[
https://issues.apache.org/jira/browse/OAK-1617?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Davide Giannella updated OAK-1617:
----------------------------------
Attachment: OAK-1617-3.patch
in [^OAK-1617-3.patch] the last patch which will address OAK-2660 as
well.
To summarise.
The feature is currently disabled. To enable it provide the flag
{{-Doak.query.sql2optimisation}}.
The {{Query}} now exposes a {{Query#getCostOverhead()}} which can be
used to instruct the query engine around behaviours on choosing one
version rather the other: original SQL2 vs Optimised/Union.
If no optimisations are available it will pick the original statement,
otherwise it will analyse (prepare and cost) both the queries:
original and union and pick the cheapest.
The changes currently support only one optimisation query off the
original statement but with a quick change it will be possible to
extend the concept to be able to provide multiple optimisations which
can then be analysed to see what is the cheapest.
[~tmueller] could you please review?
> Automatically convert "or" queries to "union" for SQL-2
> -------------------------------------------------------
>
> Key: OAK-1617
> URL: https://issues.apache.org/jira/browse/OAK-1617
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: query
> Reporter: Thomas Mueller
> Assignee: Davide Giannella
> Priority: Minor
> Fix For: 1.3.9
>
> Attachments: OAK-1617-1.patch, OAK-1617-2.patch, OAK-1617-3.patch
>
>
> XPath queries that contain "or" conditions are automatically converted to
> "union" SQL-2 queries. However, SQL-2 queries that contain "or" conditions
> are not (yet).
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
