Fix for Bug # 18828. Return DB_TOO_MANY_CONCURRENT_TRXS when we run out

of UNDO slots in the rollback segment. This is a partial fix since the
MySQL error code requested to properly report the error condition back
to the client has not yet materialized. Currently we have #ifdef'd the
error code translation in ha_innodb.cc. This will have to be changed
as and when MySQl add the new requested code or an equivalent code
that we can then use.

Given the above, currently we will get the old behaviour, not the "fixed"
and intended behaviour.

dict/dict0crea.c

@@ -1195,7 +1195,8 @@ dict_create_or_check_foreign_constraint_tables(void)
 		fprintf(stderr, "InnoDB: error %lu in creation\n",
 			(ulong) error);
 
-		ut_a(error == DB_OUT_OF_FILE_SPACE);
+		ut_a(error == DB_OUT_OF_FILE_SPACE
+		     || error == DB_TOO_MANY_CONCURRENT_TRXS);
 
 		fprintf(stderr,
 			"InnoDB: creation failed\n"

handler/ha_innodb.cc

@@ -627,6 +627,20 @@ convert_error_code_to_mysql(
  		}
 
     		return(HA_ERR_LOCK_TABLE_FULL);
+	} else if (error == DB_TOO_MANY_CONCURRENT_TRXS) {
+
+		/* Once MySQL add the appropriate code to errmsg.txt then
+		we can get rid of this #ifdef. NOTE: The code checked by
+		the #ifdef is the suggested name for the error condition
+		and the actual error code name could very well be different.
+		This will require some monitoring, ie. the status
+		of this request on our part.*/
+#ifdef ER_TOO_MANY_CONCURRENT_TRXS
+		return(ER_TOO_MANY_CONCURRENT_TRXS);
+#else
+		return(HA_ERR_RECORD_FILE_FULL);
+#endif
+
     	} else {
     		return(-1);			// Unknown error
     	}

include/db0err.h

@@ -62,6 +62,11 @@ Created 5/24/1996 Heikki Tuuri
 					lead to a duplicate key in some
 					table */
 
+#define DB_TOO_MANY_CONCURRENT_TRXS 47	/* when InnoDB runs out of the
+					preconfigured undo slots, this can
+					only happen when there are too many
+					concurrent transactions */
+
 /* The following are partial failure codes */
 #define DB_FAIL			1000
 #define DB_OVERFLOW		1001

include/trx0undo.h

@@ -222,13 +222,16 @@ trx_undo_lists_init(
 Assigns an undo log for a transaction. A new undo log is created or a cached
 undo log reused. */
 
-trx_undo_t*
+ulint
 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 */
+				/* out: DB_SUCCESS if undo log assign
+				 * successful, possible error codes are:
+				 * ER_TOO_MANY_CONCURRENT_TRXS
+				 * DB_OUT_OF_FILE_SPAC
+				 * DB_OUT_OF_MEMORY */
+	trx_t*		trx,	/* in: transaction */
+	ulint		type);	/* in: TRX_UNDO_INSERT or TRX_UNDO_UPDATE */
 /**********************************************************************
 Sets the state of the undo log segment at a transaction finish. */
 

row/row0mysql.c

@@ -476,7 +476,8 @@ handle_new_error:
 		/* MySQL will roll back the latest SQL statement */
 	} else if (err == DB_ROW_IS_REFERENCED
 		   || err == DB_NO_REFERENCED_ROW
-		   || err == DB_CANNOT_ADD_CONSTRAINT) {
+		   || err == DB_CANNOT_ADD_CONSTRAINT
+		   || err == DB_TOO_MANY_CONCURRENT_TRXS) {
 		if (savept) {
 			/* Roll back the latest, possibly incomplete
 			insertion or update */

trx/trx0rec.c

@@ -1024,6 +1024,7 @@ trx_undo_report_row_operation(
 	ibool		is_insert;
 	trx_rseg_t*	rseg;
 	mtr_t		mtr;
+	ulint		err		= DB_SUCCESS;
 	mem_heap_t*	heap		= NULL;
 	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
 	ulint*		offsets		= offsets_;
@@ -1035,7 +1036,7 @@ trx_undo_report_row_operation(
 
 		*roll_ptr = ut_dulint_zero;
 
-		return(DB_SUCCESS);
+		return(err);
 	}
 
 	ut_ad(thr);
@@ -1053,7 +1054,7 @@ trx_undo_report_row_operation(
 
 		if (trx->insert_undo == NULL) {
 
-			trx_undo_assign_undo(trx, TRX_UNDO_INSERT);
+			err = trx_undo_assign_undo(trx, TRX_UNDO_INSERT);
 		}
 
 		undo = trx->insert_undo;
@@ -1063,7 +1064,7 @@ trx_undo_report_row_operation(
 
 		if (trx->update_undo == NULL) {
 
-			trx_undo_assign_undo(trx, TRX_UNDO_UPDATE);
+			err = trx_undo_assign_undo(trx, TRX_UNDO_UPDATE);
 
 		}
 
@@ -1071,11 +1072,11 @@ trx_undo_report_row_operation(
 		is_insert = FALSE;
 	}
 
-	if (undo == NULL) {
-		/* Did not succeed: out of space */
+	if (err != DB_SUCCESS) {
+		/* Did not succeed: return the error encountered */
 		mutex_exit(&(trx->undo_mutex));
 
-		return(DB_OUT_OF_FILE_SPACE);
+		return(err);
 	}
 
 	page_no = undo->last_page_no;
@@ -1107,7 +1108,9 @@ trx_undo_report_row_operation(
 		if (offset == 0) {
 			/* The record did not fit on the page. We erase the
 			end segment of the undo log page and write a log
-			record of it to to ensure deterministic contents. */
+			record of it: this is to ensure that in the debug
+			version the replicate page constructed using the log
+			records stays identical to the original page */
 
 			trx_undo_erase_page_end(undo_page, &mtr);
 		}
@@ -1163,7 +1166,7 @@ trx_undo_report_row_operation(
 	if (UNIV_LIKELY_NULL(heap)) {
 		mem_heap_free(heap);
 	}
-	return(DB_SUCCESS);
+	return(err);
 }
 
 /*============== BUILDING PREVIOUS VERSION OF A RECORD ===============*/

trx/trx0undo.c

@@ -373,26 +373,31 @@ trx_undo_page_init(
 /*******************************************************************
 Creates a new undo log segment in file. */
 static
-page_t*
+ulint
 trx_undo_seg_create(
 /*================*/
-				/* out: segment header page x-latched, NULL
-				if no space left */
+				/* out: DB_SUCCESS if page creation OK
+				possible error codes are:
+				DB_TOO_MANY_CONCURRENT_TRXS
+				DB_OUT_OF_FILE_SPACE */
 	trx_rseg_t*	rseg __attribute__((unused)),/* in: rollback segment */
 	trx_rsegf_t*	rseg_hdr,/* in: rollback segment header, page
 				x-latched */
 	ulint		type,	/* in: type of the segment: TRX_UNDO_INSERT or
 				TRX_UNDO_UPDATE */
 	ulint*		id,	/* out: slot index within rseg header */
+	page_t**	undo_page,
+				/* out: segment header page x-latched, NULL
+				if there was an error */
 	mtr_t*		mtr)	/* in: mtr */
 {
 	ulint		slot_no;
 	ulint		space;
-	page_t*		undo_page;
 	trx_upagef_t*	page_hdr;
 	trx_usegf_t*	seg_hdr;
 	ulint		n_reserved;
 	ibool		success;
+	ulint		err = DB_SUCCESS;
 
 	ut_ad(mtr && id && rseg_hdr);
 	ut_ad(mutex_own(&(rseg->mutex)));
@@ -410,7 +415,7 @@ trx_undo_seg_create(
 			"InnoDB: many active transactions"
 			" running concurrently?\n");
 
-		return(NULL);
+		return(DB_TOO_MANY_CONCURRENT_TRXS);
 	}
 
 	space = buf_frame_get_space_id(rseg_hdr);
@@ -419,30 +424,30 @@ trx_undo_seg_create(
 					   mtr);
 	if (!success) {
 
-		return(NULL);
+		return(DB_OUT_OF_FILE_SPACE);
 	}
 
 	/* Allocate a new file segment for the undo log */
-	undo_page = fseg_create_general(space, 0,
+	*undo_page = fseg_create_general(space, 0,
 					TRX_UNDO_SEG_HDR
 					+ TRX_UNDO_FSEG_HEADER, TRUE, mtr);
 
 	fil_space_release_free_extents(space, n_reserved);
 
-	if (undo_page == NULL) {
+	if (*undo_page == NULL) {
 		/* No space left */
 
-		return(NULL);
+		return(DB_OUT_OF_FILE_SPACE);
 	}
 
 #ifdef UNIV_SYNC_DEBUG
-	buf_page_dbg_add_level(undo_page, SYNC_TRX_UNDO_PAGE);
+	buf_page_dbg_add_level(*undo_page, SYNC_TRX_UNDO_PAGE);
 #endif /* UNIV_SYNC_DEBUG */
 
-	page_hdr = undo_page + TRX_UNDO_PAGE_HDR;
-	seg_hdr = undo_page + TRX_UNDO_SEG_HDR;
+	page_hdr = *undo_page + TRX_UNDO_PAGE_HDR;
+	seg_hdr = *undo_page + TRX_UNDO_SEG_HDR;
 
-	trx_undo_page_init(undo_page, type, mtr);
+	trx_undo_page_init(*undo_page, type, mtr);
 
 	mlog_write_ulint(page_hdr + TRX_UNDO_PAGE_FREE,
 			 TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE,
@@ -456,10 +461,11 @@ trx_undo_seg_create(
 		      page_hdr + TRX_UNDO_PAGE_NODE, mtr);
 
 	trx_rsegf_set_nth_undo(rseg_hdr, slot_no,
-			       buf_frame_get_page_no(undo_page), mtr);
+				buf_frame_get_page_no(*undo_page), mtr);
+
 	*id = slot_no;
 
-	return(undo_page);
+	return(err);
 }
 
 /**************************************************************************
@@ -1387,6 +1393,11 @@ trx_undo_mem_create(
 
 	undo = mem_alloc(sizeof(trx_undo_t));
 
+	if (undo == NULL) {
+
+		return NULL;
+	}
+
 	undo->id = id;
 	undo->type = type;
 	undo->state = TRX_UNDO_ACTIVE;
@@ -1464,11 +1475,15 @@ trx_undo_mem_free(
 /**************************************************************************
 Creates a new undo log. */
 static
-trx_undo_t*
+ulint
 trx_undo_create(
 /*============*/
-				/* out: undo log object, NULL if did not
-				succeed: out of space */
+				/* out: DB_SUCCESS if successful in creating
+				the new undo lob object, possible error
+				codes are: 
+				DB_TOO_MANY_CONCURRENT_TRXS
+				DB_OUT_OF_FILE_SPACE 
+				DB_OUT_OF_MEMORY*/
 	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
@@ -1476,34 +1491,37 @@ trx_undo_create(
 	dulint		trx_id,	/* in: id of the trx for which the undo log
 				is created */
 	XID*		xid,	/* in: X/Open transaction identification*/
+	trx_undo_t**	undo,	/* out: the new undo log object, undefined
+				 * if did not succeed */
 	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;
+	ulint		err;
 
 	ut_ad(mutex_own(&(rseg->mutex)));
 
 	if (rseg->curr_size == rseg->max_size) {
 
-		return(NULL);
+		return(DB_OUT_OF_FILE_SPACE);
 	}
 
 	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);
+	err = trx_undo_seg_create(rseg, rseg_header, type, &id,
+							&undo_page, mtr);
 
-	if (undo_page == NULL) {
+	if (err != DB_SUCCESS) {
 		/* Did not succeed */
 
 		rseg->curr_size--;
 
-		return(NULL);
+		return(err);
 	}
 
 	page_no = buf_frame_get_page_no(undo_page);
@@ -1515,9 +1533,14 @@ trx_undo_create(
 						  undo_page + offset, mtr);
 	}
 
-	undo = trx_undo_mem_create(rseg, id, type, trx_id, xid,
+	*undo = trx_undo_mem_create(rseg, id, type, trx_id, xid,
 				   page_no, offset);
-	return(undo);
+	if (*undo == NULL) {
+
+		err = DB_OUT_OF_MEMORY;
+	}
+
+	return(err);
 }
 
 /*================ UNDO LOG ASSIGNMENT AND CLEANUP =====================*/
@@ -1634,17 +1657,20 @@ trx_undo_mark_as_dict_operation(
 Assigns an undo log for a transaction. A new undo log is created or a cached
 undo log reused. */
 
-trx_undo_t*
+ulint
 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 */
+				/* out: DB_SUCCESS if undo log assign
+				successful, possible error codes are:
+				DD_TOO_MANY_CONCURRENT_TRXS
+				DB_OUT_OF_FILE_SPACE DB_OUT_OF_MEMORY*/
+	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;
+	ulint		err = DB_SUCCESS;
 
 	ut_ad(trx);
 	ut_ad(trx->rseg);
@@ -1662,15 +1688,11 @@ trx_undo_assign_undo(
 	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 */
+		err = trx_undo_create(trx, rseg, type, trx->id, &trx->xid,
+								&undo, &mtr);
+		if (err != DB_SUCCESS) {
 
-			mutex_exit(&(rseg->mutex));
-			mtr_commit(&mtr);
-
-			return(NULL);
+			goto func_exit;
 		}
 	}
 
@@ -1688,10 +1710,11 @@ trx_undo_assign_undo(
 		trx_undo_mark_as_dict_operation(trx, undo, &mtr);
 	}
 
+func_exit:
 	mutex_exit(&(rseg->mutex));
 	mtr_commit(&mtr);
 
-	return(undo);
+	return err;
 }
 
 /**********************************************************************