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From Derek Williams <de...@fyrie.net>
Subject Re: Question regarding multi datacenter and LOCAL_QUORUM
Date Wed, 20 Mar 2013 18:49:45 GMT
I'm think I need help with pointing out what the problem is. The log you
posted only contains references to 143, 145, and 146, which all appear to
be in the same datacenter as 146?


On Wed, Mar 20, 2013 at 11:29 AM, Dwight Smith
<Dwight.Smith@genesyslab.com>wrote:

>  Hi ****
>
> ** **
>
> I have 2 data centers – with 3 nodes in each DC – version 1.1.6 -
>  replication factor 2 -  topology properties:****
>
> ** **
>
> # Cassandra Node IP=Data Center:Rack****
>
> xx.yy.zz.143=AZ1:RAC1****
>
> xx.yy.zz.145=AZ1:RAC1****
>
> xx.yy.zz.146=AZ1:RAC1****
>
> xx.yy.zz.147=AZ2:RAC2****
>
> xx.yy.zz.148=AZ2:RAC2****
>
> xx.yy.zz.149=AZ2:RAC2****
>
> ** **
>
> Using LOCAL_QUORUM, my understanding was that reads/writes would process
> locally ( for the coordinator ) and send requests to the remaining nodes in
> the DC, but in the system log for 146 I observe that this is not the case,
> extract from the log:****
>
> ** **
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,312 CassandraServer.java (line 306) get_slice****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,313 ReadCallback.java (line 79) Blockfor is 2; setting
up requests to /xx.yy.zz.146,/xx.yy.zz.143,/xx.yy.zz.145****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,334 CassandraServer.java (line 306) get_slice****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,334 ReadCallback.java (line 79) Blockfor is 2; setting
up requests to /xx.yy.zz.146,/xx.yy.zz.143****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,366 CassandraServer.java (line 306) get_slice****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,367 ReadCallback.java (line 79) Blockfor is 2; setting
up requests to /xx.yy.zz.146,/xx.yy.zz.143,/xx.yy.zz.145****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,391 CassandraServer.java (line 589) batch_mutate****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,418 CassandraServer.java (line 589) batch_mutate****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,429 CassandraServer.java (line 306) get_slice****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,429 ReadCallback.java (line 79) Blockfor is 2; setting
up requests to /xx.yy.zz.146,/xx.yy.zz.145****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,441 CassandraServer.java (line 306) get_slice****
>
> DEBUG [Thrift:1] 2013-03-19 00:00:53,441 ReadCallback.java (line 79) Blockfor is 2; setting
up requests to /xx.yy.zz.146,/xx.yy.zz.143****
>
> ** **
>
> The batch mutates are as expected – locally, two replicas, and hints to DC AZ2, but
why the unexpected behavior for the get_slice requests.  This is observed throughout the log.****
>
> ** **
>
> Thanks much ****
>
> ** **
>
> ** **
>
>  ****
>
> ** **
>



-- 
Derek Williams

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