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HBase >> mail # dev >> Balancer switch runs causing problems


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Re: Balancer switch runs causing problems
But continue to see reads on META - no idea why ?
On Mon, Jan 27, 2014 at 8:52 PM, Varun Sharma <[EMAIL PROTECTED]> wrote:

> We are not seeing any balancer related logs btw anymore...
>
>
> On Mon, Jan 27, 2014 at 8:23 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>
>> Looking at the changes since release 0.94.7, I found:
>>
>> HBASE-8655 Backport to 94 - HBASE-8346(Prefetching .META. rows in case
>> only
>> when useCache is set to true)
>> HBASE-8698 potential thread creation in MetaScanner.metaScan
>>
>> If possible, can you upgrade your cluster ?
>>
>> Cheers
>>
>>
>> On Mon, Jan 27, 2014 at 8:02 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>>
>> > Do you see the following (from
>> > HConnectionManager$HConnectionImplementation#locateRegionInMeta) ?
>> >
>> >             if (LOG.isDebugEnabled()) {
>> >               LOG.debug("locateRegionInMeta parentTable=" +
>> >                 Bytes.toString(parentTable) + ", metaLocation=" +
>> >                 ((metaLocation == null)? "null": "{" + metaLocation +
>> "}")
>> > +
>> >                 ", attempt=" + tries + " of " +
>> >                 this.numRetries + " failed; retrying after sleep of " +
>> >
>> >
>> > On Mon, Jan 27, 2014 at 7:51 PM, Varun Sharma <[EMAIL PROTECTED]>
>> wrote:
>> >
>> >> Actually not sometimes but we are always seeing a large # of .META.
>> reads
>> >> every 5 minutes.
>> >>
>> >>
>> >> On Mon, Jan 27, 2014 at 7:47 PM, Varun Sharma <[EMAIL PROTECTED]>
>> >> wrote:
>> >>
>> >> > The default one with 0.94.7... - I dont see any of those logs. Also
>> we
>> >> > turned off the balancer switch - but looks like sometimes we still
>> see a
>> >> > large number of requests to .META. table every 5 minutes.
>> >> >
>> >> > Varun
>> >> >
>> >> >
>> >> > On Mon, Jan 27, 2014 at 7:37 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>> >> >
>> >> >> In HMaster#balance(), we have (same for 0.94 and 0.96):
>> >> >>
>> >> >>         for (RegionPlan plan: plans) {
>> >> >>           LOG.info("balance " + plan);
>> >> >>
>> >> >> Do you see such log in master log ?
>> >> >>
>> >> >>
>> >> >> On Mon, Jan 27, 2014 at 7:26 PM, Varun Sharma <[EMAIL PROTECTED]>
>> >> >> wrote:
>> >> >>
>> >> >> > We are seeing one other issue with high read latency (p99 etc.) on
>> >> one
>> >> >> of
>> >> >> > our read heavy hbase clusters which is correlated with the
>> balancer
>> >> >> runs -
>> >> >> > every 5 minutes.
>> >> >> >
>> >> >> > If there is no balancing to do, does the balancer only scan the
>> table
>> >> >> every
>> >> >> > 5 minutes - does it do anything on top of that if the regions are
>> >> >> balanced
>> >> >> > ?
>> >> >> >
>> >> >> > Varun
>> >> >> >
>> >> >>
>> >> >
>> >> >
>> >>
>> >
>> >
>>
>
>