trx0sys.ic
上传用户:tsgydb
上传日期:2007-04-14
资源大小:10674k
文件大小:9k
- /******************************************************
- Transaction system
- (c) 1996 Innobase Oy
- Created 3/26/1996 Heikki Tuuri
- *******************************************************/
- #include "srv0srv.h"
- #include "trx0trx.h"
- #include "data0type.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 the segment
- header is placed */
- #define TRX_SYS_RSEG_PAGE_NO 4 /* page number where the 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. */
- void
- trx_sys_flush_max_trx_id(void);
- /*==========================*/
- /*******************************************************************
- Checks if a page address is the trx sys header page. */
- UNIV_INLINE
- ibool
- trx_sys_hdr_page(
- /*=============*/
- /* out: TRUE if trx sys header 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. */
- UNIV_INLINE
- trx_rseg_t*
- trx_sys_get_nth_rseg(
- /*=================*/
- /* out: pointer to rseg object, NULL if slot
- not in use */
- 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. */
- UNIV_INLINE
- trx_sysf_t*
- trx_sysf_get(
- /*=========*/
- /* out: pointer to system header, page x-latched. */
- mtr_t* mtr) /* in: mtr */
- {
- trx_sysf_t* header;
- ut_ad(mutex_own(&(kernel_mutex)));
- ut_ad(mtr);
-
- header = TRX_SYS + buf_page_get(TRX_SYS_SPACE, TRX_SYS_PAGE_NO,
- RW_X_LATCH, mtr);
- buf_page_dbg_add_level(header, SYNC_TRX_SYS_HEADER);
- return(header);
- }
- /*********************************************************************
- Gets the space of the nth rollback segment slot in the trx system
- file copy. */
- UNIV_INLINE
- ulint
- trx_sysf_rseg_get_space(
- /*====================*/
- /* out: space id */
- 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. */
- UNIV_INLINE
- ulint
- trx_sysf_rseg_get_page_no(
- /*======================*/
- /* out: page number, FIL_NULL
- if slot unused */
- 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);
- }
- /*********************************************************************
- 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 */
- dulint id) /* in: id */
- {
- ut_ad(DATA_TRX_ID_LEN == 6);
-
- mach_write_to_6(ptr, id);
- }
- /*********************************************************************
- 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_... */
- UNIV_INLINE
- dulint
- trx_read_trx_id(
- /*============*/
- /* out: id */
- byte* ptr) /* in: pointer to memory from where to read */
- {
- ut_ad(DATA_TRX_ID_LEN == 6);
-
- return(mach_read_from_6(ptr));
- }
- /********************************************************************
- Looks for the trx handle with the given id in trx_list. */
- UNIV_INLINE
- trx_t*
- trx_get_on_id(
- /*==========*/
- /* out: the trx handle or NULL if not found */
- dulint 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 (0 == ut_dulint_cmp(trx_id, trx->id)) {
- return(trx);
- }
- trx = UT_LIST_GET_NEXT(trx_list, trx);
- }
- return(NULL);
- }
- /********************************************************************
- 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.) */
- UNIV_INLINE
- dulint
- trx_list_get_min_trx_id(void)
- /*=========================*/
- /* out: the minimum trx id, or trx_sys->max_trx_id
- if the trx list is empty */
- {
- 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. */
- UNIV_INLINE
- ibool
- trx_is_active(
- /*==========*/
- /* out: TRUE if active */
- dulint trx_id) /* in: trx id of the transaction */
- {
- trx_t* trx;
- ut_ad(mutex_own(&(kernel_mutex)));
- if (ut_dulint_cmp(trx_id, trx_list_get_min_trx_id()) < 0) {
- return(FALSE);
- }
- trx = trx_get_on_id(trx_id);
- if (trx && (trx->conc_state == TRX_ACTIVE)) {
-
- return(TRUE);
- }
- return(FALSE);
- }
- /*********************************************************************
- Allocates a new transaction id. */
- UNIV_INLINE
- dulint
- trx_sys_get_new_trx_id(void)
- /*========================*/
- /* out: new, allocated trx id */
- {
- dulint 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 (ut_dulint_get_low(trx_sys->max_trx_id)
- % TRX_SYS_TRX_ID_WRITE_MARGIN == 0) {
- trx_sys_flush_max_trx_id();
- }
-
- id = trx_sys->max_trx_id;
- UT_DULINT_INC(trx_sys->max_trx_id);
- return(id);
- }
- /*********************************************************************
- Allocates a new transaction number. */
- UNIV_INLINE
- dulint
- trx_sys_get_new_trx_no(void)
- /*========================*/
- /* out: new, allocated trx number */
- {
- ut_ad(mutex_own(&kernel_mutex));
- return(trx_sys_get_new_trx_id());
- }