Re: Discrepancy between process and memory information in crashdump
Anshul Mittal <[email protected]>
| Newsgroups | gmane.comp.lang.erlang.general |
|---|---|
| Message-ID | <CABz1FgZTR-ib-dD0p-H_D8t-xGWt+K7rZBRc55FJu_ydhwok_Q@mail.gmail.com> |
In that case, won't the memory reported in the "Memory" tab also be lesser (post garbage collection)? Cheers, Anshul Mittal On Thu, Aug 13, 2020 at 7:34 AM Fred Hebert <[email protected]> wrote: > From what I recall seeing, the crash dump, before being produced, has what > looks like garbage collection running to eliminate some of the stale data. > > So if the node runs out of memory because it has a lot of garbage, you > unfortunately can't see post-facto, and you have to kind of catch it live > to analyze what is going on. > > Regards, > Fred. > > On Thu, Aug 13, 2020 at 12:40 AM Anshul Mittal <[email protected]> > wrote: > >> Hi, >> I have a prod BEAM running on OTP 22 . I recently saw a crash in prod, >> which generated a crash dump. The memory consumption of the process jumped >> rapidly from ~5G to ~40G within a matter of a couple of minutes. >> >> Slogan: eheap_alloc: Cannot allocate 6664208 bytes of memory (of type >> "old_heap"). >> System version: Erlang/OTP 22 [erts-10.7.1] [source-471fe20989] [64-bit] >> [smp:36:36] [ds:36:36:10] [async-threads:1] [frame-pointer] >> >> When I analyzed the crash dump in the crash dump viewer, it shows the >> following summary on the memory tab: >> >> Total: 50 GB >> Processes: 42 GB >> Processes Used: 42 GB >> System: 7728 MB >> ... >> >> However, when I sum the "Memory: " information from the individual >> process entries in the crash dump, it only adds up to ~3G . >> >> I do see some processes with "WARNING: This process has an incomplete >> heap. Some information might be missing. " However, from what I can tell >> from the code here: https://fburl.com/ye99sjs9 , this warning means that >> reference counted binaries are missing from the crash dump, and not the >> information about the process heap itself. >> >> The crashdump itself doesn't seem to be truncated (don't see any such >> message on the "General Information" tab in the viewer). >> >> What could explain the discrepancy here? >> >> >> Cheers, >> Anshul Mittal >> >