Re: [Bigdata-developers] After a timeout I get only timeouts

[Michael S. <ms...@me...>]

Hi Daniel,

if GC is really the bootleneck, you should verify that

1.) Swapping is disabled: sudo swapoff -a
2.) Swappiness is set to zero: http://askubuntu.com/questions/103915/how-do-i-configure-swappiness

If that doesn’t help, you should try to understand in more detail what’s going on, I’d recommend running vmstat and jstat during your run and correlating the counters to your configuration:

a.) vmstat -n 30 > vmstat.log, for instance, plots a vmstat output every 30s (containing information about memory, disk reads, CPU utilisation and the like)
b.) For jstat, you need to pass in the PID as an argument (see http://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html), I’d recommend jstat -gc or jstat -gcutil

Then try correlate your values to the point in time when the timeout occurs.

Best,
Michael



> On 24 Apr 2016, at 18:47, Daniel Hernández <da...@de...> wrote:
> 
> First I run 30 queries and I got a timeout around query 20. With the option -XX:+UseG1GC I have solved issue. Then I increment the number of queries to 300. Now I got the first timeout around query 100. So the problem continues.
> 
> The issue is not with queries. Queries are not complex. Most of them end in one second.
> Also, I shuffle them in each experiment. The behavior is always the same, there is an instant after that all queries get timeout.
> 
> Now I'm reading the GC documentation and testing with different parameters.
> 
> Cheers,
> Daniel
> 
> El 24/04/16 a las 13:14, Bryan Thompson escribió:
>> Great. However, if this was GC overhead, then there is likely a remaining issue with the queries or the configuration.  I would not expect normal queries to incur that kind of GC overhead.
>> 
>> Thanks,
>> Bryan
>> 
>> On Sun, Apr 24, 2016 at 12:12 PM, Daniel Hernández <da...@de...> wrote:
>> I solved the problem of timeouts. The issue was generated by the garbage
>> collector. I used the option  -XX:+UseG1GC that is documented here:
>> 
>> http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html#G1Options
>> 
>> 
>> Thanks to all!
>> Daniel
>> 
>> 
>> ------------------------------------------------------------------------------
>> Find and fix application performance issues faster with Applications Manager
>> Applications Manager provides deep performance insights into multiple tiers of
>> your business applications. It resolves application problems quickly and
>> reduces your MTTR. Get your free trial!
>> https://ad.doubleclick.net/ddm/clk/302982198;130105516;z
>> _______________________________________________
>> Bigdata-developers mailing list
>> Big...@li...
>> https://lists.sourceforge.net/lists/listinfo/bigdata-developers
>> 
> 
> ------------------------------------------------------------------------------
> Find and fix application performance issues faster with Applications Manager
> Applications Manager provides deep performance insights into multiple tiers of
> your business applications. It resolves application problems quickly and
> reduces your MTTR. Get your free trial!
> https://ad.doubleclick.net/ddm/clk/302982198;130105516;z_______________________________________________
> Bigdata-developers mailing list
> Big...@li...
> https://lists.sourceforge.net/lists/listinfo/bigdata-developers