在Neo4j中添加新节点时的查询性能 [英] Query performance when adding a new node in Neo4j
问题描述
我想知道为什么我的Cypher查询要花费大量时间.
I am wondering why my Cypher query is taking an exorbitant amount of time.
基本上，我有一棵小家族树(两个家族)，并且我正在尝试为每个家族添加一个新的节点，该节点带有少量的元数据，以便在家族之间更容易保持彼此隔离被查询. (感谢@Tim Kuehn对此
Basically, I have a small family tree (two families), and I'm trying to add to each one a new node that carries some small bit of metadata so that the families are easier to keep isolated from each other when they are queried. (Thanks to @Tim Kuehn for this advice).
运行查询以填充我的两个家庭之后，我就拥有了这个，可以快速构建而不会出现问题:
Once I run the query to populate my two families, I have this, which is built quickly with no problems:
接下来，我要创建上述新节点.快速创建了第一个节点，并将其应用于较小的系列(我称它们为B系列):
Next, I want to create the aforementioned new nodes. The first node is created quickly, applied to the smaller family (I call them family B):
// 'add a :Family node for each relational group, like so:'
CREATE (famB:Family)
WITH famB
MATCH (a:Person {name:"Gramps Johnson"})-[:RELATED_TO*]->(b:Person)
MERGE (famB:Family)<-[:FAMILY]-(a)
MERGE (famB:Family)<-[:FAMILY]-(b)
...这给了我.到目前为止，一切都很好！
...which gives me this. So far so good!
但是，由于某些原因，永远不会创建稍大的家庭节点.代码是一样的，但是查询只是运行而已...
Moving forward, however, the slightly larger family's node is never created for some reason. The code is the same, but the query just runs and runs...
// 'add a :Family node for each relational group, like so:'
CREATE (famA:Family)
WITH famA
MATCH (a:Person {name:"Gramps Doe"})-[:RELATED_TO*]->(b:Person)
MERGE (famA:Family)<-[:FAMILY]-(a)
MERGE (famA:Family)<-[:FAMILY]-(b)
为什么会这样?
我的第一个想法是在name属性上放置一个索引:
My first idea was to put an index on the name property:
// put index' on the name properties of the nodes:
// CREATE INDEX ON :Person(name)
但是什么也没做.
所以我尝试看一下EXPLAIN，但它并没有真正告诉我任何事情. (它在执行时也永远在终端上运行.)
So I tried to look at the EXPLAIN but it didn't really tell me anything. (It also runs forever on the terminal itself when executed.)
感谢您的帮助.
这是我创建图形的代码:
Here's my code to create the graph:
// FAMILY A2: create grandparents, their son.
CREATE (grampsdoe:Person {name: 'Gramps Doe', id:'1', Gender:'Male', Diagnosis: 'Alzheimers', `Is Alive?`: 'No', Handedness: 'Left', `Risk Score`: 'PURPLE'})
CREATE (gramsdoe:Person {name: 'Grams Doe', id:'2', Gender:'Female', Diagnosis: 'Alzheimers', `Is Alive?`: 'No', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE (daddoe:Person {name: 'Dad Doe', id:'3', Gender:'Male', Diagnosis: 'MCI', `Is Alive?`: 'No', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE
(grampsdoe)-[:RELATED_TO {relationship: 'Husband'}]->(gramsdoe),
(gramsdoe)-[:RELATED_TO {relationship: 'Wife'}]->(grampsdoe),
(grampsdoe)-[:RELATED_TO {relationship: 'Father'}]->(daddoe),
(gramsdoe)-[:RELATED_TO {relationship: 'Mother'}]->(daddoe),
(daddoe)-[:RELATED_TO {relationship: 'Son'}]->(grampsdoe),
(daddoe)-[:RELATED_TO {relationship: 'Son'}]->(gramsdoe)
// FAMILY A2: create grandparents, their daughter
CREATE (grampssmith:Person {name: 'Gramps Smith', id:'4', Gender:'Male', Diagnosis: 'Normal', `Is Alive?`: 'No', Handedness: 'Left', `Risk Score`: 'PURPLE'})
CREATE (gramssmith:Person {name: 'Grams Smith', id:'5', Gender:'Female', Diagnosis: 'Alzheimers', `Is Alive?`: 'No', Handedness: 'Ambidextrous', `Risk Score`: 'PURPLE'})
CREATE (momsmith:Person {name: 'Mom Doe', id:'6', Gender:'Female', Diagnosis: 'Alzheimers', `Is Alive?`: 'No', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE
(grampssmith)-[:RELATED_TO {relationship: 'Husband'}]->(gramssmith),
(gramssmith)-[:RELATED_TO {relationship: 'Wife'}]->(grampssmith),
(grampssmith)-[:RELATED_TO {relationship: 'Father'}]->(momsmith),
(gramssmith)-[:RELATED_TO {relationship: 'Mother'}]->(momsmith),
(momsmith)-[:RELATED_TO {relationship: 'Daughter'}]->(grampssmith),
(momsmith)-[:RELATED_TO {relationship: 'Daughter'}]->(gramssmith)
// FAMILY A3: 'Dad Doe' and 'Mom Smith' get married and have 2 kids who are twins
CREATE (lilbro:Person {name: 'Lil Bro', id:'7', Gender:'Male', Diagnosis: 'Normal', `Is Alive?`: 'Yes', Handedness: 'Right', `Risk Score`: 'PURPLE'})
CREATE (bigsis:Person {name: 'Big Sis', id:'8', Gender:'Female', Diagnosis: 'Normal', `Is Alive?`: 'Yes', Handedness: 'Right', `Risk Score`: 'PURPLE'})
CREATE (daddoe)-[:RELATED_TO {relationship: 'Husband'}]->(momsmith)
CREATE (momsmith)-[:RELATED_TO {relationship: 'Wife'}]->(daddoe)
CREATE (lilbro)-[:RELATED_TO {relationship: 'Brother'}]->(bigsis)
CREATE
(lilbro)-[:RELATED_TO {relationship: 'Grandson'}]->(grampsdoe),
(grampsdoe)-[:RELATED_TO {relationship: 'Grandfather'}]->(lilbro),
(lilbro)-[:RELATED_TO {relationship: 'Grandson'}]->(grampssmith),
(grampssmith)-[:RELATED_TO {relationship: 'Grandfather'}]->(lilbro),
(lilbro)-[:RELATED_TO {relationship: 'Grandson'}]->(grampssmith),
(grampssmith)-[:RELATED_TO {relationship: 'Grandmother'}]->(lilbro),
(lilbro)-[:RELATED_TO {relationship: 'Grandson'}]->(gramssmith),
(gramssmith)-[:RELATED_TO {relationship: 'Grandmother'}]->(lilbro),
(lilbro)-[:RELATED_TO {relationship: 'Son'}]->(daddoe),
(daddoe)-[:RELATED_TO {relationship: 'Father'}]->(lilbro),
(lilbro)-[:RELATED_TO {relationship: 'Son'}]->(momsmith),
(momsmith)-[:RELATED_TO {relationship: 'Mother'}]->(lilbro),
(bigsis)-[:RELATED_TO {relationship: 'Sister'}]->(lilbro),
(bigsis)-[:RELATED_TO {relationship: 'Granddaughter'}]->(grampsdoe),
(grampsdoe)-[:RELATED_TO {relationship: 'Grandfather'}]->(bigsis),
(bigsis)-[:RELATED_TO {relationship: 'Granddaughter'}]->(grampssmith),
(grampssmith)-[:RELATED_TO {relationship: 'Grandfather'}]->(bigsis),
(bigsis)-[:RELATED_TO {relationship: 'Granddaughter'}]->(gramsdoe),
(gramsdoe)-[:RELATED_TO {relationship: 'Grandmother'}]->(bigsis),
(bigsis)-[:RELATED_TO {relationship: 'Granddaughter'}]->(gramssmith),
(gramssmith)-[:RELATED_TO {relationship: 'Grandfather'}]->(bigsis),
(bigsis)-[:RELATED_TO {relationship: 'Daughter'}]->(daddoe),
(daddoe)-[:RELATED_TO {relationship: 'Father'}]->(bigsis),
(bigsis)-[:RELATED_TO {relationship: 'Daughter'}]->(momsmith),
(momsmith)-[:RELATED_TO {relationship: 'Mother'}]->(bigsis)
// FAMILY B1: create grandparents, their son.
CREATE (grampsjohnson:Person {name: 'Gramps Johnson', id:'9', Gender:'Male', Diagnosis: 'Normal', `Is Alive?`: 'No', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE (gramsjohnson:Person {name: 'Grams Johnson', id:'10', Gender:'Female', Diagnosis: 'Normal', `Is Alive?`: 'No', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE (johnjohnson:Person {name: 'John Johnson', id:'11', Gender:'Male', Diagnosis: 'MCI', `Is Alive?`: 'Yes', Handedness: 'Right', `Risk Score`: 'GIRAFFE'})
CREATE
(grampsjohnson)-[:RELATED_TO {relationship: 'Husband'}]->(gramsjohnson),
(gramsjohnson)-[:RELATED_TO {relationship: 'Wife'}]->(grampsjohnson),
(grampsjohnson)-[:RELATED_TO {relationship: 'Father'}]->(johnjohnson),
(gramsjohnson)-[:RELATED_TO {relationship: 'Mother'}]->(johnjohnson),
(johnjohnson)-[:RELATED_TO {relationship: 'Son'}]->(grampsjohnson),
(johnjohnson)-[:RELATED_TO {relationship: 'Son'}]->(gramsjohnson)
推荐答案
为什么会这样?
Why would this happen?
发生这种情况的原因是第二个家庭不再是一个循环，而是每个人两次联系到每个人".这意味着制作家庭节点"代码的这一部分:
The reason that was happening is the second family wasn't a loop any more, it was a "everyone connected twice to everyone". That meant this part of the "make a family node" code:
MATCH (a:Person {name:"Gramps Doe"})-[:RELATED_TO*]->(b:Person)
跟踪了大量图形，结果系统停滞了.
was tracing a huge number of graphs, and the system was stalling as a result.
由于目标组中有8个节点，因此我将路径限制为1到8个跃点( [:RELATED_TO * 1..8] )-
Since there's 8 nodes in the target group, I restricted the pathing to a range of 1 to 8 hops ([:RELATED_TO*1..8]) -
CREATE (famA:Family)
WITH famA
MATCH (a:Person {name:"Gramps Doe"})-[:RELATED_TO*1..8]->(b:Person)
MERGE (famA:Family)<-[:FAMILY]-(a)
MERGE (famA:Family)<-[:FAMILY]-(b)
然后就完成了.
要让整个家庭出现疾病一定次数:
To get the entire family where a disease has shown up a certain number of times:
// count the family members with a disease
MATCH (f:Family)<-[:FAMILY]-(person:Person)
WHERE person.Diagnosis = "Alzheimers"
WITH f, count(person) AS Count
WHERE Count > 2
// Then report the family members as a single collection
MATCH (a:Person)-[r1:FAMILY]-(f)
RETURN collect(DISTINCT a)
这篇关于在Neo4j中添加新节点时的查询性能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
