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Posted to user@cassandra.apache.org by ro...@gmail.com on 2010/12/25 07:22:41 UTC
Re: Newbie question - fetching multiple columns of differentdatatypes and conversion from byte[]
Can you please point me an example of that or some Hector API documentation?
I am currently using IndexedSliceRangeQuery to filter on a 2ndary index and fetching all columns of the matching rows - using range start/end = null. Can the option you suggest be used with the 2ndry index filtering? I would appreciate very much seeing an example.
Does it make any performance difference whether that conversion is done by Hector/Cass or by the app?
Thanks.
Roshan
---------------------------------------------------
Sent from BlackBerry
-----Original Message-----
From: Jonathan Ellis <jb...@gmail.com>
Date: Sat, 25 Dec 2010 00:05:44
To: user<us...@cassandra.apache.org>
Reply-To: user@cassandra.apache.org
Subject: Re: Newbie question - fetching multiple columns of different
datatypes and conversion from byte[]
Or you can specify the types with the column name instead of doing a slice.
On Fri, Dec 24, 2010 at 11:23 PM, Nate McCall <na...@riptano.com> wrote:
> In the case where you have different value types within the same
> slice, yes, you must handle the conversion yourself and
> ByteBufferSerializer is the easiest way to do that.
>
> On Fri, Dec 24, 2010 at 10:44 PM, Roshan Dawrani
> <ro...@gmail.com> wrote:
>> Hi,
>>
>> I am new to Cassandra and Hector and have a basic question on fetching
>> multiple columns of a row that have mixed data types.
>>
>> So, I am basically doing equivalent of "Select dateCol1, dateCol2,
>> stringCol1, intCol1 from a_table where key in (?, ?, ?...)"
>>
>> My question is do I need to do the conversion of columns from byte[] to
>> Date/String/Int myself after taking out data from the ColumnSlice?
>>
>> For saving the same data, while adding the columns, I was able to tell which
>> serializer to use, but slice queries seem to take only one ValueSerializer
>> for all columns being retrieved. So, if I have got it correctly, I can only
>> use ByteBufferSerializer in the Hector API slice query call and then do
>> further data-type specific conversion myself at the app level?
>>
>> --
>> Roshan
>> Blog: http://roshandawrani.wordpress.com/
>> Twitter: @roshandawrani
>> Skype: roshandawrani
>>
>
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com
Re: Newbie question - fetching multiple columns of differentdatatypes
and conversion from byte[]
Posted by Roshan Dawrani <ro...@gmail.com>.
Thanks a lot for the references. Will check them out first before asking the
next question.
On Sat, Dec 25, 2010 at 6:46 PM, Nate McCall <na...@riptano.com> wrote:
> See the following PDF for some additional detail on hector:
> http://www.riptano.com/sites/default/files/hector-v2-client-doc.pdf
>
> There is a also a project with some basic stand-alone examples that
> may be helpful:
> https://github.com/zznate/hector-examples
>
> And Riptano maintains a Java port of a Twitter example using Hector:
> https://github.com/riptano/twissjava
>
> On Sat, Dec 25, 2010 at 12:22 AM, <ro...@gmail.com> wrote:
> > Can you please point me an example of that or some Hector API
> documentation?
> >
> > I am currently using IndexedSliceRangeQuery to filter on a 2ndary index
> and fetching all columns of the matching rows - using range start/end =
> null. Can the option you suggest be used with the 2ndry index filtering? I
> would appreciate very much seeing an example.
> >
> > Does it make any performance difference whether that conversion is done
> by Hector/Cass or by the app?
> >
> > Thanks.
> > Roshan
> > ---------------------------------------------------
> > Sent from BlackBerry
> >
> > -----Original Message-----
> > From: Jonathan Ellis <jb...@gmail.com>
> > Date: Sat, 25 Dec 2010 00:05:44
> > To: user<us...@cassandra.apache.org>
> > Reply-To: user@cassandra.apache.org
> > Subject: Re: Newbie question - fetching multiple columns of different
> > datatypes and conversion from byte[]
> >
> > Or you can specify the types with the column name instead of doing a
> slice.
> >
> > On Fri, Dec 24, 2010 at 11:23 PM, Nate McCall <na...@riptano.com> wrote:
> >> In the case where you have different value types within the same
> >> slice, yes, you must handle the conversion yourself and
> >> ByteBufferSerializer is the easiest way to do that.
> >>
> >> On Fri, Dec 24, 2010 at 10:44 PM, Roshan Dawrani
> >> <ro...@gmail.com> wrote:
> >>> Hi,
> >>>
> >>> I am new to Cassandra and Hector and have a basic question on fetching
> >>> multiple columns of a row that have mixed data types.
> >>>
> >>> So, I am basically doing equivalent of "Select dateCol1, dateCol2,
> >>> stringCol1, intCol1 from a_table where key in (?, ?, ?...)"
> >>>
> >>> My question is do I need to do the conversion of columns from byte[] to
> >>> Date/String/Int myself after taking out data from the ColumnSlice?
> >>>
> >>> For saving the same data, while adding the columns, I was able to tell
> which
> >>> serializer to use, but slice queries seem to take only one
> ValueSerializer
> >>> for all columns being retrieved. So, if I have got it correctly, I can
> only
> >>> use ByteBufferSerializer in the Hector API slice query call and then do
> >>> further data-type specific conversion myself at the app level?
> >>>
> >>> --
> >>> Roshan
> >>> Blog: http://roshandawrani.wordpress.com/
> >>> Twitter: @roshandawrani
> >>> Skype: roshandawrani
> >>>
> >>
> >
> >
> >
> > --
> > Jonathan Ellis
> > Project Chair, Apache Cassandra
> > co-founder of Riptano, the source for professional Cassandra support
> > http://riptano.com
> >
>
--
Roshan
Blog: http://roshandawrani.wordpress.com/
Twitter: @roshandawrani <http://twitter.com/roshandawrani>
Skype: roshandawrani
Re: Newbie question - fetching multiple columns of differentdatatypes
and conversion from byte[]
Posted by Nate McCall <na...@riptano.com>.
See the following PDF for some additional detail on hector:
http://www.riptano.com/sites/default/files/hector-v2-client-doc.pdf
There is a also a project with some basic stand-alone examples that
may be helpful:
https://github.com/zznate/hector-examples
And Riptano maintains a Java port of a Twitter example using Hector:
https://github.com/riptano/twissjava
On Sat, Dec 25, 2010 at 12:22 AM, <ro...@gmail.com> wrote:
> Can you please point me an example of that or some Hector API documentation?
>
> I am currently using IndexedSliceRangeQuery to filter on a 2ndary index and fetching all columns of the matching rows - using range start/end = null. Can the option you suggest be used with the 2ndry index filtering? I would appreciate very much seeing an example.
>
> Does it make any performance difference whether that conversion is done by Hector/Cass or by the app?
>
> Thanks.
> Roshan
> ---------------------------------------------------
> Sent from BlackBerry
>
> -----Original Message-----
> From: Jonathan Ellis <jb...@gmail.com>
> Date: Sat, 25 Dec 2010 00:05:44
> To: user<us...@cassandra.apache.org>
> Reply-To: user@cassandra.apache.org
> Subject: Re: Newbie question - fetching multiple columns of different
> datatypes and conversion from byte[]
>
> Or you can specify the types with the column name instead of doing a slice.
>
> On Fri, Dec 24, 2010 at 11:23 PM, Nate McCall <na...@riptano.com> wrote:
>> In the case where you have different value types within the same
>> slice, yes, you must handle the conversion yourself and
>> ByteBufferSerializer is the easiest way to do that.
>>
>> On Fri, Dec 24, 2010 at 10:44 PM, Roshan Dawrani
>> <ro...@gmail.com> wrote:
>>> Hi,
>>>
>>> I am new to Cassandra and Hector and have a basic question on fetching
>>> multiple columns of a row that have mixed data types.
>>>
>>> So, I am basically doing equivalent of "Select dateCol1, dateCol2,
>>> stringCol1, intCol1 from a_table where key in (?, ?, ?...)"
>>>
>>> My question is do I need to do the conversion of columns from byte[] to
>>> Date/String/Int myself after taking out data from the ColumnSlice?
>>>
>>> For saving the same data, while adding the columns, I was able to tell which
>>> serializer to use, but slice queries seem to take only one ValueSerializer
>>> for all columns being retrieved. So, if I have got it correctly, I can only
>>> use ByteBufferSerializer in the Hector API slice query call and then do
>>> further data-type specific conversion myself at the app level?
>>>
>>> --
>>> Roshan
>>> Blog: http://roshandawrani.wordpress.com/
>>> Twitter: @roshandawrani
>>> Skype: roshandawrani
>>>
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>