Right, cross path comparisons are not yet used to shortcut path-finding
so if you rewrite your query to this, it will actually filter down the paths
eagerly
MATCH (me:Member {id: 11700})
WITH me, me.birth_year as birth_year
MATCH
(me)-[ra:preferred_store]->(s)<-[rb:preferred_store]-(other)-[rc:ordered]->()<-[rd:product]-(sv:StyleVariant)
WHERE abs(other.birth_year - birth_year ) < {age_difference_range} AND
sv.cached_available = 1
....
Am 21.01.2014 um 18:19 schrieb Javad Karabi <[email protected]>:
> 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]>:
>
>> 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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