Merge 10.1 into 10.2

For running the Galera tests, the variable my_disable_leak_check
was set to true in order to avoid assertions due to memory leaks
at shutdown.

Some adjustments due to MDEV-13625 (merge InnoDB tests from MySQL 5.6)
were performed. The most notable behaviour changes from 10.0 and 10.1
are the following:

* innodb.innodb-table-online: adjustments for the DROP COLUMN
behaviour change (MDEV-11114, MDEV-13613)

* innodb.innodb-index-online-fk: the removal of a (1,NULL) record
from the result; originally removed in MySQL 5.7 in the
Oracle Bug #16244691 fix
https://github.com/mysql/mysql-server/commit/377774689bf6a16af74182753fe950d514c2c6dd

* innodb.create-index-debug: disabled due to MDEV-13680
(the MySQL Bug #77497 fix was not merged from 5.6 to 5.7.10)

* innodb.innodb-alter-autoinc: MariaDB 10.2 behaves like MySQL 5.6/5.7,
while MariaDB 10.0 and 10.1 assign different values when
auto_increment_increment or auto_increment_offset are used.
Also MySQL 5.6/5.7 exhibit different behaviour between
LGORITHM=INPLACE and ALGORITHM=COPY, so something needs to be tested
and fixed in both MariaDB 10.0 and 10.2.

* innodb.innodb-wl5980-alter: disabled because it would trigger an
InnoDB assertion failure (MDEV-13668 may need additional effort in 10.2)

1 files changed, 32 insertions, 17 deletions

diff --git a/sql/wsrep_var.cc b/sql/wsrep_var.cc
index b34fdf8b7ed..41a8f6c7eb0 100644
--- a/sql/wsrep_var.cc
+++ b/sql/wsrep_var.cc
@@ -27,6 +27,8 @@
 #include <cstdlib>
 
 
+static long wsrep_prev_slave_threads = wsrep_slave_threads;
+
 int wsrep_init_vars()
 {
   wsrep_provider        = my_strdup(WSREP_NONE, MYF(MY_WME));
@@ -49,12 +51,23 @@ bool wsrep_on_update (sys_var *self, THD* thd, enum_var_type var_type)
   return false;
 }
 
-bool wsrep_causal_reads_update (SV *sv)
+bool wsrep_causal_reads_update (sys_var *self, THD* thd, enum_var_type var_type)
 {
-  if (sv->wsrep_causal_reads) {
-    sv->wsrep_sync_wait |= WSREP_SYNC_WAIT_BEFORE_READ;
+  // global setting should not affect session setting.
+  // if (var_type == OPT_GLOBAL) {
+  //   thd->variables.wsrep_causal_reads = global_system_variables.wsrep_causal_reads;
+  // }
+  if (thd->variables.wsrep_causal_reads) {
+    thd->variables.wsrep_sync_wait |= WSREP_SYNC_WAIT_BEFORE_READ;
+  } else {
+    thd->variables.wsrep_sync_wait &= ~WSREP_SYNC_WAIT_BEFORE_READ;
+  }
+
+  // update global settings too.
+  if (global_system_variables.wsrep_causal_reads) {
+      global_system_variables.wsrep_sync_wait |= WSREP_SYNC_WAIT_BEFORE_READ;
   } else {
-    sv->wsrep_sync_wait &= ~WSREP_SYNC_WAIT_BEFORE_READ;
+      global_system_variables.wsrep_sync_wait &= ~WSREP_SYNC_WAIT_BEFORE_READ;
   }
 
   return false;
@@ -62,12 +75,17 @@ bool wsrep_causal_reads_update (SV *sv)
 
 bool wsrep_sync_wait_update (sys_var* self, THD* thd, enum_var_type var_type)
 {
-  if (var_type == OPT_GLOBAL)
-    global_system_variables.wsrep_causal_reads =
-      MY_TEST(global_system_variables.wsrep_sync_wait & WSREP_SYNC_WAIT_BEFORE_READ);
-  else
-    thd->variables.wsrep_causal_reads =
-      MY_TEST(thd->variables.wsrep_sync_wait & WSREP_SYNC_WAIT_BEFORE_READ);
+  // global setting should not affect session setting.
+  // if (var_type == OPT_GLOBAL) {
+  //   thd->variables.wsrep_sync_wait = global_system_variables.wsrep_sync_wait;
+  // }
+  thd->variables.wsrep_causal_reads = thd->variables.wsrep_sync_wait &
+          WSREP_SYNC_WAIT_BEFORE_READ;
+
+  // update global settings too
+  global_system_variables.wsrep_causal_reads = global_system_variables.wsrep_sync_wait &
+          WSREP_SYNC_WAIT_BEFORE_READ;
+
   return false;
 }
 
@@ -528,18 +546,15 @@ void wsrep_node_address_init (const char* value)
   wsrep_node_address = (value) ? my_strdup(value, MYF(0)) : NULL;
 }
 
-bool wsrep_slave_threads_check (sys_var *self, THD* thd, set_var* var)
+static void wsrep_slave_count_change_update ()
 {
-  mysql_mutex_lock(&LOCK_wsrep_slave_threads);
-  wsrep_slave_count_change += (var->save_result.ulonglong_value -
-                               wsrep_slave_threads);
-  mysql_mutex_unlock(&LOCK_wsrep_slave_threads);
-
-  return 0;
+  wsrep_slave_count_change += (wsrep_slave_threads - wsrep_prev_slave_threads);
+  wsrep_prev_slave_threads = wsrep_slave_threads;
 }
 
 bool wsrep_slave_threads_update (sys_var *self, THD* thd, enum_var_type type)
 {
+  wsrep_slave_count_change_update();
   if (wsrep_slave_count_change > 0)
   {
     wsrep_create_appliers(wsrep_slave_count_change);