MDEV-9519: Data corruption will happen on the Galera cluster size change

If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.

In the title of the MDEV-9519 it was proposed to ban start slave on a Galera
if master binlog_format = statement and wsrep_auto_increment_control = 1,
but the problem can be solved without such a restriction.

The causes and fixes:

1. We need to improve processing of changing the auto-increment values
after changing the cluster size.

2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.

3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).

https://jira.mariadb.org/browse/MDEV-9519

2 files changed, 100 insertions, 30 deletions

diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 472fb86288f..80ff2e02e13 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -8324,8 +8324,8 @@ no_commit:
 
 		/* We need the upper limit of the col type to check for
 		whether we update the table autoinc counter or not. */
-		col_max_value = innobase_get_int_col_max_value(
-			table->next_number_field);
+		col_max_value =
+			table->next_number_field->get_max_int_value();
 
 		/* Get the value that MySQL attempted to store in the table.*/
 		auto_inc = table->next_number_field->val_uint();
@@ -8402,15 +8402,33 @@ set_max_autoinc:
 				/* This should filter out the negative
 				values set explicitly by the user. */
 				if (auto_inc <= col_max_value) {
-					ut_a(prebuilt->autoinc_increment > 0);
 
 					ulonglong	offset;
 					ulonglong	increment;
 					dberr_t		err;
 
-					offset = prebuilt->autoinc_offset;
-					increment = prebuilt->autoinc_increment;
-
+#ifdef WITH_WSREP
+					/* Applier threads which are processing
+					ROW events and don't go through server
+					level autoinc processing, therefore
+					prebuilt autoinc values don't get
+					properly assigned. Fetch values from
+					server side. */
+					if (wsrep_on(user_thd) &&
+					    wsrep_thd_exec_mode(user_thd) == REPL_RECV)
+					{
+					    wsrep_thd_auto_increment_variables(
+						user_thd, &offset, &increment);
+					}
+					else
+					{
+#endif /* WITH_WSREP */
+					    ut_a(prebuilt->autoinc_increment > 0);
+					    offset = prebuilt->autoinc_offset;
+					    increment = prebuilt->autoinc_increment;
+#ifdef WITH_WSREP
+					}
+#endif /* WITH_WSREP */
 					auto_inc = innobase_next_autoinc(
 						auto_inc,
 						1, increment, offset,
@@ -8925,17 +8943,35 @@ ha_innobase::update_row(
 
 		/* We need the upper limit of the col type to check for
 		whether we update the table autoinc counter or not. */
-		col_max_value = innobase_get_int_col_max_value(
-			table->next_number_field);
+		col_max_value =
+		   table->next_number_field->get_max_int_value();
 
 		if (auto_inc <= col_max_value && auto_inc != 0) {
 
 			ulonglong	offset;
 			ulonglong	increment;
 
-			offset = prebuilt->autoinc_offset;
-			increment = prebuilt->autoinc_increment;
-
+#ifdef WITH_WSREP
+			/* Applier threads which are processing
+			ROW events and don't go through server
+			level autoinc processing, therefore
+			prebuilt autoinc values don't get
+			properly assigned. Fetch values from
+			server side. */
+			if (wsrep_on(user_thd) &&
+			    wsrep_thd_exec_mode(user_thd) == REPL_RECV)
+			{
+			    wsrep_thd_auto_increment_variables(
+				user_thd, &offset, &increment);
+			}
+			else
+			{
+#endif /* WITH_WSREP */
+			    offset = prebuilt->autoinc_offset;
+			    increment = prebuilt->autoinc_increment;
+#ifdef WITH_WSREP
+			}
+#endif /* WITH_WSREP */
 			auto_inc = innobase_next_autoinc(
 				auto_inc, 1, increment, offset, col_max_value);
 
@@ -16040,12 +16076,11 @@ ha_innobase::get_auto_increment(
 				    current, autoinc);
 			if (!wsrep_on(ha_thd()))
 			{
-			current = autoinc - prebuilt->autoinc_increment;
+				current = autoinc - prebuilt->autoinc_increment;
+				current = innobase_next_autoinc(
+					current, 1, increment, offset, col_max_value);
 			}
 
-			current = innobase_next_autoinc(
-				current, 1, increment, offset, col_max_value);
-
 			dict_table_autoinc_initialize(prebuilt->table, current);
 
 			*first_value = current;
diff --git a/storage/xtradb/handler/ha_innodb.cc b/storage/xtradb/handler/ha_innodb.cc
index c9db941b4bf..4ed9f644b45 100644
--- a/storage/xtradb/handler/ha_innodb.cc
+++ b/storage/xtradb/handler/ha_innodb.cc
@@ -8911,8 +8911,8 @@ no_commit:
 
 		/* We need the upper limit of the col type to check for
 		whether we update the table autoinc counter or not. */
-		col_max_value = innobase_get_int_col_max_value(
-			table->next_number_field);
+		col_max_value =
+			table->next_number_field->get_max_int_value();
 
 		/* Get the value that MySQL attempted to store in the table.*/
 		auto_inc = table->next_number_field->val_uint();
@@ -8989,15 +8989,33 @@ set_max_autoinc:
 				/* This should filter out the negative
 				values set explicitly by the user. */
 				if (auto_inc <= col_max_value) {
-					ut_a(prebuilt->autoinc_increment > 0);
 
 					ulonglong	offset;
 					ulonglong	increment;
 					dberr_t		err;
 
-					offset = prebuilt->autoinc_offset;
-					increment = prebuilt->autoinc_increment;
-
+#ifdef WITH_WSREP
+					/* Applier threads which are processing
+					ROW events and don't go through server
+					level autoinc processing, therefore
+					prebuilt autoinc values don't get
+					properly assigned. Fetch values from
+					server side. */
+					if (wsrep_on(user_thd) &&
+					    wsrep_thd_exec_mode(user_thd) == REPL_RECV)
+					{
+					    wsrep_thd_auto_increment_variables(
+						user_thd, &offset, &increment);
+					}
+					else
+					{
+#endif /* WITH_WSREP */
+					    ut_a(prebuilt->autoinc_increment > 0);
+					    offset = prebuilt->autoinc_offset;
+					    increment = prebuilt->autoinc_increment;
+#ifdef WITH_WSREP
+					}
+#endif /* WITH_WSREP */
 					auto_inc = innobase_next_autoinc(
 						auto_inc,
 						1, increment, offset,
@@ -9509,17 +9527,35 @@ ha_innobase::update_row(
 
 		/* We need the upper limit of the col type to check for
 		whether we update the table autoinc counter or not. */
-		col_max_value = innobase_get_int_col_max_value(
-			table->next_number_field);
+		col_max_value =
+			table->next_number_field->get_max_int_value();
 
 		if (auto_inc <= col_max_value && auto_inc != 0) {
 
 			ulonglong	offset;
 			ulonglong	increment;
 
-			offset = prebuilt->autoinc_offset;
-			increment = prebuilt->autoinc_increment;
-
+#ifdef WITH_WSREP
+			/* Applier threads which are processing
+			ROW events and don't go through server
+			level autoinc processing, therefore
+			prebuilt autoinc values don't get
+			properly assigned. Fetch values from
+			server side. */
+			if (wsrep_on(user_thd) &&
+			    wsrep_thd_exec_mode(user_thd) == REPL_RECV)
+			{
+			    wsrep_thd_auto_increment_variables(
+				user_thd, &offset, &increment);
+			}
+			else
+			{
+#endif /* WITH_WSREP */
+			    offset = prebuilt->autoinc_offset;
+			    increment = prebuilt->autoinc_increment;
+#ifdef WITH_WSREP
+			}
+#endif /* WITH_WSREP */
 			auto_inc = innobase_next_autoinc(
 				auto_inc, 1, increment, offset, col_max_value);
 
@@ -16744,12 +16780,11 @@ ha_innobase::get_auto_increment(
 				    current, autoinc);
 			if (!wsrep_on(ha_thd()))
 			{
-			current = autoinc - prebuilt->autoinc_increment;
+				current = autoinc - prebuilt->autoinc_increment;
+				current = innobase_next_autoinc(
+					current, 1, increment, offset, col_max_value);
 			}
 
-			current = innobase_next_autoinc(
-				current, 1, increment, offset, col_max_value);
-
 			dict_table_autoinc_initialize(prebuilt->table, current);
 
 			*first_value = current;