我一直在尝试使用模式解析进行优化，但越来越困惑。
这是我最初的疑问：
MATCH (a:Actor)-[:ACTED_IN]->(m:Movie)
WHERE 2000 <= m.year <= 2005 AND a.born.year >= 1980
RETURN a.name AS Actor, a.born AS Born,
collect(DISTINCT m.title) AS Movies ORDER BY Actor分析时，我得到：
Cypher version: , planner: COST, runtime: PIPELINED. 41944 total db hits in 152 ms.我试着改写成：
profile MATCH (a:Actor)
WHERE a.born.year >= 1980
// Add a WITH clause to create the list using pattern comprehension
with a
match (a)-[:ACTED_IN]-(m:Movie)
where 2000 <= m.year <= 2005
// filter the result of the pattern comprehension to return only lists with elements
// return the Actor, Born, and Movies
return a.name as Actor, a.born as Born, [(a)-[:ACTED_IN]-(m) | m.title] as Movies
order by a分析时，我得到：
Cypher version: , planner: COST, runtime: PIPELINED. 47879 total db hits in 47 ms.我又试了一次改写：
profile MATCH (a:Actor)
WHERE a.born.year >= 1980
// Add a WITH clause to create the list using pattern comprehension
// filter the result of the pattern comprehension to return only lists with elements
// return the Actor, Born, and Movies
with a, [ (a)-[:ACTED_IN]-(m:Movie) where 2000 <= m.year <= 2005 | m.title] as Movies
return a.name as Actor, a.born as Born, Movies
order by a并且当配置文件获得：
Cypher version: , planner: COST, runtime: PIPELINED. 59251 total db hits in 6 ms.每一次的性能都比前一次差。我可以查看查询计划来了解差异。与使用collect语句的初始查询相比，是否有一种方法可以使用模式理解来实际减少DB命中？
1条答案
按热度按时间balp4ylt1#
请向我们显示您上次查询的配置文件结果;我在电影数据库中测试了它，它与原始查询相比运行良好（46 ms与原始：120 db点击）。另外，检查Actor.born.year是否有索引。