[英]Cypher Neo4j - Query that uses the clause 'IN' on the collection is very slow
Hi i'm trying to import some data from CSV files in Neo4j 2.3.1 . 嗨,我正在尝试从Neo4j 2.3.1中的 CSV文件导入一些数据。 I've already imported some nodes of type :Author and :Article .
我已经导入了:Author和:Article类型的一些节点。
The Author node is composed of properties like: 作者节点由以下属性组成:
I've also added index on principal_name, alias and key. 我还添加了有关principal_name,别名和键的索引。
The problem comes when I try to import the relationships between nodes of type Article and Author. 当我尝试导入Article和Author类型的节点之间的关系时,就会出现问题。
The CSV has this type of structure: CSV具有以下类型的结构:
articleKey,authorName
Has a naive solution i've tried to create the relationship using a query like this one: 有一个天真的解决方案,我试图使用像这样的查询来创建关系:
USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM "file:///myPath.csv" AS line
MATCH (art:Article{key: line.key1})
MATCH (auth:Author) WHERE line.key2 IN (auth.alias)
CREATE UNIQUE (auth)-[:AUTHOR_OF]->(art);
The query is painfully slow because the second MATCH is really slow as i discovered using the profiler. 查询非常缓慢,因为正如我使用探查器发现的那样,第二个MATCH确实非常慢。 It takes 10-12 seconds to create every relation because i've many Authors in the db(around 1000000).
创建每个关系需要10-12秒 ,因为我在db中有很多Authors(大约1000000)。
So i'm looking for a way to execute a query like this one to get a faster execution(is an example to illustrate the structure that i want to obtain): 因此,我正在寻找一种执行这样的查询的方法以加快执行速度(这是一个示例,说明了我想要获得的结构):
MATCH (auth:Author{principal_name: line.key2})
IF auth null THEN
MATCH (auth:Author) WHERE line.key2 IN (auth.alias)
END
There is a way to do that with Cypher ? 有没有办法用Cypher做到这一点?
If you changed your model so that all of an Author
node's names (both the principal name and all the aliases) are all in separate Name
nodes, like this: 如果更改了模型,以使所有
Author
节点的名称(主体名称和所有别名)都位于单独的Name
节点中,如下所示:
(auth:Author)-[:HAS_NAME]->(name:Name {name: 'Fred McGillicutty'})
Then the query would be simply: 那么查询将很简单:
USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM "file:///myPath.csv" AS line
MATCH
(art:Article { key: line.key1 }),
(auth:Author)-[:HAS_NAME]->(name:Name { name:line.key2 })
CREATE (auth)-[:AUTHOR_OF]->(art);
If you create indexes on :Article(key)
, and :Name(name)
, this query should be very efficient. 如果您在
:Article(key)
和:Name(name)
上创建索引,则此查询应该非常有效。
If many authors have aliases and if you expect to query on these aliases you should model them as nodes. 如果许多作者都有别名,并且您希望查询这些别名,则应将其建模为节点。 I think this will speed up queries for creating relationships and allows for more flexible queries involving aliases.
我认为这将加快创建关系的查询,并允许涉及别名的更灵活的查询。
(:Alias)<-[:HAS]-(:Author)-[:AUTHOR_OF]->(:Article)
Add indexes on all nodes. 在所有节点上添加索引。 If possible use uniqueness constraints .
如果可能,请使用唯一性约束 。
You can now query for Alias
and Author
nodes to add relationships: 现在,您可以查询
Alias
和Author
节点以添加关系:
USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM "file:///myPath.csv" AS line
MATCH (art:Article {key: line.key1})
// get the Author directly or by alias
MATCH (alias:Alias)<-[:HAS]-(auth:Author)
WHERE alias.principal_name = line.key2 OR auth.principal_name = line.key2
CREATE (auth)-[:AUTHOR_OF]->(art)
With indexes the lookups should be pretty fast. 使用索引,查找应该非常快。
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