Software Environment:

• OpenLooKeng version (source or binary):0.1.0

• OS platform & distribution (eg., Linux Ubuntu 16.04):Linux Ubuntu 18.04

• Java version:1.8.0_201

Describe the current behavior

Currently, when we have a data center catalog, and issue a query, openLooKeng will fetch the catalogs from remote data center, the implement code is in the PageSourceManager class, when create a PageSource it will load catalogs from remote data center once. One remote task will create several PagesSource, so will load catalogs several times, this operation is unnecessary, it only need to load catalogs once when executing a remote task.

Describe the expected behavior

When executing a remote task, it only need to load catalogs once.

Steps to reproduce the issue

1. create a data center catalog
2. issue a query
3. will see there are several query catalogs in the remote openLooKeng cluster.

Related log/screenshots

Special notes for this issue