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https://issues.apache.org/jira/browse/DRILL-4577?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15227149#comment-15227149
]
ASF GitHub Bot commented on DRILL-4577:
---------------------------------------
Github user jinfengni commented on a diff in the pull request:
https://github.com/apache/drill/pull/461#discussion_r58616431
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/AbstractSchema.java ---
@@ -194,4 +195,26 @@ public void dropTable(String tableName) {
.message("Dropping tables is not supported in schema [%s]",
getSchemaPath())
.build(logger);
}
-}
+
+ /**
+ * Visit the tables in this schema and write to recordGenerator
+ * @param recordGenerator recordGenerator for the output
+ * @param schemaPath the path to the given schema
+ */
--- End diff --
Why do you add this API to AbstractSchema? We should not put the logic of
RecordGenerator in Schema.
A cleaner way is to add getTablesByNames() in AbstractSchema, and leave the
logic of iterating and record generating to RecordGenerator. If the underlying
storage supports bulk load ( like Hive does), then use the bulk load.
Otherwise, just call getTable() individually for getTablesByNames().
> Improve performance for query on INFORMATION_SCHEMA when HIVE is plugged in
> ---------------------------------------------------------------------------
>
> Key: DRILL-4577
> URL: https://issues.apache.org/jira/browse/DRILL-4577
> Project: Apache Drill
> Issue Type: Improvement
> Components: Storage - Hive
> Reporter: Sean Hsuan-Yi Chu
> Assignee: Sean Hsuan-Yi Chu
> Fix For: 1.7.0
>
>
> A query such as
> {code}
> select * from INFORMATION_SCHEMA.`TABLES`
> {code}
> is converted as calls to fetch all tables from storage plugins.
> When users have Hive, the calls to hive metadata storage would be:
> 1) get_table
> 2) get_partitions
> However, the information regarding partitions is not used in this type of
> queries. Beside, a more efficient way is to fetch tables is to use
> get_multi_table call.
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