Exception occurred postgre backend execute DDL statement in transaction

[Gii16]

Bug Report

Which version of ShardingSphere did you use?

5.4.0

Which project did you use? ShardingSphere-JDBC or ShardingSphere-Proxy?

ShardingSphere-Proxy

Expected behavior

I use a SQL client to send command to ShardingSphere-Proxy and forward to postgre DB. I execute DDL statement in transaction.

Statements as follow:
1.begin;
2.create table table_name;
3.create index on table_name;
4.commit;

Actual behavior

There is a null point exception. I lost log in server so I can't display it. However, I know the reason.

Reason analyze (If you can)

Get an exception while execute refreshMetaData() in DatabaseConnector#doExecute(). Cause the table created in step 2 can not be seen in step3.
SchemaMetaDataLoaderEngine#load will get another connection to get meta data. There is an isolation between two connections.

Steps to reproduce the behavior, such as: SQL to execute, sharding rule configuration, when exception occur etc.

Example codes for reproduce this issue (such as a github link).