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https://issues.apache.org/jira/browse/TINKERPOP-1473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15628684#comment-15628684
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ASF GitHub Bot commented on TINKERPOP-1473:
-------------------------------------------
GitHub user okram opened a pull request:
https://github.com/apache/tinkerpop/pull/477
TINKERPOP-1473: Given PathRetractionStrategy, PathProcessorStrategy can be
extended to support partial where() inlining.
https://issues.apache.org/jira/browse/TINKERPOP-1473
Extended `PathProcessStrategy` to support the following translations which
expose more traversals to OLAP processing (works around local star graph
violations).
```
where(as(a).out().as(b)) => as(xyz).select(a).where(out().as(b)).select(xyz)
where(as(a).out()) => as(xyz).select(a).filter(out()).select(xyz)
```
Next, given that `PathProcessStrategy` is prior to `InlineFilterStrategy`
you get this effect:
where(as(a).has(z)) => as(xyz).select(a).has(z).select(xyz)
```
You can see why `PathRetractionStrategy` is important. Without it `xyz`
(which are UUIDs in practice) would remain in the traverser's path data.
VOTE +1.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/apache/tinkerpop TINKERPOP-1473
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/tinkerpop/pull/477.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #477
----
commit a69efffef138b036581fdb8c5bcd22c8075aa846
Author: Marko A. Rodriguez <[email protected]>
Date: 2016-11-02T10:50:57Z
Added where(a.out.b) => select(a).where(out.b) AND where(a.out) =>
select(a).filter(out) to PathProcessorStrategy (an OLAP strategy). This opens
up more traversals that would otherwise break the star-graph local child
constraint in OLAP.
----
> Given PathRetractionStrategy, PathProcessorStrategy can be extended to
> support partial where() inlining.
> --------------------------------------------------------------------------------------------------------
>
> Key: TINKERPOP-1473
> URL: https://issues.apache.org/jira/browse/TINKERPOP-1473
> Project: TinkerPop
> Issue Type: Improvement
> Components: process
> Affects Versions: 3.2.2
> Reporter: Marko A. Rodriguez
> Assignee: Marko A. Rodriguez
>
> {{PathProcessorStrategy}} has a big chunk of code commented out in it that
> says: "todo: need to be able to drop path labels for this to work."
> Given {{PathRetractionStrategy}}, we can now support:
> {code}
> where(as('a').out().as('b')) => select('a').where(out().as('b'))
> {code}
> This is useful for OLAP when you can only process the local star graph and
> thus, if {{where()}} selects arbitrarily from a path, this rewrite will
> ensure that the {{where()}} starts at a local star graph and not a "reference
> element" in the path object.
> Note that {{PathProcessorStrategy}} already has test cases for this too
> (commented out). Just uncomment stuff and go!
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