mariadb/storage/xtradb/include/trx0undo.ic
2015-04-27 23:37:51 +02:00

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/*****************************************************************************
Copyright (c) 1996, 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.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*****************************************************************************/
/**************************************************//**
@file include/trx0undo.ic
Transaction undo log
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "data0type.h"
#include "page0page.h"
#ifndef UNIV_HOTBACKUP
/***********************************************************************//**
Builds a roll pointer.
@return roll pointer */
UNIV_INLINE
roll_ptr_t
trx_undo_build_roll_ptr(
/*====================*/
ibool is_insert, /*!< in: TRUE if insert undo log */
ulint rseg_id, /*!< in: rollback segment id */
ulint page_no, /*!< in: page number */
ulint offset) /*!< in: offset of the undo entry within page */
{
roll_ptr_t roll_ptr;
#if DATA_ROLL_PTR_LEN != 7
# error "DATA_ROLL_PTR_LEN != 7"
#endif
ut_ad(is_insert == 0 || is_insert == 1);
ut_ad(rseg_id < TRX_SYS_N_RSEGS);
ut_ad(offset < 65536);
roll_ptr = (roll_ptr_t) is_insert << 55
| (roll_ptr_t) rseg_id << 48
| (roll_ptr_t) page_no << 16
| offset;
return(roll_ptr);
}
/***********************************************************************//**
Decodes a roll pointer. */
UNIV_INLINE
void
trx_undo_decode_roll_ptr(
/*=====================*/
roll_ptr_t roll_ptr, /*!< in: roll pointer */
ibool* is_insert, /*!< out: TRUE if insert undo log */
ulint* rseg_id, /*!< out: rollback segment id */
ulint* page_no, /*!< out: page number */
ulint* offset) /*!< out: offset of the undo
entry within page */
{
#if DATA_ROLL_PTR_LEN != 7
# error "DATA_ROLL_PTR_LEN != 7"
#endif
#if TRUE != 1
# error "TRUE != 1"
#endif
ut_ad(roll_ptr < (1ULL << 56));
*offset = (ulint) roll_ptr & 0xFFFF;
roll_ptr >>= 16;
*page_no = (ulint) roll_ptr & 0xFFFFFFFF;
roll_ptr >>= 32;
*rseg_id = (ulint) roll_ptr & 0x7F;
roll_ptr >>= 7;
*is_insert = (ibool) roll_ptr; /* TRUE==1 */
}
/***********************************************************************//**
Returns TRUE if the roll pointer is of the insert type.
@return TRUE if insert undo log */
UNIV_INLINE
ibool
trx_undo_roll_ptr_is_insert(
/*========================*/
roll_ptr_t roll_ptr) /*!< in: roll pointer */
{
#if DATA_ROLL_PTR_LEN != 7
# error "DATA_ROLL_PTR_LEN != 7"
#endif
#if TRUE != 1
# error "TRUE != 1"
#endif
ut_ad(roll_ptr < (1ULL << 56));
return((ibool) (roll_ptr >> 55));
}
#endif /* !UNIV_HOTBACKUP */
/*****************************************************************//**
Writes a roll ptr to an index page. In case that the size changes in
some future version, this function should be used instead of
mach_write_... */
UNIV_INLINE
void
trx_write_roll_ptr(
/*===============*/
byte* ptr, /*!< in: pointer to memory where
written */
roll_ptr_t roll_ptr) /*!< in: roll ptr */
{
#if DATA_ROLL_PTR_LEN != 7
# error "DATA_ROLL_PTR_LEN != 7"
#endif
mach_write_to_7(ptr, roll_ptr);
}
/*****************************************************************//**
Reads a roll ptr from an index page. In case that the roll ptr size
changes in some future version, this function should be used instead of
mach_read_...
@return roll ptr */
UNIV_INLINE
roll_ptr_t
trx_read_roll_ptr(
/*==============*/
const byte* ptr) /*!< in: pointer to memory from where to read */
{
#if DATA_ROLL_PTR_LEN != 7
# error "DATA_ROLL_PTR_LEN != 7"
#endif
return(mach_read_from_7(ptr));
}
#ifndef UNIV_HOTBACKUP
/******************************************************************//**
Gets an undo log page and x-latches it.
@return pointer to page x-latched */
UNIV_INLINE
page_t*
trx_undo_page_get(
/*==============*/
ulint space, /*!< in: space where placed */
ulint zip_size, /*!< in: compressed page size in bytes
or 0 for uncompressed pages */
ulint page_no, /*!< in: page number */
mtr_t* mtr) /*!< in: mtr */
{
buf_block_t* block = buf_page_get(space, zip_size, page_no,
RW_X_LATCH, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
return(buf_block_get_frame(block));
}
/******************************************************************//**
Gets an undo log page and s-latches it.
@return pointer to page s-latched */
UNIV_INLINE
page_t*
trx_undo_page_get_s_latched(
/*========================*/
ulint space, /*!< in: space where placed */
ulint zip_size, /*!< in: compressed page size in bytes
or 0 for uncompressed pages */
ulint page_no, /*!< in: page number */
mtr_t* mtr) /*!< in: mtr */
{
buf_block_t* block = buf_page_get(space, zip_size, page_no,
RW_S_LATCH, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
return(buf_block_get_frame(block));
}
/******************************************************************//**
Returns the start offset of the undo log records of the specified undo
log on the page.
@return start offset */
UNIV_INLINE
ulint
trx_undo_page_get_start(
/*====================*/
page_t* undo_page,/*!< in: undo log page */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
ulint start;
if (page_no == page_get_page_no(undo_page)) {
start = mach_read_from_2(offset + undo_page
+ TRX_UNDO_LOG_START);
} else {
start = TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE;
}
return(start);
}
/******************************************************************//**
Returns the end offset of the undo log records of the specified undo
log on the page.
@return end offset */
UNIV_INLINE
ulint
trx_undo_page_get_end(
/*==================*/
page_t* undo_page,/*!< in: undo log page */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
trx_ulogf_t* log_hdr;
ulint end;
if (page_no == page_get_page_no(undo_page)) {
log_hdr = undo_page + offset;
end = mach_read_from_2(log_hdr + TRX_UNDO_NEXT_LOG);
if (end == 0) {
end = mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
+ TRX_UNDO_PAGE_FREE);
}
} else {
end = mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
+ TRX_UNDO_PAGE_FREE);
}
return(end);
}
/******************************************************************//**
Returns the previous undo record on the page in the specified log, or
NULL if none exists.
@return pointer to record, NULL if none */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_prev_rec(
/*=======================*/
trx_undo_rec_t* rec, /*!< in: undo log record */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
page_t* undo_page;
ulint start;
undo_page = (page_t*) ut_align_down(rec, UNIV_PAGE_SIZE);
start = trx_undo_page_get_start(undo_page, page_no, offset);
if (start + undo_page == rec) {
return(NULL);
}
return(undo_page + mach_read_from_2(rec - 2));
}
/******************************************************************//**
Returns the next undo log record on the page in the specified log, or
NULL if none exists.
@return pointer to record, NULL if none */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_next_rec(
/*=======================*/
trx_undo_rec_t* rec, /*!< in: undo log record */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
page_t* undo_page;
ulint end;
ulint next;
undo_page = (page_t*) ut_align_down(rec, UNIV_PAGE_SIZE);
end = trx_undo_page_get_end(undo_page, page_no, offset);
next = mach_read_from_2(rec);
if (next == end) {
return(NULL);
}
return(undo_page + next);
}
/******************************************************************//**
Returns the last undo record on the page in the specified undo log, or
NULL if none exists.
@return pointer to record, NULL if none */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_last_rec(
/*=======================*/
page_t* undo_page,/*!< in: undo log page */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
ulint start;
ulint end;
start = trx_undo_page_get_start(undo_page, page_no, offset);
end = trx_undo_page_get_end(undo_page, page_no, offset);
if (start == end) {
return(NULL);
}
return(undo_page + mach_read_from_2(undo_page + end - 2));
}
/******************************************************************//**
Returns the first undo record on the page in the specified undo log, or
NULL if none exists.
@return pointer to record, NULL if none */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_first_rec(
/*========================*/
page_t* undo_page,/*!< in: undo log page */
ulint page_no,/*!< in: undo log header page number */
ulint offset) /*!< in: undo log header offset on page */
{
ulint start;
ulint end;
start = trx_undo_page_get_start(undo_page, page_no, offset);
end = trx_undo_page_get_end(undo_page, page_no, offset);
if (start == end) {
return(NULL);
}
return(undo_page + start);
}
#endif /* !UNIV_HOTBACKUP */