[teiid-issues] [JBoss JIRA] Commented: (TEIID-1529) LIMIT not pushed down for queries with subselects and ORDER BY

LIMIT not pushed down for queries with subselects and ORDER BY -------------------------------------------------------------- Key: TEIID-1529 URL: https://issues.jboss.org/browse/TEIID-1529 Project: Teiid Issue Type: Bug Components: Query Engine Affects Versions: 7.3 Reporter: Mark Addleman Assignee: Steven Hawkins Fix For: 7.4 It doesn't look like the engine pushes down LIMIT in the following query: SELECT B."SYSID", B."USERID", (SELECT COUNT(*) FROM (SELECT * FROM notes.RETRIEVE_NOTES WHERE OBJECT_PKEY = XMLSERIALIZE(XMLELEMENT("SECURITY.BASEUSER", XMLATTRIBUTES(B."SYSID",B."USERID")) as String)) as foo) as C_notesForObject, 'SECURITY.BASEUSER' as "__objecttype__" FROM "SECURITY.BASEUSER" as B ORDER BY B."USERID" ASC LIMIT 10 However, the engine does push down the LIMIT in the same query without the ORDER BY: SELECT B."SYSID", B."USERID", (SELECT COUNT(*) FROM (SELECT * FROM notes.RETRIEVE_NOTES WHERE OBJECT_PKEY = XMLSERIALIZE(XMLELEMENT("SECURITY.BASEUSER", XMLATTRIBUTES(B."SYSID",B."USERID")) as String)) as foo) as C_notesForObject, 'SECURITY.BASEUSER' as "__objecttype__" FROM "SECURITY.BASEUSER" as B LIMIT 10 Another piece of relevant information is notes.RETRIEVE_NOTE is a stored procedure backed by java code in a translator. Since SECURITY.BASEER contains ~20,000 rows and each row requires a select against the RETRIEVE_NOTE stored procedure, the difference in processing time is huge: about two minutes with the ORDER BY versus a few hundred milliseconds without the ORDER BY.