[CALCITE-1101] Extend Schema SPI to provide materialized views

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Julian Hyde
• Created: 25/Feb/16 20:34
• Updated: 22/Feb/19 01:20

Description

Currently the way to get materialized views is via MaterializationService, but it would be simpler to get them from a new method Schema.getMaterializedViews().

Some thoughts:

• The method should return materialized views not just in the current schema, and therefore
• The method should be filtered by Table (or Tables)
• The objects returned can not include RelNode (RelNode can only be created in the context of a statement, and the Schema is created before the first statement; furthermore, holding onto RelNode would be a resource leak). But they should provide the means to create a RelNode (given sufficient context).
• Maybe the objects returned indicate something about the mapping

Taking all this, we get

List<Foo> getMaterializedViews(Table... tables);

class Foo {
  public final Table view;
  public final List<Table> referencedTables;
  public final TileKey tileKey; // may be null
  public final String sql; // may be null; for information only

  public RelNode rel(Context context);
}

Maybe we can obsolete CalciteSchema.getTableBySql.

Cc maryannxue, jamestaylor.