Make "SET @@rocksdb_bulk_load=0" return an error instead of crashing the server

- This is more in line with MariaDB environment
- And help with rocksdb.bulk_load_errors test, too

sql/sql_parse.cc

@@ -4821,6 +4821,7 @@ mysql_execute_command(THD *thd)
       goto error;
     if (!(res= sql_set_variables(thd, lex_var_list, true)))
     {
+      if (!thd->is_error())
         my_ok(thd);
     }
     else

storage/rocksdb/ha_rocksdb.cc

@@ -11493,7 +11493,14 @@ void rocksdb_set_bulk_load(THD *const thd, struct st_mysql_sys_var *const var
       sql_print_error("RocksDB: Error %d finalizing last SST file while "
                       "setting bulk loading variable",
                       rc);
+      /*
+        MariaDB doesn't do the following:
         abort_with_stack_traces();
+        because it doesn't seem a good idea to crash a server when a user makes
+        a mistake.
+        Instead, we return an error to the user. The error has already been
+        produced inside ha_rocksdb::finalize_bulk_load().
+      */
     }
   }
 

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

@@ -14,6 +14,16 @@ INSERT INTO t1 VALUES(1);
 INSERT INTO t1 VALUES(2);
 INSERT INTO t1 VALUES(20);
 INSERT INTO t1 VALUES(21);
+# 
+# In MyRocks, the following statement will intentionally crash the server.
+# In MariaDB, it will cause an error
 SET rocksdb_bulk_load=0;
-ERROR HY000: Lost connection to MySQL server during query
+ERROR HY000: Rows inserted during bulk load must not overlap existing rows
+#
+# Despite the error, bulk load operation is over so the variable value
+# will be 0:
+select @@rocksdb_bulk_load;
+@@rocksdb_bulk_load
+0
+call mtr.add_suppression('finalizing last SST file while setting bulk loading variable');
 DROP TABLE t1;

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

@@ -20,20 +20,17 @@ INSERT INTO t1 VALUES(2);
 INSERT INTO t1 VALUES(20);
 INSERT INTO t1 VALUES(21);
 
-# This last crashes the server (intentionally) because we can't return any
-# error information from a SET <variable>=<value>
---exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
---error 2013
+--echo # 
+--echo # In MyRocks, the following statement will intentionally crash the server.
+--echo # In MariaDB, it will cause an error
+--error ER_OVERLAPPING_KEYS
 SET rocksdb_bulk_load=0;
 
---exec grep "RocksDB: Error 197 finalizing last SST file while setting bulk loading variable" $MYSQLTEST_VARDIR/log/mysqld.1.err | cut -d] -f2
---exec echo "" >$MYSQLTEST_VARDIR/log/mysqld.1.err
+--echo #
+--echo # Despite the error, bulk load operation is over so the variable value
+--echo # will be 0:
+select @@rocksdb_bulk_load;
 
-# restart the crashed server
---exec echo "restart" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
-
-# Make sure the error exists in the .err log and then restart the server
---enable_reconnect
---source include/wait_until_connected_again.inc
+call mtr.add_suppression('finalizing last SST file while setting bulk loading variable');
 
 DROP TABLE t1;