Question

-file-name.csv在上一个问题上 How to make the Cypher request to handle those both cases without duplicating Nodes

我做的第一步

CREATE CONSTRAINT ON (r:Region) ASSERT r.region IS UNIQUE;
CREATE CONSTRAINT ON (c:City) ASSERT c.cityName IS UNIQUE;
CREATE CONSTRAINT ON (s:Sector) ASSERT s.sectorName IS UNIQUE;

这里我把cypher查询。

LOAD CSV WITH HEADERS FROM "file:///the-file-name.csv" as line 
FIELDTERMINATOR ','  
with line as line
OPTIONAL MATCH (n:Region) 
WHERE  n.region contains "BLANKEMPTYVIDE" AND n.identifier= line.CODE_TER 
WITH n, line
CALL apoc.do.when(
   n IS NULL,
  'MERGE (r:Region{region: line.TERRITOIRE}) ON CREATE SET r.description=line.TERRITOIRE ON CREATE SET r.identifier=line.CODE_TER ON CREATE SET r.id = toString(id(r)) RETURN r',
  'RETURN n AS r',
  {n: n, line: line}) YIELD value
WITH value.r AS r, line 
SET r.identifier=line.CODE_TER
SET r.description=line.TERRITOIRE
SET r.region=line.TERRITOIRE
WITH r,line
OPTIONAL MATCH (ci:City) where ci.cityName contains "BLANKEMPTYVIDE" AND ci.regionIdentifier= line.CODE_TER
CALL apoc.do.when(
   ci IS NULL,
  'MERGE (c:City {cityName:line.BRICK}) ON CREATE SET c.identifier=line.CODE_BRICK ON CREATE SET c.region=line.TERRITOIRE ON CREATE SET c.regionIdentifier=line.CODE_TER ON CREATE SET c.zip=line.CODE_BRICK ON CREATE SET c.description=line.BRICK ON CREATE SET c.id = toString(id(c)) RETURN c',
  'RETURN ci AS c',
  {ci: ci, line: line}) YIELD value
WITH value.c AS c,line,r
SET c.identifier=line.CODE_BRICK 
SET c.region=line.TERRITOIRE
SET c.regionIdentifier=line.CODE_TER
SET c.zip=line.CODE_BRICK
SET c.description=line.BRICK
SET c.cityName=line.BRICK  
WITH c,r,line
MATCH (c {identifier:line.CODE_BRICK}),(r {identifier:line.CODE_TER})
MERGE (c)-[:IS_A_City_BELONGING_TO]->(r)
WITH c,r,line
OPTIONAL MATCH (sec:Sector) 
WHERE  sec.description contains "BLANKEMPTYVIDE" AND sec.regionIdentifier=line.CODE_TER 
CALL apoc.do.when(
   sec IS NULL,
  'MERGE (s:Sector {sectorName:line.SOUSBRICK}) ON CREATE SET s.identifier=line.CODE_SBRICK ON CREATE SET s.region=line.TERRITOIRE ON CREATE SET s.regionIdentifier=line.CODE_TER ON CREATE SET s.city=line.BRICK ON CREATE SET s.cityIdentifier=line.CODE_BRICK ON CREATE SET s.description=line.SOUSBRICK ON CREATE SET s.zip=line.SOUSBRICK ON CREATE SET s.id = toString(id(s)) RETURN s',
  'RETURN sec AS s',
  {sec: sec, line: line}) YIELD value
WITH value.s AS s,line,c,r
SET s.identifier=line.CODE_SBRICK 
SET s.region=line.TERRITOIRE 
SET s.regionIdentifier=line.CODE_TER 
SET s.city=line.BRICK 
SET s.cityIdentifier=line.CODE_BRICK 
SET s.description=line.SOUSBRICK 
SET s.zip=line.SOUSBRICK 
SET s.sectorName = line.SOUSBRICK   
WITH s,c,r,line
MATCH (s {identifier:line.CODE_SBRICK}),(r{identifier:line.CODE_TER}) 
MERGE (s)-[:IS_A_SECTOR_BELONGING_TO_THAT_REGION]->(r) 
WITH s,c,r,line
MATCH (s {identifier:line.CODE_SBRICK}),(c{identifier:line.CODE_BRICK})
MERGE (s)-[:IS_A_SECTOR_BELONGING_TO_THAT_CITY]->(c)

结果：

设置28271个属性，创建3400个关系，在34985毫秒后完成。

将csv加载到neo4j db需要35秒。请问在性能方面是否完美？

表示包含1665个csv行的csv文件每行包含6个字段：（Region）第三个和第四个（City）的两个第一个字段，（Sector）的第五个和第六个字段。

如何优化这个neo4j查询，以便在3秒内只需几秒钟？

下面我将调查结果图片放入。

在这里，我根据InverseFalcon的建议进行了更新

LOAD CSV WITH HEADERS FROM "file:///the-file-name.csv" as line 
FIELDTERMINATOR ','  
with line as line
OPTIONAL MATCH (n:Region) 
WHERE  n.region contains "BLANKEMPTYVIDE" AND n.identifier= line.CODE_TER 
WITH n, line
CALL apoc.do.when(
   n IS NULL,
  'MERGE (r:Region{region: line.TERRITOIRE}) ON CREATE SET r.description=line.TERRITOIRE ON CREATE SET r.identifier=line.CODE_TER ON CREATE SET r.id = toString(id(r)) RETURN r',
  'SET n.identifier=line.CODE_TER  SET n.description=line.TERRITOIRE  SET n.region=line.TERRITOIRE RETURN n AS r',
  {n: n, line: line}) YIELD value
WITH value.r AS r, line 

OPTIONAL MATCH (ci:City) where ci.cityName contains "BLANKEMPTYVIDE" AND ci.regionIdentifier= line.CODE_TER
CALL apoc.do.when(
   ci IS NULL,
  'MERGE (c:City {cityName:line.BRICK}) ON CREATE SET c.identifier=line.CODE_BRICK ON CREATE SET c.region=line.TERRITOIRE ON CREATE SET c.regionIdentifier=line.CODE_TER ON CREATE SET c.zip=line.CODE_BRICK ON CREATE SET c.description=line.BRICK ON CREATE SET c.id = toString(id(c)) RETURN c',
  'SET ci.identifier=line.CODE_BRICK SET ci.region=line.TERRITOIRE SET ci.regionIdentifier=line.CODE_TER SET ci.zip=line.CODE_BRICK SET ci.description=line.BRICK SET ci.cityName=line.BRICK  RETURN ci AS c',
  {ci: ci, line: line}) YIELD value
WITH value.c AS c,line,r
MERGE (c)-[:IS_A_City_BELONGING_TO]->(r)
WITH c,r,line
OPTIONAL MATCH (sec:Sector) 
WHERE  sec.description contains "BLANKEMPTYVIDE" AND sec.regionIdentifier=line.CODE_TER 
CALL apoc.do.when(
   sec IS NULL,
  'MERGE (s:Sector {sectorName:line.SOUSBRICK}) ON CREATE SET s.identifier=line.CODE_SBRICK ON CREATE SET s.region=line.TERRITOIRE ON CREATE SET s.regionIdentifier=line.CODE_TER ON CREATE SET s.city=line.BRICK ON CREATE SET s.cityIdentifier=line.CODE_BRICK ON CREATE SET s.description=line.SOUSBRICK ON CREATE SET s.zip=line.SOUSBRICK ON CREATE SET s.id = toString(id(s)) RETURN s',
  'SET sec.identifier=line.CODE_SBRICK SET sec.region=line.TERRITOIRE SET sec.regionIdentifier=line.CODE_TER SET sec.city=line.BRICK SET sec.cityIdentifier=line.CODE_BRICK SET sec.description=line.SOUSBRICK SET sec.zip=line.SOUSBRICK SET sec.sectorName = line.SOUSBRICK   RETURN sec AS s',
  {sec: sec, line: line}) YIELD value
WITH value.s AS s,line,c,r
MERGE (s)-[:IS_A_SECTOR_BELONGING_TO_THAT_REGION]->(r) 
WITH s,c,r,line
MERGE (s)-[:IS_A_SECTOR_BELONGING_TO_THAT_CITY]->(c)

为部门描述添加了索引 约束成为

CREATE CONSTRAINT ON (r:Region) ASSERT r.region IS UNIQUE;
CREATE CONSTRAINT ON (c:City) ASSERT c.cityName IS UNIQUE;
CREATE CONSTRAINT ON (s:Sector) ASSERT s.sectorName IS UNIQUE;
CREATE CONSTRAINT ON (s:Sector) ASSERT s.description IS UNIQUE;

从分析器计划

Cypher版本：CYPHER 3.4，规划器：COST，运行时间：解释。在14321毫秒内总共有175350次点击率****

直接没有Profiler 创建3403关系，在12702毫秒后完成。

从36秒到12秒的良好增强，但仍需要优化。

Answer 1

具有最大数据库命中的操作引用NodeByLabelScan，后跟过滤器，仅产生1663行或来自标签的起始130万个节点的结果。如果可能的话，这似乎是一个添加索引的机会。

您还没有在查询计划中扩展节点，因此我们无法看到与这些数据库命中相关联的查询部分的任何信息，但是如果我猜测它将来自此处：

OPTIONAL MATCH (sec:Sector) 
WHERE  sec.description contains "BLANKEMPTYVIDE" AND sec.regionIdentifier=line.CODE_TER

我没有看到任何证据表明您已经创建了约束或索引：扇区（描述）或：扇区（regionIdentifier），因此这可能是规划者被迫使用NodeByLabelScan的地方，正如您所看到的太贵了。您将需要其中一个索引或一个唯一约束（取决于这些属性中的任何一个是否是唯一的：Sector）。

另外，你在整个查询中的几个地方做了一件奇怪的事情，如下所示：

MATCH (s {identifier:line.CODE_SBRICK}),(r{identifier:line.CODE_TER})

你在MATCH中使用的变量已经绑定了，所以我建议使用WHERE子句来表明这是一个过滤步骤：

WITH s,c,r,line
WHERE s.identifier = line.CODE_SBRICK AND r.identifier = line.CODE_TER

也就是说，在所有这些情况下，您已经明确地将这些属性设置为相关的行属性，因此无需执行此类过滤，这是不必要的。我建议删除那些匹配，然后合并关系。

如何优化此cypher查询以获得更快的结果

1 个答案: