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/*****************************************************************************
Copyright (c) 1996, 2011, 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., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/**************************************************//**
@file include/trx0sys.ic
Transaction system
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "trx0trx.h"
#include "data0type.h"
#ifndef UNIV_HOTBACKUP
# include "srv0srv.h"
# include "mtr0log.h"
/* The typedef for rseg slot in the file copy */
typedef byte trx_sysf_rseg_t;
/* Rollback segment specification slot offsets */
/*-------------------------------------------------------------*/
#define TRX_SYS_RSEG_SPACE 0 /* space where the segment
header is placed; starting with
MySQL/InnoDB 5.1.7, this is
UNIV_UNDEFINED if the slot is unused */
#define TRX_SYS_RSEG_PAGE_NO 4 /* page number where the segment
header is placed; this is FIL_NULL
if the slot is unused */
/*-------------------------------------------------------------*/
/* Size of a rollback segment specification slot */
#define TRX_SYS_RSEG_SLOT_SIZE 8
/*****************************************************************//**
Writes the value of max_trx_id to the file based trx system header. */
UNIV_INTERN
void
trx_sys_flush_max_trx_id(void);
/*==========================*/
/***************************************************************//**
Checks if a page address is the trx sys header page.
@return TRUE if trx sys header page */
UNIV_INLINE
ibool
trx_sys_hdr_page(
/*=============*/
ulint space, /*!< in: space */
ulint page_no)/*!< in: page number */
{
if ((space == TRX_SYS_SPACE) && (page_no == TRX_SYS_PAGE_NO)) {
return(TRUE);
}
return(FALSE);
}
/***************************************************************//**
Gets the pointer in the nth slot of the rseg array.
@return pointer to rseg object, NULL if slot not in use */
UNIV_INLINE
trx_rseg_t*
trx_sys_get_nth_rseg(
/*=================*/
trx_sys_t* sys, /*!< in: trx system */
ulint n) /*!< in: index of slot */
{
ut_ad(mutex_own(&(kernel_mutex)));
ut_ad(n < TRX_SYS_N_RSEGS);
return(sys->rseg_array[n]);
}
/***************************************************************//**
Sets the pointer in the nth slot of the rseg array. */
UNIV_INLINE
void
trx_sys_set_nth_rseg(
/*=================*/
trx_sys_t* sys, /*!< in: trx system */
ulint n, /*!< in: index of slot */
trx_rseg_t* rseg) /*!< in: pointer to rseg object, NULL if slot
not in use */
{
ut_ad(n < TRX_SYS_N_RSEGS);
sys->rseg_array[n] = rseg;
}
/**********************************************************************//**
Gets a pointer to the transaction system header and x-latches its page.
@return pointer to system header, page x-latched. */
UNIV_INLINE
trx_sysf_t*
trx_sysf_get(
/*=========*/
mtr_t* mtr) /*!< in: mtr */
{
buf_block_t* block;
trx_sysf_t* header;
ut_ad(mtr);
block = buf_page_get(TRX_SYS_SPACE, 0, TRX_SYS_PAGE_NO,
RW_X_LATCH, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_SYS_HEADER);
header = TRX_SYS + buf_block_get_frame(block);
return(header);
}
/*****************************************************************//**
Gets the space of the nth rollback segment slot in the trx system
file copy.
@return space id */
UNIV_INLINE
ulint
trx_sysf_rseg_get_space(
/*====================*/
trx_sysf_t* sys_header, /*!< in: trx sys header */
ulint i, /*!< in: slot index == rseg id */
mtr_t* mtr) /*!< in: mtr */
{
ut_ad(mutex_own(&(kernel_mutex)));
ut_ad(sys_header);
ut_ad(i < TRX_SYS_N_RSEGS);
return(mtr_read_ulint(sys_header + TRX_SYS_RSEGS
+ i * TRX_SYS_RSEG_SLOT_SIZE
+ TRX_SYS_RSEG_SPACE, MLOG_4BYTES, mtr));
}
/*****************************************************************//**
Gets the page number of the nth rollback segment slot in the trx system
header.
@return page number, FIL_NULL if slot unused */
UNIV_INLINE
ulint
trx_sysf_rseg_get_page_no(
/*======================*/
trx_sysf_t* sys_header, /*!< in: trx system header */
ulint i, /*!< in: slot index == rseg id */
mtr_t* mtr) /*!< in: mtr */
{
ut_ad(sys_header);
ut_ad(mutex_own(&(kernel_mutex)));
ut_ad(i < TRX_SYS_N_RSEGS);
return(mtr_read_ulint(sys_header + TRX_SYS_RSEGS
+ i * TRX_SYS_RSEG_SLOT_SIZE
+ TRX_SYS_RSEG_PAGE_NO, MLOG_4BYTES, mtr));
}
/*****************************************************************//**
Sets the space id of the nth rollback segment slot in the trx system
file copy. */
UNIV_INLINE
void
trx_sysf_rseg_set_space(
/*====================*/
trx_sysf_t* sys_header, /*!< in: trx sys file copy */
ulint i, /*!< in: slot index == rseg id */
ulint space, /*!< in: space id */
mtr_t* mtr) /*!< in: mtr */
{
ut_ad(mutex_own(&(kernel_mutex)));
ut_ad(sys_header);
ut_ad(i < TRX_SYS_N_RSEGS);
mlog_write_ulint(sys_header + TRX_SYS_RSEGS
+ i * TRX_SYS_RSEG_SLOT_SIZE
+ TRX_SYS_RSEG_SPACE,
space,
MLOG_4BYTES, mtr);
}
/*****************************************************************//**
Sets the page number of the nth rollback segment slot in the trx system
header. */
UNIV_INLINE
void
trx_sysf_rseg_set_page_no(
/*======================*/
trx_sysf_t* sys_header, /*!< in: trx sys header */
ulint i, /*!< in: slot index == rseg id */
ulint page_no, /*!< in: page number, FIL_NULL if the
slot is reset to unused */
mtr_t* mtr) /*!< in: mtr */
{
ut_ad(mutex_own(&(kernel_mutex)));
ut_ad(sys_header);
ut_ad(i < TRX_SYS_N_RSEGS);
mlog_write_ulint(sys_header + TRX_SYS_RSEGS
+ i * TRX_SYS_RSEG_SLOT_SIZE
+ TRX_SYS_RSEG_PAGE_NO,
page_no,
MLOG_4BYTES, mtr);
}
#endif /* !UNIV_HOTBACKUP */
/*****************************************************************//**
Writes a trx id to an index page. In case that the id size changes in
some future version, this function should be used instead of
mach_write_... */
UNIV_INLINE
void
trx_write_trx_id(
/*=============*/
byte* ptr, /*!< in: pointer to memory where written */
trx_id_t id) /*!< in: id */
{
#if DATA_TRX_ID_LEN != 6
# error "DATA_TRX_ID_LEN != 6"
#endif
mach_write_to_6(ptr, id);
}
#ifndef UNIV_HOTBACKUP
/*****************************************************************//**
Reads a trx id from an index page. In case that the id size changes in
some future version, this function should be used instead of
mach_read_...
@return id */
UNIV_INLINE
trx_id_t
trx_read_trx_id(
/*============*/
const byte* ptr) /*!< in: pointer to memory from where to read */
{
#if DATA_TRX_ID_LEN != 6
# error "DATA_TRX_ID_LEN != 6"
#endif
return(mach_read_from_6(ptr));
}
/****************************************************************//**
Looks for the trx handle with the given id in trx_list.
@return the trx handle or NULL if not found */
UNIV_INLINE
trx_t*
trx_get_on_id(
/*==========*/
trx_id_t trx_id) /*!< in: trx id to search for */
{
trx_t* trx;
ut_ad(mutex_own(&(kernel_mutex)));
trx = UT_LIST_GET_FIRST(trx_sys->trx_list);
while (trx != NULL) {
if (trx_id == trx->id) {
return(trx);
}
trx = UT_LIST_GET_NEXT(trx_list, trx);
}
return(NULL);
}
#if defined UNIV_DEBUG || defined UNIV_BLOB_LIGHT_DEBUG
/***********************************************************//**
Assert that a transaction has been recovered.
@return TRUE */
UNIV_INLINE
ibool
trx_assert_recovered(
/*=================*/
trx_id_t trx_id) /*!< in: transaction identifier */
{
trx_t* trx;
mutex_enter(&kernel_mutex);
trx = trx_get_on_id(trx_id);
ut_a(trx);
ut_a(trx->is_recovered);
mutex_exit(&kernel_mutex);
return(TRUE);
}
#endif /* UNIV_DEBUG || UNIV_BLOB_LIGHT_DEBUG */
/****************************************************************//**
Returns the minumum trx id in trx list. This is the smallest id for which
the trx can possibly be active. (But, you must look at the trx->conc_state to
find out if the minimum trx id transaction itself is active, or already
committed.)
@return the minimum trx id, or trx_sys->max_trx_id if the trx list is empty */
UNIV_INLINE
trx_id_t
trx_list_get_min_trx_id(void)
/*=========================*/
{
trx_t* trx;
ut_ad(mutex_own(&(kernel_mutex)));
trx = UT_LIST_GET_LAST(trx_sys->trx_list);
if (trx == NULL) {
return(trx_sys->max_trx_id);
}
return(trx->id);
}
/****************************************************************//**
Checks if a transaction with the given id is active.
@return TRUE if active */
UNIV_INLINE
ibool
trx_is_active(
/*==========*/
trx_id_t trx_id) /*!< in: trx id of the transaction */
{
trx_t* trx;
ut_ad(mutex_own(&(kernel_mutex)));
if (trx_id < trx_list_get_min_trx_id()) {
return(FALSE);
}
if (UNIV_UNLIKELY(trx_id >= trx_sys->max_trx_id)) {
/* There must be corruption: we return TRUE because this
function is only called by lock_clust_rec_some_has_impl()
and row_vers_impl_x_locked_off_kernel() and they have
diagnostic prints in this case */
return(TRUE);
}
trx = trx_get_on_id(trx_id);
if (trx && (trx->conc_state == TRX_ACTIVE
|| trx->conc_state == TRX_PREPARED)) {
return(TRUE);
}
return(FALSE);
}
/*****************************************************************//**
Allocates a new transaction id.
@return new, allocated trx id */
UNIV_INLINE
trx_id_t
trx_sys_get_new_trx_id(void)
/*========================*/
{
trx_id_t id;
ut_ad(mutex_own(&kernel_mutex));
/* VERY important: after the database is started, max_trx_id value is
divisible by TRX_SYS_TRX_ID_WRITE_MARGIN, and the following if
will evaluate to TRUE when this function is first time called,
and the value for trx id will be written to disk-based header!
Thus trx id values will not overlap when the database is
repeatedly started! */
if ((ulint) trx_sys->max_trx_id % TRX_SYS_TRX_ID_WRITE_MARGIN == 0) {
trx_sys_flush_max_trx_id();
}
id = trx_sys->max_trx_id++;
return(id);
}
#endif /* !UNIV_HOTBACKUP */
|