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https://issues.apache.org/jira/browse/JENA-1257?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15626827#comment-15626827
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Andy Seaborne commented on JENA-1257:
-------------------------------------
This is not the same situation as the [referenced
email|http://mail-archives.apache.org/mod_mbox/jena-users/201611.mbox/%3c58185a49.7060...@helsinki.fi%3e].
In the email, the issue is that VALUES at the end of the query makes it a
different query to when the VALUEs is at the front.
> Bad performance with VALUES blocks
> ----------------------------------
>
> Key: JENA-1257
> URL: https://issues.apache.org/jira/browse/JENA-1257
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 3.1.1
> Environment: Ubuntu 12.04 LTS amd64
> java version "1.8.0_91" (Oracle)
> Reporter: Osma Suominen
> Labels: performance
> Attachments: explain.zip
>
>
> I'm having performance issues with a query involving VALUES blocks. It seems
> to me that the values are bound to variables too late, which causes long
> execution times.
> Also discussed on users list:
> http://mail-archives.apache.org/mod_mbox/jena-users/201611.mbox/%3c58185a49.7060...@helsinki.fi%3e
> Steps to repeat:
> 1. Create a TDB with YSO:
> {noformat}
> wget http://api.finto.fi/download/yso/yso-skos.ttl
> tdbloader --loc YSO yso-skos.ttl
> {noformat}
> 2. Run the below query against the TDB:
> {noformat}
> tdbquery --loc YSO --query ysoslowunion.rq
> {noformat}
> Contents of ysoslowunion.rq:
> {noformat}
> PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
> SELECT *
> WHERE {
> VALUES ?uri { <http://www.yso.fi/onto/yso/p864> }
> { ?s ?p ?uri }
> UNION
> { ?uri ?p ?o
> OPTIONAL {
> ?x skos:member ?o .
> FILTER NOT EXISTS {
> ?x skos:member ?other .
> FILTER NOT EXISTS {
> ?other skos:broader ?uri
> }
> }
> }
> }
> }
> {noformat}
> With Jena 3.1.0 this takes <1 second.
> With current 3.1.1 snapshot it takes 12 seconds.
> Possibly related to changes made in JENA-1167.
> I will attach --explain output for both versions as a zip. The 3.1.1 output
> is 473 MB uncompressed.
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