密码2不将架构索引与OR运算符配合使用 [英] Cypher 2 not using schema index with OR operator
本文介绍了密码2不将架构索引与OR运算符配合使用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
给出的是Neo4j 2.1.7的以下图形:
Given is the following graph for Neo4j 2.1.7:
CREATE
(:Application {Name: "Test Application", Aliases: ["Test", "App", "TestProject"]}),
(:Application {Name: "Another Application", Aliases: ["A-App", "XYZ", "XYProject"]}),
(:Application {Name: "Database X", Aliases: ["DB-App", "DB", "DB-Project"]}),
(:System {Name: "Server1", Application: "TestProject"}),
(:System {Name: "Server2", Application: "Test Application"}),
(:System {Name: "Server3", Application: "another App"}),
(:System {Name: "Server4", Application: "Some Database"}),
(:System {Name: "Server5", Application: "App"}),
(:System {Name: "Server6", Application: "App XY"}),
(:System {Name: "Server7", Application: "App DB"}),
(:System {Name: "Server8", Application: "Test"}),
(:System {Name: "Server9", Application: "TestProject"}),
(:System {Name: "Server10", Application: "test"}),
(:System {Name: "Server11", Application: "App XY"});
CREATE INDEX ON :Application(Name);
CREATE INDEX ON :Application(Aliases);
CREATE INDEX ON :System(Application);
以下查询正在使用架构索引:
PROFILE
MATCH (a:Application { Name: "Test Application" })
MATCH (s:System)
WHERE s.Application = a.Name
RETURN a,s;
neo4j-sh (?)$ PROFILE MATCH (a:Application { Name: "Test Application" }) MATCH (s:System) WHERE s.Application = a.Name RETURN a,s;
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | a | s |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[4]{Name:"Server2",Application:"Test Application"} |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> 1 row
==>
==> SchemaIndex(0)
==> |
==> +SchemaIndex(1)
==>
==> +----------------+------+--------+-------------+-------------------------------------------+
==> | Operator | Rows | DbHits | Identifiers | Other |
==> +----------------+------+--------+-------------+-------------------------------------------+
==> | SchemaIndex(0) | 1 | 4 | s, s | Property(a,Name(0)); :System(Application) |
==> | SchemaIndex(1) | 1 | 2 | a, a | { AUTOSTRING0}; :Application(Name) |
==> +----------------+------+--------+-------------+-------------------------------------------+
==>
==> Total database accesses: 6
-
PROFILE
MATCH (a:Application { Name: "Test Application" })
MATCH (s:System)
WHERE s.Application IN a.Aliases
RETURN a,s;
neo4j-sh (?)$ PROFILE MATCH (a:Application { Name: "Test Application" }) MATCH (s:System) WHERE s.Application IN a.Aliases RETURN a,s;
==> +----------------------------------------------------------------------------------------------------------------------------+
==> | a | s |
==> +----------------------------------------------------------------------------------------------------------------------------+
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[10]{Name:"Server8",Application:"Test"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[7]{Name:"Server5",Application:"App"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[3]{Name:"Server1",Application:"TestProject"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[11]{Name:"Server9",Application:"TestProject"} |
==> +----------------------------------------------------------------------------------------------------------------------------+
==> 4 rows
==>
==> SchemaIndex(0)
==> |
==> +SchemaIndex(1)
==>
==> +----------------+------+--------+-------------+----------------------------------------------+
==> | Operator | Rows | DbHits | Identifiers | Other |
==> +----------------+------+--------+-------------+----------------------------------------------+
==> | SchemaIndex(0) | 4 | 9 | s, s | Property(a,Aliases(1)); :System(Application) |
==> | SchemaIndex(1) | 1 | 2 | a, a | { AUTOSTRING0}; :Application(Name) |
==> +----------------+------+--------+-------------+----------------------------------------------+
==>
==> Total database accesses: 11
与OR运算符结合使用时不是:
PROFILE
MATCH (a:Application { Name: "Test Application"})
MATCH (s:System)
WHERE s.Application = a.Name OR s.Application IN a.Aliases
RETURN a,s;
neo4j-sh (?)$ PROFILE MATCH (a:Application { Name: "Test Application"}) MATCH (s:System) WHERE s.Application = a.Name OR s.Application IN a.Aliases RETURN a,s;
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | a | s |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[3]{Name:"Server1",Application:"TestProject"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[4]{Name:"Server2",Application:"Test Application"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[7]{Name:"Server5",Application:"App"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[10]{Name:"Server8",Application:"Test"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[11]{Name:"Server9",Application:"TestProject"} |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> 5 rows
==>
==> Filter
==> |
==> +NodeByLabel
==> |
==> +SchemaIndex
==>
==> +-------------+------+--------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------+
==> | Operator | Rows | DbHits | Identifiers | Other |
==> +-------------+------+--------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------+
==> | Filter | 5 | 126 | | (Property(s,Application(2)) == Property(a,Name(0)) OR any(-_-INNER-_- in Property(a,Aliases(1)) where Property(s,Application(2)) == -_-INNER-_-)) |
==> | NodeByLabel | 11 | 12 | s, s | :System |
==> | SchemaIndex | 1 | 2 | a, a | { AUTOSTRING0}; :Application(Name) |
==> +-------------+------+--------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------+
==>
==> Total database accesses: 140
但这一项有效吗?
PROFILE
MATCH (a:Application { Name: "Test Application"})
MATCH (s:System)
WHERE s.Application IN (a.Aliases + a.Name)
RETURN a,s;
neo4j-sh (?)$ PROFILE MATCH (a:Application { Name: "Test Application"}) MATCH (s:System) WHERE s.Application IN (a.Aliases + a.Name) RETURN a,s;
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | a | s |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[10]{Name:"Server8",Application:"Test"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[7]{Name:"Server5",Application:"App"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[3]{Name:"Server1",Application:"TestProject"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[11]{Name:"Server9",Application:"TestProject"} |
==> | Node[0]{Name:"Test Application",Aliases:["Test","App","TestProject"]} | Node[4]{Name:"Server2",Application:"Test Application"} |
==> +--------------------------------------------------------------------------------------------------------------------------------+
==> 5 rows
==>
==> SchemaIndex(0)
==> |
==> +SchemaIndex(1)
==>
==> +----------------+------+--------+-------------+-----------------------------------------------------------------------+
==> | Operator | Rows | DbHits | Identifiers | Other |
==> +----------------+------+--------+-------------+-----------------------------------------------------------------------+
==> | SchemaIndex(0) | 5 | 13 | s, s | Add(Property(a,Aliases(1)),Property(a,Name(0))); :System(Application) |
==> | SchemaIndex(1) | 1 | 2 | a, a | { AUTOSTRING0}; :Application(Name) |
==> +----------------+------+--------+-------------+-----------------------------------------------------------------------+
==>
==> Total database accesses: 15
为什么带有OR运算符的查询不使用新索引?
Why is the query with OR operator not using the new indexes?
推荐答案
因为重写器不够聪明，无法识别这种极端情况.
Because the rewriter is not smart enough to recognize this corner case.
您已经回答了您自己的问题，我也会建议您回答.
You already answered your own question, with which I would have also suggested.
PROFILE
MATCH (a:Application { Name: "Test Application"})
MATCH (s:System)
WHERE s.Application IN (a.Aliases + a.Name)
RETURN a,s;
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