[jira] [Commented] (CALCITE-761) Pre-populated materializations

["Maryann Xue (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-761?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14594838#comment-14594838 ] 

Maryann Xue commented on CALCITE-761:
-------------------------------------

{code}
    final CalciteConnection connection =
        CalciteMetaImpl.connect(schema.root(), null);
    CalciteSchema.TableEntry tableEntry = schema.getTableBySql(viewSql);
    RelDataType rowType = null;
    if (tableEntry == null) {
      Table table = tableFactory.createTable(schema, viewSql, viewSchemaPath);
      final String tableName = Schemas.uniqueTableName(schema,
          Util.first(suggestedTableName, "m"));
      tableEntry = schema.add(tableName, table, ImmutableList.of(viewSql));
      Hook.CREATE_MATERIALIZATION.run(tableName);
      rowType = table.getRowType(connection.getTypeFactory());
    }
{code}

In the above code from MaterializationService.defineMaterialization(), looks like it tries to get a TableEntry by calling schema.getTableBySql() and if this returns now it will start to create one.
After I made the change below (just a temporary fix I guess), things worked out fine for me:

{code}
@@ -116,7 +116,10 @@ public MaterializationKey defineMaterialization(final CalciteSchema schema,
 
     final CalciteConnection connection =
         CalciteMetaImpl.connect(schema.root(), null);
-    CalciteSchema.TableEntry tableEntry = schema.getTableBySql(viewSql);
+    CalciteSchema.TableEntry tableEntry = schema.getTable(suggestedTableName, true);
+    if (tableEntry == null) {
+      tableEntry = schema.getTableBySql(viewSql);
+    }
     RelDataType rowType = null;
     if (tableEntry == null) {
       Table table = tableFactory.createTable(schema, viewSql, viewSchemaPath);
{code}

I also looked to see if there's any place for customization to add "viewSql --> table" mapping, but didn't seem to find one.

> Pre-populated materializations
> ------------------------------
>
>                 Key: CALCITE-761
>                 URL: https://issues.apache.org/jira/browse/CALCITE-761
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Assignee: Julian Hyde
>
> The design for materializations (materialized views) allows for them to be populated on demand (e.g. as an ArrayTable) the first time that the materialization is needed or to already exist, having been populated by the user.
> According to [~maryannxue] the latter case does not work. Calcite tries to create a new table with the same name as the current table, then makes the name unique by adding a digit, then goes ahead and populates it.
> We need to (a) allow such materializations to be defined in the JSON model, (b) document how to define them, (c) make them work, (d) add tests.
> Cc [~jamestaylor], as this is related to optimization for Phoenix secondary indexes.



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