Sure sounds like a socket bug, doesn't it? I turn to tcpdump when Solr starts
behaving strangely in a socket-related way. Knowing exactly what's happening at
the transport level is worth a month of guessing and poking.
On Jul 8, 2014, at 3:53 AM, Harald Kirsch <harald.kir...@raytion.com> wrote:
> Hi all,
>
> This is what happens when I run a regular wget query to log the current
> number of documents indexed:
>
> 2014-07-08:07:23:28 QTime=20 numFound="5720168"
> 2014-07-08:07:24:28 QTime=12 numFound="5721126"
> 2014-07-08:07:25:28 QTime=19 numFound="5721126"
> 2014-07-08:07:27:18 QTime=50071 numFound="5721126"
> 2014-07-08:07:29:08 QTime=50058 numFound="5724494"
> 2014-07-08:07:30:58 QTime=50033 numFound="5730710"
> 2014-07-08:07:31:58 QTime=13 numFound="5730710"
> 2014-07-08:07:33:48 QTime=50065 numFound="5734069"
> 2014-07-08:07:34:48 QTime=16 numFound="5737742"
> 2014-07-08:07:36:38 QTime=50037 numFound="5737742"
> 2014-07-08:07:37:38 QTime=12 numFound="5738190"
> 2014-07-08:07:38:38 QTime=23 numFound="5741208"
> 2014-07-08:07:40:29 QTime=50034 numFound="5742067"
> 2014-07-08:07:41:29 QTime=12 numFound="5742067"
> 2014-07-08:07:42:29 QTime=17 numFound="5742067"
> 2014-07-08:07:43:29 QTime=20 numFound="5745497"
> 2014-07-08:07:44:29 QTime=13 numFound="5745981"
> 2014-07-08:07:45:29 QTime=23 numFound="5746420"
>
> As you can see, the QTime is just over 50 seconds at irregular intervals.
>
> This happens independent of whether I am indexing documents with around 20
> dps or not. First I thought about a dependence on the auto-commit of 5
> minutes, but the the 50 seconds hits are too irregular.
>
> Furthermore, and this is *really strange*: when hooking strace on the solr
> process, the 50 seconds QTimes disappear completely and consistently --- a
> real Heisenbug.
>
> Nevertheless, strace shows that there is a socket timeout of 50 seconds
> defined in calls like this:
>
> [pid 1253] 09:09:37.857413 poll([{fd=96, events=POLLIN|POLLERR}], 1, 50000)
> = 1 ([{fd=96, revents=POLLIN}]) <0.000040>
>
> where the fd=96 is the result of
>
> [pid 25446] 09:09:37.855235 accept(122, {sa_family=AF_INET,
> sin_port=htons(57236), sin_addr=inet_addr("ip address of local host")}, [16])
> = 96 <0.000054>
>
> where again fd=122 is the TCP port on which solr was started.
>
> My hunch is that this is communication between the cores of solr.
>
> I tried to search the internet for such a strange connection between socket
> timeouts and strace, but could not find anything (the stackoverflow entry
> from yesterday is my own :-(
>
>
> This smells a bit like a race condition/deadlock kind of thing which is
> broken up by timing differences introduced by stracing the process.
>
> Any hints appreciated.
>
> For completeness, here is my setup:
> - solr-4.8.1,
> - cloud version running
> - 10 shards on 10 cores in one instance
> - hosted on SUSE Linux Enterprise Server 11 (x86_64), VERSION 11, PATCHLEVEL 2
> - hosted on a vmware, 4 CPU cores, 16 GB RAM
> - single digit million docs indexed, exact number does not matter
> - zero query load
>
>
> Harald.
