[teiid-issues] [JBoss JIRA] (TEIID-4452) Pushdown SQL/XML
Steven Hawkins (JIRA)
issues at jboss.org
Wed Oct 4 13:44:00 EDT 2017
[ https://issues.jboss.org/browse/TEIID-4452?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Steven Hawkins updated TEIID-4452:
----------------------------------
Fix Version/s: 10.x
(was: 10.0)
> Pushdown SQL/XML
> ----------------
>
> Key: TEIID-4452
> URL: https://issues.jboss.org/browse/TEIID-4452
> Project: Teiid
> Issue Type: Enhancement
> Components: JDBC Connector
> Affects Versions: 9.x
> Reporter: Tom Arnold
> Fix For: 10.x
>
>
> It would be helpful to pushdown SQL/XML functions for JDBC databases that support them.
> Databases:
> - Oracle
> - Postgres
> Functions:
> - XMLELEMENT
> - XMLATTRIBUTES
> - XMLAGG
> - XMLCONCAT
> We have an application that uses these functions and we support Oracle, Postgres, and Teiid (to integrate external data sources). Here's an example query generated by this application:
> {code:xml}
> select
> "ITEMS"."ITEM_ID" "ITEM_ID",
> (
> select xmlelement (
> name "attributes",
> xmlagg(
> xmlelement(
> name "attribute",
> xmlattributes(
> "ITEM_ATTRIBUTES"."ATTR_NAME" as "name",
> "ITEM_ATTRIBUTES"."ATTR_VALUE" as "value"
> )
> )
> )
> )
> from "ITEM_ATTRIBUTES" "ITEM_ATTRIBUTES"
> where (
> "ITEMS"."ITEM_ID" = "ITEM_ATTRIBUTES"."ITEM_ID"
> )
> ) "ITEM_ATTRIBUTES"
> {code}
> {code}
> ITEM_ID ITEM_ATTRIBUTES
> 3 <attributes><attribute name="foo" value="bar"></attribute><attribute name="baz" value="blah"></attribute></attributes>
> 4 <attributes><attribute name="foo" value="123"></attribute><attribute name="baz" value="456"></attribute></attributes>
> {code}
> When we are using Teiid queries like this do not work well because they cannot be pushed down, so we get N-many queries (one per row) and the query ends up taking much longer than if performed directly against Oracle/Postgres.
> Since SQL/XML is standard and supported by both Oracle/Postgres it would be good if queries like this could be pushed in their entirety so that there would be no performance difference between going through Teiid and native.
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