********************************************************************//**
Reads the space id from the first page of a tablespace.
@return space id, ULINT UNDEFINED if error */
UNIV_INTERN
ulint
fsp_header_get_space_id(
/*====================*/
const page_t* page); /*!< in: first page of a tablespace */
/**********************************************************************//**
Reads the space flags from the first page of a tablespace.
@return flags */
UNIV_INTERN
ulint
fsp_header_get_flags(
/*=================*/
const page_t* page); /*!< in: first page of a tablespace */
/**********************************************************************//**
Reads the compressed page size from the first page of a tablespace.
@return compressed page size in bytes, or 0 if uncompressed */
UNIV_INTERN
ulint
fsp_header_get_zip_size(
/*====================*/
const page_t* page); /*!< in: first page of a tablespace */
/**********************************************************************//**
Writes the space id and compressed page size to a tablespace header.
This function is used past the buffer pool when we in fil0fil.c create
a new single-table tablespace. */
UNIV_INTERN
void
fsp_header_init_fields(
/*===================*/
page_t* page, /*!< in/out: first page in the space */
ulint space_id, /*!< in: space id */
ulint flags); /*!< in: tablespace flags (FSP_SPACE_FLAGS):
0, or table->flags if newer than COMPACT */
/**********************************************************************//**
Initializes the space header of a new created space and creates also the
insert buffer tree root if space == 0. */
UNIV_INTERN
void
fsp_header_init(
/*============*/
ulint space, /*!< in: space id */
ulint size, /*!< in: current size in blocks */
mtr_t* mtr); /*!< in: mini-transaction handle */
/**********************************************************************//**
Increases the space size field of a space. */
UNIV_INTERN
void
fsp_header_inc_size(
/*================*/
ulint space, /*!< in: space id */
ulint size_inc,/*!< in: size increment in pages */
mtr_t* mtr); /*!< in: mini-transaction handle */
/**********************************************************************//**
Creates a new segment.
@return the block where the segment header is placed, x-latched, NULL
if could not create segment because of lack of space */
UNIV_INTERN
buf_block_t*
fseg_create(
/*========*/
ulint space, /*!< in: space id */
ulint page, /*!< in: page where the segment header is placed: if
this is != 0, the page must belong to another segment,
if this is 0, a new page will be allocated and it
will belong to the created segment */
ulint byte_offset, /*!< in: byte offset of the created segment header
on the page */
mtr_t* mtr); /*!< in: mtr */
/**********************************************************************//**
Creates a new segment.
@return the block where the segment header is placed, x-latched, NULL
if could not create segment because of lack of space */
UNIV_INTERN
buf_block_t*
fseg_create_general(
/*================*/
ulint space, /*!< in: space id */
ulint page, /*!< in: page where the segment header is placed: if
this is != 0, the page must belong to another segment,
if this is 0, a new page will be allocated and it
will belong to the created segment */
ulint byte_offset, /*!< in: byte offset of the created segment header
on the page */
ibool has_done_reservation, /*!< in: TRUE if the caller has already
done the reservation for the pages with
fsp_reserve_free_extents (at least 2 extents: one for
the inode and the other for the segment) then there is
no need to do the check for this individual
operation */
mtr_t* mtr); /*!< in: mtr */
/**********************************************************************//**
Calculates the number of pages reserved by a segment, and how many pages are
currently used.
@return number of reserved pages */
UNIV_INTERN
ulint
fseg_n_reserved_pages(
/*==================*/
fseg_header_t* header, /*!< in: segment header */
ulint* used, /*!< out: number of pages used (<= reserved) */
mtr_t* mtr); /*!< in: mtr handle */
/**********************************************************************//**
Allocates a single free page from a segment. This function implements
the intelligent allocation strategy which tries to minimize
file space fragmentation.
@param[in/out] seg_header segment header
@param[in] hint hint of which page would be desirable
@param[in] direction if the new page is needed because
of an index page split, and records are
inserted there in order, into which
direction they go alphabetically: FSP_DOWN,
FSP_UP, FSP_NO_DIR
@param[in/out] mtr mini-transaction
@return X-latched block, or NULL if no page could be allocated */
#define fseg_alloc_free_page(seg_header, hint, direction, mtr) \
fseg_alloc_free_page_general(seg_header, hint, direction, \
FALSE, mtr, mtr)
/**********************************************************************//**
Allocates a single free page from a segment. This function implements
the intelligent allocation strategy which tries to minimize file space
fragmentation.
@retval NULL if no page could be allocated
@retval block, rw_lock_x_lock_count(&block->lock) == 1 if allocation succeeded
(init_mtr == mtr, or the page was not previously freed in mtr)
@retval block (not allocated or initialized) otherwise */
UNIV_INTERN
buf_block_t*
fseg_alloc_free_page_general(
/*=========================*/
fseg_header_t* seg_header,/*!< in/out: segment header */
ulint hint, /*!< in: hint of which page would be
desirable */
byte direction,/*!< in: if the new page is needed because
of an index page split, and records are
inserted there in order, into which
direction they go alphabetically: FSP_DOWN,
FSP_UP, FSP_NO_DIR */
ibool has_done_reservation, /*!< in: TRUE if the caller has
already done the reservation for the page
with fsp_reserve_free_extents, then there
is no need to do the check for this individual
page */
mtr_t* mtr, /*!< in/out: mini-transaction */
mtr_t* init_mtr)/*!< in/out: mtr or another mini-transaction
in which the page should be initialized.
If init_mtr!=mtr, but the page is already
latched in mtr, do not initialize the page. */
__attribute__((warn_unused_result, nonnull));
/**********************************************************************//**
Reserves free pages from a tablespace. All mini-transactions which may
use several pages from the tablespace should call this function beforehand
and reserve enough free extents so that they certainly will be able
to do their operation, like a B-tree page split, fully. Reservations
must be released with function fil_space_release_free_extents!
The alloc_type below has the following meaning: FSP_NORMAL means an
operation which will probably result in more space usage, like an
insert in a B-tree; FSP_UNDO means allocation to undo logs: if we are
deleting rows, then this allocation will in the long run result in
less space usage (after a purge); FSP_CLEANING means allocation done
in a physical record delete (like in a purge) or other cleaning operation
which will result in less space usage in the long run. We prefer the latter
two types of allocation: when space is scarce, FSP_NORMAL allocations
will not succeed, but the latter two allocations will succeed, if possible.
The purpose is to avoid dead end where the database is full but the
user cannot free any space because these freeing operations temporarily
reserve some space.
Single-table tablespaces whose size is < 32 pages are a special case. In this
function we would liberally reserve several 64 page extents for every page
split or merge in a B-tree. But we do not want to waste disk space if the table
only occupies < 32 pages. That is why we apply different rules in that special
case, just ensuring that there are 3 free pages available.
@return TRUE if we were able to make the reservation */
UNIV_INTERN
ibool
fsp_reserve_free_extents(
/*=====================*/
ulint* n_reserved,/*!< out: number of extents actually reserved; if we
return TRUE and the tablespace size is < 64 pages,
then this can be 0, otherwise it is n_ext */
ulint space, /*!< in: space id */
ulint n_ext, /*!< in: number of extents to reserve */
ulint alloc_type,/*!< in: FSP_NORMAL, FSP_UNDO, or FSP_CLEANING */
mtr_t* mtr); /*!< in: mtr */
/**********************************************************************//**
This function should be used to get information on how much we still
will be able to insert new data to the database without running out the
tablespace. Only free extents are taken into account and we also subtract
the safety margin required by the above function fsp_reserve_free_extents.
@return available space in kB */
UNIV_INTERN
ullint
fsp_get_available_space_in_free_extents(
/*====================================*/
ulint space); /*!< in: space id */
/**********************************************************************//**
Frees a single page of a segment. */
UNIV_INTERN
void
fseg_free_page(
/*===========*/
fseg_header_t* seg_header, /*!< in: segment header */
ulint space, /*!< in: space id */
ulint page, /*!< in: page offset */
mtr_t* mtr); /*!< in: mtr handle */
/**********************************************************************//**
Frees part of a segment. This function can be used to free a segment
by repeatedly calling this function in different mini-transactions.
Doing the freeing in a single mini-transaction might result in
too big a mini-transaction.
@return TRUE if freeing completed */
UNIV_INTERN
ibool
fseg_free_step(
/*===========*/
fseg_header_t* header, /*!< in, own: segment header; NOTE: if the header
resides on the first page of the frag list
of the segment, this pointer becomes obsolete
after the last freeing step */
mtr_t* mtr); /*!< in: mtr */
/**********************************************************************//**
Frees part of a segment. Differs from fseg_free_step because this function
leaves the header page unfreed.
@return TRUE if freeing completed, except the header page */
UNIV_INTERN
ibool
fseg_free_step_not_header(
/*======================*/
fseg_header_t* header, /*!< in: segment header which must reside on
the first fragment page of the segment */
mtr_t* mtr); /*!< in: mtr */
/***********************************************************************//**
Checks if a page address is an extent descriptor page address.
@return TRUE if a descriptor page */
UNIV_INLINE
ibool
fsp_descr_page(
/*===========*/
ulint zip_size,/*!< in: compressed page size in bytes;
0 for uncompressed pages */
ulint page_no);/*!< in: page number */
/***********************************************************//**
Parses a redo log record of a file page init.
@return end of log record or NULL */
UNIV_INTERN
byte*
fsp_parse_init_file_page(
/*=====================*/
byte* ptr, /*!< in: buffer */
byte* end_ptr, /*!< in: buffer end */
buf_block_t* block); /*!< in: block or NULL */
/*******************************************************************//**
Validates the file space system and its segments.
@return TRUE if ok */
UNIV_INTERN
ibool
fsp_validate(
/*=========*/
ulint space); /*!< in: space id */
/*******************************************************************//**
Prints info of a file space. */
UNIV_INTERN
void
fsp_print(
/*======*/
ulint space); /*!< in: space id */
#ifdef UNIV_DEBUG
/*******************************************************************//**
Validates a segment.
@return TRUE if ok */
UNIV_INTERN
ibool
fseg_validate(
/*==========*/
fseg_header_t* header, /*!< in: segment header */
mtr_t* mtr); /*!< in: mtr */
#endif /* UNIV_DEBUG */
#ifdef UNIV_BTR_PRINT
/*******************************************************************//**
Writes info of a segment. */
UNIV_INTERN
void
fseg_print(
/*=======*/
fseg_header_t* header, /*!< in: segment header */
mtr_t* mtr); /*!< in: mtr */
#endif /* UNIV_BTR_PRINT */
/********************************************************************//**
Extract the page size from tablespace flags.
This feature, storing the page_ssize into the tablespace flags, is added
to InnoDB 5.6.4. This is here only to protect against a crash if a newer
database is opened with this code branch.
@return page size of the tablespace in bytes */
UNIV_INLINE
ulint
fsp_flags_get_page_size(
/*====================*/
ulint flags); /*!< in: tablespace flags */
#ifndef UNIV_NONINL
#include "fsp0fsp.ic"
#endif
#endif