hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Rendon, Carlos (KBB)" <CRen...@kbb.com>
Subject RE: Help with row and column design
Date Wed, 30 Apr 2014 16:21:17 GMT
> Ok didnt know if the sheer number of gets would be a limiting factor. Thanks

Yes retrieving and summing thousands of rows is much slower and requires more network, memory,
cpu, than doing that for a hundred or <10.
Perhaps day-level, week-level, or month-level granularity would be a better fit for a 6 month
aggregation? 
You did say you were going to store data at multiple levels of time aggregation right?


-----Original Message-----
From: Software Dev [mailto:static.void.dev@gmail.com] 
Sent: Tuesday, April 29, 2014 8:05 PM
To: user@hbase.apache.org
Subject: Re: Help with row and column design

Ok didnt know if the sheer number of gets would be a limiting factor. Thanks

On Tue, Apr 29, 2014 at 7:57 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> As I said this afternoon:
> See the following API in HTable for batching Get's :
>
>   public Result[] get(List<Get> gets) throws IOException {
>
> Cheers
>
>
> On Tue, Apr 29, 2014 at 7:45 PM, Software Dev <static.void.dev@gmail.com>wrote:
>
>> Nothing against your code. I just meant that if we are doing a scan 
>> say for hourly metrics across a 6 month period we are talking about
>> 4K+ gets. Is that something that can easily be handled?
>>
>> On Tue, Apr 29, 2014 at 5:08 PM, Rendon, Carlos (KBB) 
>> <CRendon@kbb.com>
>> wrote:
>> >> Gets a bit hairy when doing say a shitload of gets thought.. no?
>> >
>> > If you by "hairy" you mean the code is ugly, it was written for 
>> > maximal
>> clarity.
>> > I think you'll find a few sensible loops makes it fairly clean.
>> > Otherwise I'm not sure what you mean.
>> >
>> > -----Original Message-----
>> > From: Software Dev [mailto:static.void.dev@gmail.com]
>> > Sent: Tuesday, April 29, 2014 5:02 PM
>> > To: user@hbase.apache.org
>> > Subject: Re: Help with row and column design
>> >
>> >> Yes. See total_usa vs. total_female_usa above. Basically you have 
>> >> to
>> pre-store every level of aggregation you care about.
>> >
>> > Ok I think this makes sense. Gets a bit hairy when doing say a 
>> > shitload
>> of gets thought.. no?
>> >
>> > On Tue, Apr 29, 2014 at 4:43 PM, Rendon, Carlos (KBB) 
>> > <CRendon@kbb.com>
>> wrote:
>> >> You don't do a scan, you do a series of gets, which I believe you 
>> >> can
>> batch into one call.
>> >>
>> >> last 5 days query in pseudocode
>> >> res1 = Get( hash("2014-04-29") + "2014-04-29")
>> >> res2 = Get( hash("2014-04-28") + "2014-04-28")
>> >> res3 = Get( hash("2014-04-27") + "2014-04-27")
>> >> res4 = Get( hash("2014-04-26") + "2014-04-26")
>> >> res5 = Get( hash("2014-04-25") + "2014-04-25")
>> >>
>> >> For each result you look for the particular column or columns you 
>> >> are interested in Total_usa = res1.get("c:usa") + 
>> >> res2.get("c:usa") +
>> res3.get("c:usa") + ...
>> >> Total_female_usa = res1.get("c:usa:sex:f") + ...
>> >>
>> >> "What happens when we add more fields? Do we just keep adding in 
>> >> more
>> column qualifiers? If so, how would we filter across columns to get 
>> an aggregate total?"
>> >>
>> >> Yes. See total_usa vs. total_female_usa above. Basically you have 
>> >> to
>> pre-store every level of aggregation you care about.
>> >>
>> >> -----Original Message-----
>> >> From: Software Dev [mailto:static.void.dev@gmail.com]
>> >> Sent: Tuesday, April 29, 2014 4:36 PM
>> >> To: user@hbase.apache.org
>> >> Subject: Re: Help with row and column design
>> >>
>> >>> The downside is it still has a hotspot when inserting, but when 
>> >>> reading a range of time it does not
>> >>
>> >> How can you do a scan query between dates when you hash the date?
>> >>
>> >>> Column qualifiers are just the collection of items you are 
>> >>> aggregating on. Values are increments. In your case qualifiers 
>> >>> might look like c:usa, c:usa:sex:m, c:usa:sex:f, c:italy:sex:m, 
>> >>> c:italy:sex:f, c:italy,
>> >>
>> >> What happens when we add more fields? Do we just keep adding in 
>> >> more
>> column qualifiers? If so, how would we filter across columns to get 
>> an aggregate total?
>>
Mime
View raw message