[CALCITE-1748] Make CalciteCatalogReader.getSchema extendable to support dynamically load schema tree - getSchema need to be set to protected to allow overriding

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Assignee: Julian Hyde
• Reporter: Chunhui Shi
• Created: 11/Apr/17 07:20
• Updated: 03/Jul/18 04:52
• Resolved: 03/Jul/18 04:52

Description

In system like Drill, there is a need to load partial schema (e.g. for only one storage plugin) only when needed. Since Drill has no way to get a full available schema tree before hand, nor could Drill cache available schema for a storage plugin(e.g. Hive, MongoDB) since the storage plugin may not have notification mechanism to update Schema tree timely.

The proposed fix is to load schema dynamically as shown in https://issues.apache.org/jira/browse/DRILL-5089

To achieve this, we need to make CalciteCatalogReader.getSchema to be protected so it could be overridden by derived class while the derived class can reuse other functionalities in CalciteCatalogReader class
private CalciteSchema getSchema(Iterable<String> schemaNames,
SqlNameMatcher nameMatcher)

Issue Links

• is related to: DRILL-5089 Skip initializing all enabled storage plugins for every query