[jira] [Work started] (IMPALA-7115) Set a default THREAD_RESERVATION_LIMIT value

["Tim Armstrong (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-7115?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Work on IMPALA-7115 started by Tim Armstrong.
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> Set a default THREAD_RESERVATION_LIMIT value
> --------------------------------------------
>
>                 Key: IMPALA-7115
>                 URL: https://issues.apache.org/jira/browse/IMPALA-7115
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Backend
>            Reporter: Tim Armstrong
>            Assignee: Tim Armstrong
>            Priority: Major
>              Labels: resource-management
>
> As a follow on to IMPALA-6035, we should set a default value that actually will help protect again insanely complex queries.
> Motivating discussion is here: https://gerrit.cloudera.org/#/c/10365/9/common/thrift/ImpalaInternalService.thrift
> {quote}
> Tim Armstrong
> 1:11 PM
> Dan suggested setting a default here. I started doing some experiments to see what our current practical limits are.
> On stock Ubuntu 16.04 I start getting thread_resource_error at around 8000 reserved threads. I'm not sure that the config reflects what people would use on production systems so continuing to investigate.
> Dan Hecht
> 1:31 PM
> We could also consider choosing a default dynamically based on the OS's setting, if that's necessary.
> Tim Armstrong
> 3:45 PM
> I increased some of the configs (I think I was limited by /sys/fs/cgroup/pids/user.slice/user-1000.slice/pids.max == 12288) and now it got oom-killed at ~26000 threads.
> I think unfortunately there are a lot of different OS knobs that impact this and they seem to evolve over time, so it's probably not feasible with a reasonable amount of effort to get it working on all common Linux distros.
> I was thinking ~5000, since 1000-2000 plan nodes is the most I've seen for a query running successfully in production.
> Maybe I should do this in a follow-on change, since we probably also want to add a test query at or near this limit.
> {quote}



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