Fix rocksdb.autoinc_vars_thread test

storage/rocksdb/ha_rocksdb.cc

@@ -12178,6 +12178,7 @@ void ha_rocksdb::get_auto_increment(ulonglong off, ulonglong inc,
     an actual reserve of some values might be a better solution.
    */
   DEBUG_SYNC(ha_thd(), "rocksdb.autoinc_vars");
+  DEBUG_SYNC(ha_thd(), "rocksdb.autoinc_vars2");
 
   if (off > inc) {
     off = 1;

storage/rocksdb/mysql-test/rocksdb/r/autoinc_vars_thread.result

@@ -12,17 +12,18 @@ SET auto_increment_increment = 2;
 SET auto_increment_offset = 1;
 connect  con3, localhost, root,,;
 connection con1;
+SET debug_sync='rocksdb.autoinc_vars2 SIGNAL go2';
 SET debug_sync='rocksdb.autoinc_vars SIGNAL parked1 WAIT_FOR go1';
 INSERT INTO t1 VALUES(NULL);
+connection default;
+SET debug_sync='now WAIT_FOR parked1';
 connection con2;
 SET debug_sync='rocksdb.autoinc_vars SIGNAL parked2 WAIT_FOR go2';
 INSERT INTO t1 VALUES(NULL);
 connection default;
-SET debug_sync='now WAIT_FOR parked1';
 SET debug_sync='now WAIT_FOR parked2';
 SET debug_sync='now SIGNAL go1';
 connection con3;
-SET debug_sync='now SIGNAL go2';
 connection default;
 connection con1;
 connection con2;

storage/rocksdb/mysql-test/rocksdb/t/autoinc_vars_thread.test

@@ -23,22 +23,28 @@ connect (con3, localhost, root,,);
 
 # Start each thread on an insert that will block waiting for a signal
 connection con1;
+SET debug_sync='rocksdb.autoinc_vars2 SIGNAL go2';
 SET debug_sync='rocksdb.autoinc_vars SIGNAL parked1 WAIT_FOR go1';
 send INSERT INTO t1 VALUES(NULL);
 
+connection default;
+SET debug_sync='now WAIT_FOR parked1';
+
 connection con2;
 SET debug_sync='rocksdb.autoinc_vars SIGNAL parked2 WAIT_FOR go2';
 send INSERT INTO t1 VALUES(NULL);
 
 # Wait for both threads to be at debug_sync point
 connection default;
-SET debug_sync='now WAIT_FOR parked1';
 SET debug_sync='now WAIT_FOR parked2';
 
+
 # Signal both threads to continue
+# (In MariaDB, we signal one of them which continues and signals the other)
 send SET debug_sync='now SIGNAL go1';
 connection con3;
-SET debug_sync='now SIGNAL go2';
+# MariaDB: do nothing here
+
 connection default;
 reap;