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Re: 答复: GC pause issues
Generally, the larger the flush to harder the GC will work. Flush more
often to avoid this. What is your total heap size set at?
On Jan 24, 2013 9:02 PM, "Varun Sharma" <[EMAIL PROTECTED]> wrote:

> I do have significant block cache churn and this issue is typical
> correlated with a huge increase in read latencies - could that be the
> reason for this - mslab should be taking care of the memstore related heap
> fragmentation ? Has anyone seen issues with block cache churn ?
>
> On Thu, Jan 24, 2013 at 6:30 PM, Varun Sharma <[EMAIL PROTECTED]> wrote:
>
> > I am curious how reducing the memstore size would help - I have 6 regions
> > and 3G total for memstore - so I would like max out on that by having a
> > bigger flush size per region. Are you asking me to have more regions and
> > smaller memstore flush size instead ? How is that likely to help
> >
> >
> > On Thu, Jan 24, 2013 at 6:07 PM, 谢良 <[EMAIL PROTECTED]> wrote:
> >
> >> Hi Varun,
> >>
> >> Please note if you try to increase new generation size, then the
> "ParNew"
> >> time will be up accordingly, and CMS YGC is also a STW.
> >> could you have a try to reduce memstore size to a smaller value, e.g.
> >> 128m or 256m ?
> >>
> >> Regards,
> >> Liang
> >> ________________________________________
> >> 发件人: Varun Sharma [[EMAIL PROTECTED]]
> >> 发送时间: 2013年1月25日 1:40
> >> 收件人: [EMAIL PROTECTED]
> >> 主题: GC pause issues
> >>
> >> Hi,
> >>
> >> I have a region server which has the following logs. As you can see from
> >> the log, ParNew is sufficiently big (450M) and there are heavy writes
> >> going
> >> in. I am seeing 200ms pauses which eventually build up and there is a
> >> promotion failure. There is a parnew collection every 2-3 seconds so it
> >> fills up real fast. My memstore size is bigger 512m for flushes and 4
> >> regions per server. (overall size is 3G for all memstores) - I have
> mslab
> >> enabled
> >>
> >> 2013-01-24T13:08:16.870+0000: 63533.964: [GC 63533.964: [ParNew:
> >> 471841K->52416K(471872K), 0.2251880 secs] 8733008K->8445039K(12727104K),
> >> 0.2254100 secs] [Times: user=0.50 sys=0.18, real=0.22 secs]
> >> 2013-01-24T13:08:19.546+0000: 63536.639: [GC 63536.639: [ParNew:
> >> 461593K->52416K(471872K), 0.2812690 secs] 8854216K->8557572K(12727104K),
> >> 0.2814870 secs] [Times: user=0.66 sys=0.09, real=0.29 secs]
> >> 013-01-24T13:08:21.824+0000: 63538.917: [GC 63538.918: [ParNew:
> >> 442836K->52416K(471872K), 0.2781490 secs] 8947992K->8705355K(12727104K),
> >> 0.2783810 secs] [Times: user=0.58 sys=0.14, real=0.28 secs]
> >> 2013-01-24T13:08:22.122+0000: 63539.216: [GC [1 CMS-initial-mark:
> >> 8652939K(12255232K)] 8752914K(12727104K), 0.0365000 secs] [Times:
> >> user=0.02
> >> sys=0.00, real=0.04 secs]
> >> 2013-01-24T13:08:22.159+0000: 63539.253: [CMS-concurrent-mark-start]
> >> 2013-01-24T13:08:24.953+0000: 63542.047: [GC 63542.047: [ParNew:
> >> 471872K->52251K(471872K), 0.1611970 secs] 9124811K->8831437K(12727104K),
> >> 0.1614180 secs] [Times: user=0.37 sys=0.19, real=0.16 secs]
> >> 2013-01-24T13:08:26.434+0000: 63543.527: [CMS-concurrent-mark:
> 4.105/4.268
> >> secs] [Times: user=5.36 sys=0.34, real=4.27 secs]
> >> 2013-01-24T13:08:26.434+0000: 63543.527: [CMS-concurrent-preclean-start]
> >> 2013-01-24T13:08:26.597+0000: 63543.691: [CMS-concurrent-preclean:
> >> 0.133/0.163 secs] [Times: user=0.16 sys=0.05, real=0.17 secs]
> >> 2013-01-24T13:08:26.597+0000: 63543.691:
> >> [CMS-concurrent-abortable-preclean-start]
> >> 2013-01-24T13:08:27.401+0000: 63544.495:
> >> [CMS-concurrent-abortable-preclean: 0.792/0.804 secs] [Times: user=1.46
> >> sys=0.16, real=0.80 secs]
> >> 2013-01-24T13:08:27.403+0000: 63544.496: [GC[YG occupancy: 274458 K
> >> (471872
> >> K)]63544.496: [Rescan (parallel) , 0.0540730 secs]63544.551: [weak refs
> >> processing, 0.0001700 secs] [1 CMS-remark: 8779186K(12255232K)]
> >> 9053645K(12727104K), 0.0544410 secs] [Times: user=0.20 sys=0.01,
> real=0.06
> >> secs]
> >> 2013-01-24T13:08:27.458+0000: 63544.551: [CMS-concurrent-sweep-start]