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From Voytek Jarnot <voytek.jar...@gmail.com>
Subject Re: Very odd & inconsistent results from SASI query
Date Mon, 20 Mar 2017 20:52:11 GMT
Apologies for the stream-of-consciousness replies, but are the dropped
message stats output by tpstats an accumulation since the node came up, or
are there processes which clear and/or time-out the info?

On Mon, Mar 20, 2017 at 3:18 PM, Voytek Jarnot <voytek.jarnot@gmail.com>
wrote:

> No dropped messages in tpstats on any of the nodes.
>
> On Mon, Mar 20, 2017 at 3:11 PM, Voytek Jarnot <voytek.jarnot@gmail.com>
> wrote:
>
>> Appreciate the reply, Kurt.
>>
>> I sanitized it out of the traces, but all trace outputs listed the same
>> node for all three queries (1 working, 2 not working). Read repair chance
>> set to 0.0 as recommended when using TWCS.
>>
>> I'll check tpstats - in this environment, load is not an issue, but
>> network issues may be.
>>
>> On Mon, Mar 20, 2017 at 2:42 PM, kurt greaves <kurt@instaclustr.com>
>> wrote:
>>
>>> As secondary indexes are stored individually on each node what you're
>>> suggesting sounds exactly like a consistency issue. the fact that you read
>>> 0 cells on one query implies the node that got the query did not have any
>>> data for the row. The reason you would sometimes see different behaviours
>>> is likely because of read repairs. The fact that the repair guides the
>>> issue pretty much guarantees it's a consistency issue.
>>>
>>> You should check for dropped mutations in tpstats/logs and if they are
>>> occurring try and stop that from happening (probably load related). You
>>> could also try performing reads and writes at LOCAL_QUORUM for stronger
>>> consistency, however note this has a performance/latency impact.
>>>
>>>
>>>
>>
>

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