[
https://issues.apache.org/jira/browse/DERBY-4422?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12770560#action_12770560
]
Tony Brusseau commented on DERBY-4422:
--------------------------------------
Yeah the query plans that I added were for the real query that I'm trying to
optimize.
SELECT DISTINCT C.EXTERNAL_ID, C.OWL_NL_ID, CYCL, C.PREFERRED_NL,
C.PREFERRED_NL_SORTABLE, C.COMMENT, C.CONCEPT_TYPE, CS.NL, CS.STRING_TYPE,
C.INTERNAL_ID FROM OC_CONCEPTS C, OC_CONCEPT_STRINGS CS
WHERE
(C.INTERNAL_ID IN (SELECT DISTINCT OCS.CONCEPT_ID FROM OC_CONCEPT_STRINGS
OCS WHERE OCS.NL_LC like 'dash%'))
AND
(C.INTERNAL_ID = CS.CONCEPT_ID)
ORDER BY C.PREFERRED_NL_SORTABLE, C.INTERNAL_ID, CS.STRING_TYPE
I'll add query plans for the queries I mentioned in the original report (which
are simplifications of this query) in a bit.
> Extremely slow subqueries when subquerying on strings
> -----------------------------------------------------
>
> Key: DERBY-4422
> URL: https://issues.apache.org/jira/browse/DERBY-4422
> Project: Derby
> Issue Type: Bug
> Affects Versions: 10.5.3.0
> Environment: Suse Unix 10.3.
> Reporter: Tony Brusseau
> Attachments: fixed-time-derby.log, tmp2.sql, unlimited-time-derby.log
>
>
> SELECT DISTINCT C.INTERNAL_ID
> FROM OC_CONCEPTS C
> WHERE
> (C.INTERNAL_ID IN (SELECT DISTINCT OCS.CONCEPT_ID FROM OC_CONCEPT_STRINGS
> OCS WHERE OCS.CONCEPT_ID=1))
> Both queries above are trivial and they are both acting on fully indexed
> primary key columns. This query runs just fine.
> However, when I make the small modification of searching on an indexed text
> column in the sub query, it takes over 6 seconds to run, even though both
> queries independently take < 1ms run.
> SELECT DISTINCT C.INTERNAL_ID
> FROM OC_CONCEPTS C
> WHERE
> (C.INTERNAL_ID IN (SELECT DISTINCT OCS.CONCEPT_ID FROM OC_CONCEPT_STRINGS
> OCS WHERE OCS.NL_LC = 'dash'))
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
