trx0undo.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

static
void
trx_undo_mem_init_for_reuse(
/*========================*/
	trx_undo_t*	undo,	/* in: undo log to init */
	dulint		trx_id,	/* in: id of the trx for which the undo log
				is created */
	XID*		xid,	/* in: X/Open XA transaction identification*/
	ulint		offset)	/* in: undo log header byte offset on page */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&((undo->rseg)->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	
 	if (undo->id >= TRX_RSEG_N_SLOTS) {
		fprintf(stderr, "InnoDB: Error: undo->id is %lu\n",
			(ulong) undo->id);

		mem_analyze_corruption((byte*)undo);
		ut_error;
	}

	undo->state = TRX_UNDO_ACTIVE;
	undo->del_marks = FALSE;
	undo->trx_id = trx_id;
	undo->xid = *xid;

	undo->dict_operation = FALSE;

	undo->hdr_offset = offset;
	undo->empty = TRUE;
}

/************************************************************************
Frees an undo log memory copy. */
static
void
trx_undo_mem_free(
/*==============*/
	trx_undo_t*	undo)	/* in: the undo object to be freed */
{
	if (undo->id >= TRX_RSEG_N_SLOTS) {
		fprintf(stderr,
		"InnoDB: Error: undo->id is %lu\n", (ulong) undo->id);
		ut_error;
	}

	mem_free(undo);
}

/**************************************************************************
Creates a new undo log. */
static
trx_undo_t*
trx_undo_create(
/*============*/
				/* out: undo log object, NULL if did not
				succeed: out of space */
	trx_t*		trx,	/* in: transaction */
	trx_rseg_t*	rseg,	/* in: rollback segment memory copy */
	ulint		type,	/* in: type of the log: TRX_UNDO_INSERT or
				TRX_UNDO_UPDATE */
	dulint		trx_id,	/* in: id of the trx for which the undo log
				is created */ 
	XID*		xid,	/* in: X/Open transaction identification*/
	mtr_t*		mtr)	/* in: mtr */
{
	trx_rsegf_t*	rseg_header;
	ulint		page_no;
	ulint		offset;
	ulint		id;
	trx_undo_t*	undo;
	page_t*		undo_page;
	
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(rseg->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	if (rseg->curr_size == rseg->max_size) {

		return(NULL);
	}

	rseg->curr_size++;

	rseg_header = trx_rsegf_get(rseg->space, rseg->page_no, mtr);

	undo_page = trx_undo_seg_create(rseg, rseg_header, type, &id, mtr);
	
	if (undo_page == NULL) {
		/* Did not succeed */

		rseg->curr_size--;

		return(NULL);
	}

	page_no = buf_frame_get_page_no(undo_page);
	
	offset = trx_undo_header_create(undo_page, trx_id, mtr);

	if (trx->support_xa) {
		trx_undo_header_add_space_for_xid(undo_page,
					undo_page + offset, mtr);
	}

	undo = trx_undo_mem_create(rseg, id, type, trx_id, xid,
							page_no, offset);
	return(undo);
}

/*================ UNDO LOG ASSIGNMENT AND CLEANUP =====================*/

/************************************************************************
Reuses a cached undo log. */
static
trx_undo_t*
trx_undo_reuse_cached(
/*==================*/
				/* out: the undo log memory object, NULL if
				none cached */
	trx_t*		trx,	/* in: transaction */
	trx_rseg_t*	rseg,	/* in: rollback segment memory object */
	ulint		type,	/* in: type of the log: TRX_UNDO_INSERT or
				TRX_UNDO_UPDATE */
	dulint		trx_id,	/* in: id of the trx for which the undo log
				is used */	
	XID*		xid,	/* in: X/Open XA transaction identification */
	mtr_t*		mtr)	/* in: mtr */
{
	trx_undo_t*	undo;
	page_t*		undo_page;
	ulint		offset;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(rseg->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	if (type == TRX_UNDO_INSERT) {

		undo = UT_LIST_GET_FIRST(rseg->insert_undo_cached);
		if (undo == NULL) {

			return(NULL);
		}

		UT_LIST_REMOVE(undo_list, rseg->insert_undo_cached, undo);
	} else {
		ut_ad(type == TRX_UNDO_UPDATE);

		undo = UT_LIST_GET_FIRST(rseg->update_undo_cached);
		if (undo == NULL) {

			return(NULL);
		}

		UT_LIST_REMOVE(undo_list, rseg->update_undo_cached, undo);
	}

	ut_ad(undo->size == 1);

	if (undo->id >= TRX_RSEG_N_SLOTS) {
		fprintf(stderr, "InnoDB: Error: undo->id is %lu\n",
			(ulong) undo->id);
		mem_analyze_corruption((byte*)undo);
		ut_error;
	}

	undo_page = trx_undo_page_get(undo->space, undo->hdr_page_no, mtr);

	if (type == TRX_UNDO_INSERT) {
		offset = trx_undo_insert_header_reuse(undo_page, trx_id, mtr);
		
		if (trx->support_xa) {
			trx_undo_header_add_space_for_xid(undo_page,
						undo_page + offset, mtr);
		}
	} else {
		ut_a(mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
					+ TRX_UNDO_PAGE_TYPE)
						== TRX_UNDO_UPDATE);

		offset = trx_undo_header_create(undo_page, trx_id, mtr);

		if (trx->support_xa) {
			trx_undo_header_add_space_for_xid(undo_page,
						undo_page + offset, mtr);
		}
	}
	
	trx_undo_mem_init_for_reuse(undo, trx_id, xid, offset);

	return(undo);
}

/**************************************************************************
Marks an undo log header as a header of a data dictionary operation
transaction. */
static
void
trx_undo_mark_as_dict_operation(
/*============================*/
	trx_t*		trx,	/* in: dict op transaction */
	trx_undo_t*	undo,	/* in: assigned undo log */
	mtr_t*		mtr)	/* in: mtr */
{
	page_t*	hdr_page;

	ut_a(trx->dict_operation);
	
	hdr_page = trx_undo_page_get(undo->space, undo->hdr_page_no, mtr);

	mlog_write_ulint(hdr_page + undo->hdr_offset + 
				TRX_UNDO_DICT_TRANS,
				trx->dict_operation, MLOG_1BYTE, mtr);

	mlog_write_dulint(hdr_page + undo->hdr_offset + TRX_UNDO_TABLE_ID,
			trx->table_id, mtr);	

	undo->dict_operation = trx->dict_operation;
	undo->table_id = trx->table_id;
}

/**************************************************************************
Assigns an undo log for a transaction. A new undo log is created or a cached
undo log reused. */

trx_undo_t*
trx_undo_assign_undo(
/*=================*/
			/* out: the undo log, NULL if did not succeed: out of
			space */
	trx_t*	trx,	/* in: transaction */
	ulint	type)	/* in: TRX_UNDO_INSERT or TRX_UNDO_UPDATE */
{
	trx_rseg_t*	rseg;
	trx_undo_t*	undo;
	mtr_t		mtr;

	ut_ad(trx);
	ut_ad(trx->rseg);

	rseg = trx->rseg;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(trx->undo_mutex)));
#endif /* UNIV_SYNC_DEBUG */

	mtr_start(&mtr);

#ifdef UNIV_SYNC_DEBUG
	ut_ad(!mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
	mutex_enter(&(rseg->mutex));

	undo = trx_undo_reuse_cached(trx, rseg, type, trx->id, &trx->xid,
									&mtr);
	if (undo == NULL) {
		undo = trx_undo_create(trx, rseg, type, trx->id, &trx->xid,
									&mtr);
		if (undo == NULL) {
			/* Did not succeed */

			mutex_exit(&(rseg->mutex));
			mtr_commit(&mtr);

			return(NULL);
		}
	}

	if (type == TRX_UNDO_INSERT) {
		UT_LIST_ADD_FIRST(undo_list, rseg->insert_undo_list, undo);
		ut_ad(trx->insert_undo == NULL);
		trx->insert_undo = undo;
	} else {
		UT_LIST_ADD_FIRST(undo_list, rseg->update_undo_list, undo);
		ut_ad(trx->update_undo == NULL);
		trx->update_undo = undo;
	}

	if (trx->dict_operation) {
		trx_undo_mark_as_dict_operation(trx, undo, &mtr);
	}

	mutex_exit(&(rseg->mutex));
	mtr_commit(&mtr);

	return(undo);
}

/**********************************************************************
Sets the state of the undo log segment at a transaction finish. */

page_t*
trx_undo_set_state_at_finish(
/*=========================*/
				/* out: undo log segment header page,
				x-latched */
	trx_t*		trx __attribute__((unused)), /* in: transaction */
	trx_undo_t*	undo,	/* in: undo log memory copy */
	mtr_t*		mtr)	/* in: mtr */
{
	trx_usegf_t*	seg_hdr;
	trx_upagef_t*	page_hdr;
	page_t*		undo_page;
	ulint		state;
	
	ut_ad(trx && undo && mtr);

	if (undo->id >= TRX_RSEG_N_SLOTS) {
		fprintf(stderr, "InnoDB: Error: undo->id is %lu\n",
			(ulong) undo->id);
		mem_analyze_corruption((byte*)undo);
		ut_error;
	}

	undo_page = trx_undo_page_get(undo->space, undo->hdr_page_no, mtr);

	seg_hdr = undo_page + TRX_UNDO_SEG_HDR;
	page_hdr = undo_page + TRX_UNDO_PAGE_HDR;

	if (undo->size == 1 && mach_read_from_2(page_hdr + TRX_UNDO_PAGE_FREE)
						< TRX_UNDO_PAGE_REUSE_LIMIT) {
		state = TRX_UNDO_CACHED;

	} else if (undo->type == TRX_UNDO_INSERT) {

		state = TRX_UNDO_TO_FREE;
	} else {
		state = TRX_UNDO_TO_PURGE;
	}

	undo->state = state;
		   
	mlog_write_ulint(seg_hdr + TRX_UNDO_STATE, state, MLOG_2BYTES, mtr);

	return(undo_page);
}

/**********************************************************************
Sets the state of the undo log segment at a transaction prepare. */

page_t*
trx_undo_set_state_at_prepare(
/*==========================*/
				/* out: undo log segment header page,
				x-latched */
	trx_t*		trx,	/* in: transaction */
	trx_undo_t*	undo,	/* in: undo log memory copy */
	mtr_t*		mtr)	/* in: mtr */
{
	trx_usegf_t*	seg_hdr;
	trx_upagef_t*	page_hdr;
	trx_ulogf_t*	undo_header;
	page_t*		undo_page;
	ulint		offset;
	
	ut_ad(trx && undo && mtr);

	if (undo->id >= TRX_RSEG_N_SLOTS) {
		fprintf(stderr, "InnoDB: Error: undo->id is %lu\n",
			(ulong) undo->id);
		mem_analyze_corruption((byte*)undo);
		ut_error;
	}

	undo_page = trx_undo_page_get(undo->space, undo->hdr_page_no, mtr);

	seg_hdr = undo_page + TRX_UNDO_SEG_HDR;
	page_hdr = undo_page + TRX_UNDO_PAGE_HDR;

	/*------------------------------*/
	undo->state = TRX_UNDO_PREPARED;
	undo->xid   = trx->xid;
	/*------------------------------*/
		   
	mlog_write_ulint(seg_hdr + TRX_UNDO_STATE, undo->state, 
			 MLOG_2BYTES, mtr);

	offset = mach_read_from_2(seg_hdr + TRX_UNDO_LAST_LOG);
        undo_header = undo_page + offset;

	mlog_write_ulint(undo_header + TRX_UNDO_XID_EXISTS,
					TRUE, MLOG_1BYTE, mtr);

	trx_undo_write_xid(undo_header, &undo->xid, mtr);	

	return(undo_page);
}

/**************************************************************************
Adds the update undo log header as the first in the history list, and
frees the memory object, or puts it to the list of cached update undo log
segments. */

void
trx_undo_update_cleanup(
/*====================*/
	trx_t*	trx,		/* in: trx owning the update undo log */
	page_t*	undo_page,	/* in: update undo log header page,
				x-latched */
	mtr_t*	mtr)		/* in: mtr */
{
	trx_rseg_t*	rseg;
	trx_undo_t*	undo;
	
	undo = trx->update_undo;
	rseg = trx->rseg;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(rseg->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	trx_purge_add_update_undo_to_history(trx, undo_page, mtr);

	UT_LIST_REMOVE(undo_list, rseg->update_undo_list, undo);

	trx->update_undo = NULL;

	if (undo->state == TRX_UNDO_CACHED) {

		UT_LIST_ADD_FIRST(undo_list, rseg->update_undo_cached, undo);
	} else {
		ut_ad(undo->state == TRX_UNDO_TO_PURGE);

		trx_undo_mem_free(undo);
	}
}

/**********************************************************************
Frees or caches an insert undo log after a transaction commit or rollback.
Knowledge of inserts is not needed after a commit or rollback, therefore
the data can be discarded. */

void
trx_undo_insert_cleanup(
/*====================*/
	trx_t*	trx)	/* in: transaction handle */
{
	trx_undo_t*	undo;
	trx_rseg_t*	rseg;
	
	undo = trx->insert_undo;
	ut_ad(undo);

	rseg = trx->rseg;

	mutex_enter(&(rseg->mutex));

	UT_LIST_REMOVE(undo_list, rseg->insert_undo_list, undo);
	trx->insert_undo = NULL;

	if (undo->state == TRX_UNDO_CACHED) {

		UT_LIST_ADD_FIRST(undo_list, rseg->insert_undo_cached, undo);
	} else {
		ut_ad(undo->state == TRX_UNDO_TO_FREE);

		/* Delete first the undo log segment in the file */

		mutex_exit(&(rseg->mutex));

		trx_undo_seg_free(undo);

		mutex_enter(&(rseg->mutex));

		ut_ad(rseg->curr_size > undo->size);
	
		rseg->curr_size -= undo->size;

		trx_undo_mem_free(undo);
	}
	
	mutex_exit(&(rseg->mutex));
}