Sql GroupBy在Google BigQuery中获取不同的行需要更长的时间
我正在对Google BigQuery中的publicdata:samples.github_timeline数据集进行漏斗分析。我想按时间顺序提取所有执行了一系列三个事件的唯一用户 事件及其顺序: 监视事件 推送事件 CreateEvent 以下是查询:Sql GroupBy在Google BigQuery中获取不同的行需要更长的时间,sql,google-bigquery,Sql,Google Bigquery,我正在对Google BigQuery中的publicdata:samples.github_timeline数据集进行漏斗分析。我想按时间顺序提取所有执行了一系列三个事件的唯一用户 事件及其顺序: 监视事件 推送事件 CreateEvent 以下是查询: select user from ( SELECT user1 as user, ts1 as eventDate1, ts2 as eventDate2, IF(ts2 <
select user from (
SELECT user1 as user,
ts1 as eventDate1,
ts2 as eventDate2,
IF(ts2 < ts3, ts3, NULL) as eventDate3
FROM
(SELECT user1,
ts1,
ts2,
ts3
FROM (SELECT user1,
ts1,
IF(ts1 < ts2, ts2, NULL) as ts2
FROM
(SELECT user1,
ts1,
ts2
FROM (SELECT repository_owner as user1,
created_at as ts1
FROM [publicdata:samples.github_timeline]
WHERE type = "WatchEvent") as step1
LEFT JOIN EACH (SELECT repository_owner as user2,
created_at as ts2
FROM [publicdata:samples.github_timeline]
WHERE type = "PushEvent") as step2
ON user1 = user2 where ts1 is not NULL)
) as steps1_2
LEFT JOIN (SELECT repository_owner as user3,
created_at as ts3
FROM [publicdata:samples.github_timeline]
WHERE type = "CreateEvent") as step3
ON user1 = user3
where ts2 is not NULL
)
)
where eventDate3 is not null
group by user
limit 100
如果最后没有按用户分组,速度相当快,只有10秒。但是当我加上它的时候,需要花很多时间才能在20分钟内完成
这个问题怎么了?
您可以在此处测试查询:如果在非分组查询中使用limit 100,orchestrator将在获取前100个数据行后中断执行
group by user limit 100要求在分组之前必须计算所有数据行。然后执行分组。最后,所有限制100生效。你有一个加入爆炸;也就是说,如果用户A有20个WatchEvents、20个PushEvents和20个CreateEvents,那么您的查询可以在这60行中生成8000行。这是因为当连接的两侧都有多个匹配关键点时,它会生成两侧的笛卡尔积。您可以通过使用最短匹配时间来解决此问题,因此您只需查看用户的最短WatchEvent时间以查找后续PushEvent时间,然后查看晚于WatchEvent时间的最短PushEvent时间以查找匹配的CreateEvent时间 下面是一个大约20秒钟内运行的查询:
SELECT user
FROM (
SELECT step2_2.user1 as user,
MIN(step2_2.ts1) as eventDate1,
MIN(step2_2.ts2) as eventDate2,
MIN(step3.ts3) as eventDate3
FROM (
SELECT user1, MIN(ts1) as ts1, MIN(ts2) as ts2
FROM (
SELECT repository_owner as user1,
MIN(created_at) as ts1
FROM [publicdata:samples.github_timeline]
WHERE type = "WatchEvent"
GROUP EACH BY user1) as step1
JOIN EACH (
SELECT repository_owner as user2,
created_at as ts2
FROM [publicdata:samples.github_timeline]
WHERE type = "PushEvent") as step2
ON user1 = user2
WHERE ts1 < ts2
GROUP EACH BY user1
) as step2_2
JOIN EACH (
SELECT repository_owner as user3,
created_at as ts3
FROM [publicdata:samples.github_timeline]
WHERE type = "CreateEvent") as step3
ON user1 = user3
WHERE step2_2.ts2 < step3.ts3
GROUP EACH BY user
)
GROUP BY user
LIMIT 100
如果您的数据集不是太大,您可以使用lead window函数来查找序列并完全避免连接
Select repository_owner
FROM
(
Select repository_owner,type as Event0,
LEAD(x,1) OVER(Partition by repository_owner order by ts) as Event1,
LEAD(x,2) OVER(Partition by repository_owner order by ts) as Event2,
FROM
(
SELECT repository_owner as user,created_at as ts,type as x
from [publicdata:samples.github_timeline]
where type in ("WatchEvent","PushEvent","CreateEvent")
))
where Event0="WatchEvent"
and Event1="PushEvent"
and Event2="CreateEvent"
Group by repository_owner
7秒
如果事件的顺序与约旦的评论不一致,则需要将其变得更加复杂:
Select repository_owner from
(
Select repository_owner,Event0,Event1,
Lead(Event0,1) OVER (Partition by repository_owner order by ts) as Event2,
Lead(Event1,1) OVER (Partition by repository_owner order by ts) as Event3,
FROM
(Select * from
(Select repository_owner,type as Event0,ts,
LEAD(x,1) OVER(Partition by repository_owner order by ts) as Event1,
FROM
(
SELECT repository_owner as user,created_at as ts,type as x
from [publicdata:samples.github_timeline]
where type in ("WatchEvent","PushEvent","CreateEvent")
))
where (Event0="WatchEvent" and
Event1 in("PushEvent" ,"CreateEvent"))
OR ( Event1="CreateEvent" and
Event0 in("PushEvent" ,"WatchEvent")))
)
Where Event0="WatchEvent" and
(Event1="PushEvent" Or Event2="PushEvent") and
Event3="CreateEvent"
Group by repository_owner
如果数据集太大,则会遇到以下问题:
希望它能有所帮助我已经尝试了100次,用了23分钟。我认为这个解决方案比我建议的解决方案更优雅,但这是否只有在这些事件以这种顺序连续发生时才有效?例如,如果有一个WatchEvent/PushEvent/WatchEvent/CreateEvent,这是否会失败?编辑了我的答案,为您提到的场景添加了一个解决方案。