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https://issues.apache.org/jira/browse/DRILL-4826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15573420#comment-15573420
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ASF GitHub Bot commented on DRILL-4826:
---------------------------------------
Github user ppadma commented on a diff in the pull request:
https://github.com/apache/drill/pull/592#discussion_r83324461
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/ischema/InfoSchemaRecordGenerator.java
---
@@ -290,28 +290,30 @@ public Tables(OptionManager optionManager) {
return new PojoRecordReader<>(Records.Table.class,
records.iterator());
}
- @Override
- public void visitTables(String schemaPath, SchemaPlus schema) {
+ @Override public void visitTables(String schemaPath, SchemaPlus
schema) {
--- End diff --
why this change ?
> Query against INFORMATION_SCHEMA.TABLES degrades as the number of views
> increases
> ---------------------------------------------------------------------------------
>
> Key: DRILL-4826
> URL: https://issues.apache.org/jira/browse/DRILL-4826
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Parth Chandra
> Assignee: Padma Penumarthy
>
> Queries against INFORMATION_SCHEMA.TABLES and INFORMATION_SCHEMA.VIEWS slow
> down as the number of views increases.
> BI tools like Tableau issue a query like the following at connection time:
> {code}
> select TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE from
> INFORMATION_SCHEMA.`TABLES` WHERE TABLE_CATALOG LIKE 'DRILL' ESCAPE '\' AND
> TABLE_SCHEMA <> 'sys' AND TABLE_SCHEMA <> 'INFORMATION_SCHEMA'ORDER BY
> TABLE_TYPE, TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME
> {code}
> The time to query the information schema tables degrades as the number of
> views increases. On a test system:
> || Views || Time(secs) ||
> |500 | 6 |
> |1000 | 19 |
> |1500 | 33 |
> This can result in a single connection taking more than a minute to establish.
> The problem occurs because we read the view file for every view and this
> appears to take most of the time.
> Querying information_schema.tables does not, in fact, need to open the view
> file at all, it merely needs to get a listing of the view files. Eliminating
> the view file read will speed up the query tremendously.
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