Michael, I apologize, I will send you a copy of the query + profile too.
In my actual query, I am using a parameter of the cypher query:
WHERE other.birth_year > (me.birth_year - {age_difference_range})
AND other.birth_year < (me.birth_year + {age_difference_range})
here is the relevant profile portion:
Filter
pred="(((Property(other,birth_year(66)) >
Subtract(Property(me,birth_year(66)),Literal(10)) AND
Property(other,birth_year(66)) <
Add(Property(me,birth_year(66)),Literal(10))) AND
Property(sv,cached_available(71)) == Literal(1)) AND
hasLabel(sv:StyleVariant(13)))",
_rows=47,
_db_hits=4860
On Tuesday, January 21, 2014 11:11:57 AM UTC-6, Michael Hunger wrote:
>
> The problem is cross-path expressions, which are not yet handled in that
> manner
>
> for simple expressions that only contain a single piece of the path (node,
> rel) and things that have been evaluated before (parameters, literals,
> previous computations) WILL be used to shortcut the path evaluation.
>
> but if you do: n1--n2--n3
>
> and then WHERE n2.foo > n1.bar it will be only applied AFTER the path
>
> if you do: WHERE n1.foo > 10 it will be applied DURING the path traversal
>
> HTH
>
> Michael
>
> Am 21.01.2014 um 18:08 schrieb Javad Karabi <[email protected]<javascript:>
> >:
>
> You will notice:
> "WHERE (Property(NodeIdentifier(),cached_available(71)) == Literal(1)" in
> the TraversalMatcher() portion, the very first function of the profile..
>
> I believe that this is what is meant when the documentation says that the
> WHERE clause is not done after, (therefore during) the matching process.
>
> However, you will also notice that immediately following that function, is
> Filter(), which is then filtering based on the ">" and "<" predicates of
> the query.
>
> obviously, the best case scenario would be if the ">" and "<" tests
> occurred inside TraversalMatcher(), i think
>
> On Tuesday, January 21, 2014 11:06:06 AM UTC-6, Javad Karabi wrote:
>>
>> Mark, I have emailed you the query and profile for both cases.
>>
>> On Tuesday, January 21, 2014 10:55:03 AM UTC-6, Javad Karabi wrote:
>>>
>>> Mark, I would be happy to. Give me a moment and I will post them.
>>>
>>> Michael,
>>>
>>> - Kernel version
>>>
>>> neo4j-browser, version: 2.0.0
>>> -
>>>
>>>
>>> On Tuesday, January 21, 2014 10:49:37 AM UTC-6, Michael Hunger wrote:
>>>>
>>>> Java, what version are you using?
>>>>
>>>> 2.0 final?
>>>>
>>>> Michael
>>>>
>>>> Am 21.01.2014 um 17:29 schrieb Javad Karabi <[email protected]>:
>>>>
>>>> from what I can tell, if there where clause is ">" or "<" (as it is in
>>>> the actual query which i am using, not in this example query...) then the
>>>> WHERE predicate _is in fact_ a filter, applied _after_ the match. It looks
>>>> to me that "TraversalMatcher()" does not apply predicates which involve >
>>>> or <, but instead delegates this to "Filter()" after the fact, which does
>>>> not correlate with what is stated on the documentation.
>>>>
>>>> On Tuesday, January 21, 2014 10:25:41 AM UTC-6, Javad Karabi wrote:
>>>>>
>>>>> (c:Customer)-[:ordered]->(p:Product)-[:category]->(:Category)
>>>>>
>>>>> Now, say that there are 2:
>>>>> c-[:ordered]->(:Product { name: "pants", quantity: 10})
>>>>> c-[:ordered]->(:Product { name: "shirt", quantity: 5})
>>>>>
>>>>> Now, say that if I only want to cross the category relationship if the
>>>>> p.quantity > 6
>>>>>
>>>>> In the most basic way, I would do:
>>>>>
>>>>> (c:Customer)-[:ordered]->(p:Product)-[:category]->(cat:Category)
>>>>> WHERE p.quantity > 6
>>>>>
>>>>> However, I figured that maybe neo4j would (non-optimally) traverse the
>>>>> entire path _then_ filter where on top of the path.
>>>>>
>>>>> So what I did was:
>>>>>
>>>>> MATCH (c:Customer)-[:ordered]->(p:Product)
>>>>> WHERE p.quantity > 6
>>>>> WITH p
>>>>> MATCH p-[:category]->(cat:Category)
>>>>>
>>>>> This, I figured, would then allow neo4j to cross out to all the
>>>>> product nodes, as I would need them anyway in order to filter out the
>>>>> ones
>>>>> which have a quantity of less than 6.
>>>>>
>>>>>
>>>>> Now... finally to my question.
>>>>> The following URL:
>>>>> http://docs.neo4j.org/chunked/stable/query-match.html
>>>>> states that:
>>>>> WHERE defines the MATCH patterns in more detail. The predicates are
>>>>> part of the pattern description, not a filter applied after the matching
>>>>> is
>>>>> done.
>>>>>
>>>>> So, my question is, if the predicates (specifically p.quantity > 6)
>>>>> are part of the pattern description, and _not_ applied _after_ matching
>>>>> (therefore applied before or during), then cutting the query with the
>>>>> WITHs
>>>>> would be a moot point
>>>>>
>>>>> So, I would think that
>>>>>
>>>>> (c:Customer)-[:ordered]->(p:Product)-[:category]->(cat:Category)
>>>>> WHERE p.quantity > 6
>>>>> would be sufficient, , as neo4j _would not_ actually traverse to cat,
>>>>> since it would apply the filter during the match process.
>>>>>
>>>>> However, in practice, I notice that using WITH is actually faster. Is
>>>>> there any possible reason for this?
>>>>> It may be necessary for me to show my query exactly, I also have the
>>>>> profile data for the query, which I am currently analyzing
>>>>>
>>>>
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>>>>
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