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From Jason Wee <peich...@gmail.com>
Subject Re: multiget_slice SlicePredicate
Date Mon, 17 Dec 2012 09:05:56 GMT
if you have rows like 10k and get 100 column per row, this gonna choke the
cluster...been there. if you really still have to use multiget_slice, try
slice your data before calling multiget_slice and check if your cluster
read request pending increase... try to slow down the client sending
request to the cluster if the pending going up. :)


On Tue, Dec 11, 2012 at 6:15 AM, Wei Zhu <wz1975@yahoo.com> wrote:

> Well, not sure how parallel is multiget. Someone is saying it's in
> parallel sending requests to the different nodes and on each node it's
> executed sequentially. I didn't bother looking into the source code yet.
> Anyone knows it for sure?
>
> I am using Hector, just copied the thrift definition from Cassandra site
> for reference.
>
> You are right, the count is for each individual row.
>
> Thanks.
> -Wei
>
>   ------------------------------
> *From:* "Hiller, Dean" <Dean.Hiller@nrel.gov>
> *To:* "user@cassandra.apache.org" <user@cassandra.apache.org>; Wei Zhu <
> wz1975@yahoo.com>
> *Sent:* Monday, December 10, 2012 1:13 PM
> *Subject:* Re: multiget_slice SlicePredicate
>
> What's wrong with multiget…parallel performance is great from multiple
> disks and so usually that is a good thing.
>
> Also, something looks wrong, since you have list<binary> keys, I would
> expect the Map to be Map<binary, list<ColumnOrSuperColumn>>
>
> Are you sure you have that correct?  IF you set range to 100, it should be
> 100 columns each row but it never hurts to run the code and verify.
>
> Later,
> Dean
> PlayOrm Developer
>
>
> From: Wei Zhu <wz1975@yahoo.com<mailto:wz1975@yahoo.com>>
> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>, Wei Zhu <
> wz1975@yahoo.com<mailto:wz1975@yahoo.com>>
> Date: Monday, December 10, 2012 2:07 PM
> To: Cassandr usergroup <user@cassandra.apache.org<mailto:
> user@cassandra.apache.org>>
> Subject: multiget_slice SlicePredicate
>
> I know it's probably not a good idea to use multiget, but for my use case,
> it's the only choice,
>
> I have question regarding the SlicePredicate argument of the multiget_slice
>
>
> The SlicePredicate takes slice_range which takes start, end and range. I
> suppose start and end will apply to each individual row. How about range,
> is it a accumulative column count of all the rows or to the individual row?
> If I set range to 100, is it 100 columns per row, or total?
>
> Thanks for you reply,
> -Wei
>
> multiget_slice
>
> *
> map<string,list<ColumnOrSuperColumn>> multiget_slice(list<binary> keys,
> ColumnParent column_parent, SlicePredicate predicate, ConsistencyLevel
> consistency_level)
>
>
>
>
>

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