Question

我正在进行公交时刻表搜索。我创建了一些简单的数据进行测试：10辆公交车，每辆公交车有2-5个时刻表，每个时刻表有一个位置关系如下：

bus-[:SCHEDULED]->(schedule)-[scheduleLocation :ORIGIN|TRANSIT|DESTINATION]->location

我想在指定的时间范围内在指定的位置搜索星期一的公交车，我想知道为什么需要很长时间来运行查询（超过10秒）。

以下是查询：

MATCH bus-[:SCHEDULED]->(schedule)-[scheduleLocation :ORIGIN|TRANSIT|DESTINATION]->location
where location.code! = 'KING' AND 
(
(bus.runsOnMonday = true AND ((specifiedScheduleLocation.arrivalTime! >='+00:00:16:00' OR specifiedScheduleLocation.departTime! >='+00:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+00:14:42:00' OR specifiedScheduleLocation.departTime! <='+00:14:42:00')))
OR (bus.runsOnTuesday = true AND ((specifiedScheduleLocation.arrivalTime! >='+06:00:16:00' OR specifiedScheduleLocation.departTime! >='+06:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+06:14:41:00' OR specifiedScheduleLocation.departTime! <='+06:14:41:00')))
OR (bus.runsOnWednesday = true AND ((specifiedScheduleLocation.arrivalTime! >='+05:00:16:00' OR specifiedScheduleLocation.departTime! >='+05:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+05:14:41:00' OR specifiedScheduleLocation.departTime! <='+05:14:41:00')))
OR (bus.runsOnThursday = true AND ((specifiedScheduleLocation.arrivalTime! >='+04:00:16:00' OR specifiedScheduleLocation.departTime! >='+04:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+04:14:41:00' OR specifiedScheduleLocation.departTime! <='+04:14:41:00')))
OR (bus.runsOnFriday = true AND ((specifiedScheduleLocation.arrivalTime! >='+03:00:16:00' OR specifiedScheduleLocation.departTime! >='+03:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+03:14:41:00' OR specifiedScheduleLocation.departTime! <='+03:14:41:00')))
OR (bus.runsOnSaturday = true AND ((specifiedScheduleLocation.arrivalTime! >='+02:00:16:00' OR specifiedScheduleLocation.departTime! >='+02:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+02:14:41:00' OR specifiedScheduleLocation.departTime! <='+02:14:41:00')))
OR (bus.runsOnSunday = true AND ((specifiedScheduleLocation.arrivalTime! >='+01:00:16:00' OR specifiedScheduleLocation.departTime! >='+01:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+01:14:41:00' OR specifiedScheduleLocation.departTime! <='+01:14:41:00')))
)
return distinct bus,specifiedScheduleLocation

Answer 1

AFAIK查询where where子句基于属性的速度很慢，因为Neo4j必须加载所有匹配的节点/关系，然后扫描其属性以过滤它们。

为了获得更好的结果，您可能希望将属性移动到节点和关系中，并尝试仅通过基于关系路径和节点标签过滤路径来查找结果。

也许最明显的例子是使用时间树而不是时间戳属性（link）。

如果您不需要管理特定日期，即星期几和时间，则可以为一周中的每一天设置24小时时间树。

Answer 2

地点有标签吗？如果没有，请给它贴上标签Location，然后运行

CREATE INDEX ON :Location(code)

等待几秒钟/分钟（取决于数据库的大小）。

然后将查询更改为：

MATCH bus-[:SCHEDULED]->(schedule)-[scheduleLocation :ORIGIN|TRANSIT|DESTINATION]->(location:Location {code:'KING'})
where (
(bus.runsOnMonday = true AND ((specifiedScheduleLocation.arrivalTime! >='+00:00:16:00' OR specifiedScheduleLocation.departTime! >='+00:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+00:14:42:00' OR specifiedScheduleLocation.departTime! <='+00:14:42:00')))
OR (bus.runsOnTuesday = true AND ((specifiedScheduleLocation.arrivalTime! >='+06:00:16:00' OR specifiedScheduleLocation.departTime! >='+06:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+06:14:41:00' OR specifiedScheduleLocation.departTime! <='+06:14:41:00')))
OR (bus.runsOnWednesday = true AND ((specifiedScheduleLocation.arrivalTime! >='+05:00:16:00' OR specifiedScheduleLocation.departTime! >='+05:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+05:14:41:00' OR specifiedScheduleLocation.departTime! <='+05:14:41:00')))
OR (bus.runsOnThursday = true AND ((specifiedScheduleLocation.arrivalTime! >='+04:00:16:00' OR specifiedScheduleLocation.departTime! >='+04:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+04:14:41:00' OR specifiedScheduleLocation.departTime! <='+04:14:41:00')))
OR (bus.runsOnFriday = true AND ((specifiedScheduleLocation.arrivalTime! >='+03:00:16:00' OR specifiedScheduleLocation.departTime! >='+03:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+03:14:41:00' OR specifiedScheduleLocation.departTime! <='+03:14:41:00')))
OR (bus.runsOnSaturday = true AND ((specifiedScheduleLocation.arrivalTime! >='+02:00:16:00' OR specifiedScheduleLocation.departTime! >='+02:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+02:14:41:00' OR specifiedScheduleLocation.departTime! <='+02:14:41:00')))
OR (bus.runsOnSunday = true AND ((specifiedScheduleLocation.arrivalTime! >='+01:00:16:00' OR specifiedScheduleLocation.departTime! >='+01:00:16:00') AND (specifiedScheduleLocation.arrivalTime! <='+01:14:41:00' OR specifiedScheduleLocation.departTime! <='+01:14:41:00')))
)
return distinct bus,specifiedScheduleLocation

最后，如果有帮助，请告诉我们！它应该，因为您当前的查询扫描整个图形 - 它没有固定的具体节点。

干杯

Cypher对小型数据库的性能降低

2 个答案: