MDEV-25305: MyRocks: Killing server during RESET MASTER can lose last transactions

rocksdb_checkpoint_request() should call FlushWAL(sync=true) (which does
write-out and sync), not just SyncWAL()  (which just syncs without writing
out)
Followup: the test requires debug sync facility

(This is a backport to 10.5)

Author: spetrunia

sql/sql_repl.cc

@@ -3966,6 +3966,8 @@ int reset_master(THD* thd, rpl_gtid *init_state, uint32 init_state_len,
   ret= mysql_bin_log.reset_logs(thd, 1, init_state, init_state_len,
                                 next_log_number);
   repl_semisync_master.after_reset_master();
+  DBUG_EXECUTE_IF("crash_after_reset_master", DBUG_SUICIDE(););
+
   return ret;
 }
 

storage/rocksdb/ha_rocksdb.cc

@@ -4113,7 +4113,7 @@ static int rocksdb_recover(handlerton* hton, XID* xid_list, uint len)
 
 static void rocksdb_checkpoint_request(void *cookie)
 {
-  const rocksdb::Status s= rdb->SyncWAL();
+  const rocksdb::Status s= rdb->FlushWAL(true);
   //TODO: what to do on error?
   if (s.ok())
   {

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

@@ -0,0 +1,19 @@
+#
+# MDEV-25305: MyRocks: Killing server during RESET MASTER can lose last transactions
+#
+set global rocksdb_flush_log_at_trx_commit=1;
+create table t1 (a int, b int, key(a)) engine=rocksdb;
+insert into t1 values (1,1),(2,2);
+select * from t1;
+a	b
+1	1
+2	2
+flush tables;
+set @@debug_dbug="+d,crash_after_reset_master";
+RESET MASTER;
+# Must show the inserted rows:
+select * from t1;
+a	b
+1	1
+2	2
+drop table t1;

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

@@ -0,0 +1,31 @@
+--source include/have_rocksdb.inc
+--source include/have_log_bin.inc
+--source include/have_debug_sync.inc
+
+--echo #
+--echo # MDEV-25305: MyRocks: Killing server during RESET MASTER can lose last transactions
+--echo #
+
+set global rocksdb_flush_log_at_trx_commit=1;
+
+create table t1 (a int, b int, key(a)) engine=rocksdb;
+insert into t1 values (1,1),(2,2);
+select * from t1;
+flush tables;
+
+--write_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+restart
+EOF
+
+set @@debug_dbug="+d,crash_after_reset_master";
+
+--disable_reconnect
+--error 0,2013
+RESET MASTER;
+--enable_reconnect
+--source include/wait_until_connected_again.inc
+--echo # Must show the inserted rows:
+select * from t1;
+
+drop table t1;
+