phoenix-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Lars Hofhansl (JIRA)" <>
Subject [jira] [Commented] (PHOENIX-4148) COUNT(DISTINCT(...)) should have a memory size limit
Date Sat, 02 Sep 2017 01:49:00 GMT


Lars Hofhansl commented on PHOENIX-4148:

Hmm... How do I find the tenant id all the way down in DistinctValueWithCountServerAggregator?

Also it seems we're double allocating a bit (unless I am missing something):
* In GroupedAggregateRegionObserver groupByCache we group by the key
* DistinctValueWithCountServerAggregator we group again to get the count

> COUNT(DISTINCT(...)) should have a memory size limit
> ----------------------------------------------------
>                 Key: PHOENIX-4148
>                 URL:
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: Lars Hofhansl
> I just managed to kill (hang) a region server by issuing a COUNT(DISTINCT(...)) query
over a column with very high cardinality (20m in this case).
> This is perhaps not a useful thing to do, but Phoenix should nonetheless not allow to
have a server fail because of a query.
> [~jamestaylor], I see there GlobalMemoryManager, but I do not quite see how I'd get a
reference to one, once needs a tenant id, etc.

This message was sent by Atlassian JIRA

View raw message