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Re: 答复: GC pause issues
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]
>> 2013-01-24T13:08:27.955+0000: 63545.048: [GC 63545.049: [ParNew:
>> 471707K->44566K(471872K), 0.1371770 secs] 9044714K->8701862K(12727104K),
>> 0.1374060 secs] [Times: user=0.35 sys=0.12, real=0.14 secs]
>> 2013-01-24T13:08:29.285+0000: 63546.378: [GC 63546.478: [ParNew:
>> 445714K->52416K(471872K), 0.5626120 secs] 8648805K->8410223K(12727104K),