在Neo4j中添加新節點時的查詢性能

Question

我想知道為什么我的Cypher查詢要花費大量時間。

基本上，我有一棵小家族樹（兩個家族），並且我試圖為每個家族添加一個新的節點，該節點攜帶少量的元數據，以便在查詢這些家族時更易於彼此隔離。 （感謝@Tim Kuehn的建議 ）。

一旦運行查詢以填充我的兩個家庭，我就會擁有一個快速建立的沒有問題的對象：

接下來，我要創建上述新節點。 快速創建了第一個節點，並將其應用於較小的系列（我稱它們為B系列）：

// '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) 

...這給了我。 到現在為止還挺好！

然而，由於某些原因，永遠不會創建稍大的家庭節點。 代碼是一樣的，但是查詢只是運行而已...

// '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)

為什么會這樣？

我的第一個想法是在name屬性上放置一個索引：

// put index' on the name properties of the nodes:
// CREATE INDEX ON :Person(name)  

但這什么也沒做。

所以我試圖看一下EXPLAIN，但它並沒有真正告訴我任何事情。 （它在執行時也永遠在終端本身上運行。）

謝謝你的幫助。

這是我創建圖形的代碼：

// 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)

Answer 1

為什么會這樣？

發生這種情況的原因是第二個家庭不再是一個循環，而是“每個人兩次聯系到每個人”。 這意味着“建立家庭節點”代碼的這一部分：

MATCH (a:Person {name:"Gramps Doe"})-[:RELATED_TO*]->(b:Person)  

正在跟蹤大量圖形，結果系統停滯了。

由於目標組中有8個節點，因此我將路徑限制為1到8個躍點（ [：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)

這樣就完成了。

為了使整個家庭出現某種疾病：

// 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)