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HBase >> mail # user >> Is it possible to indicate the column scan order when scanning table?


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Re: Is it possible to indicate the column scan order when scanning table?
Thanks for your response. I will take a look.

yong
On Thu, Feb 7, 2013 at 10:11 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
> Yonghu:
> You may want to take a look at HBASE-5416: Improve performance of scans
> with some kind of filters.
> It would be in the upcoming 0.94.5 release.
>
> You can designate an essential column family. Based on the result from this
> column family, extra column family can be scanned.
>
> Cheers
>
> On Thu, Feb 7, 2013 at 1:07 PM, Sergey Shelukhin <[EMAIL PROTECTED]>wrote:
>
>> CFs are scanned in parallel in HBASE, and each row is built; scanning
>> entire CF and then building rows by scanning entire different CF wouldn't
>> scale very well.
>> Do you filter data on ttl column family?
>>
>> On Thu, Feb 7, 2013 at 12:01 PM, yonghu <[EMAIL PROTECTED]> wrote:
>>
>> > Like a table can contain ttl data and static data without indicating
>> > ttl. So, I want to first scan the columns which have ttl restrictions
>> > and later the static columns. The goal that I want to achieve is to
>> > reduce the data missing due to ttl expiration during the scan.
>> >
>> > regards!
>> >
>> > Yong
>> >
>> > On Thu, Feb 7, 2013 at 6:29 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>> > > Can you give us the use case where the scanning order is significant ?
>> > >
>> > > Thanks
>> > >
>> > > On Thu, Feb 7, 2013 at 9:23 AM, yonghu <[EMAIL PROTECTED]> wrote:
>> > >
>> > >> Dear all,
>> > >>
>> > >> I wonder if it is possible to indicate the column scan order when
>> > >> scanning table. For example, if I have two column families cf1 and cf2
>> > >> and I create a scan object. Is the table scanning order of
>> > >> scan.addFamily(cf1) and   scan.addFamily(cf2) is as same as
>> > >> scan.addFamily(cf2) and scan.addFamily(cf1)? If it's the same order,
>> > >> is it possible to indicate the scanning order of table?
>> > >>
>> > >> regards!
>> > >>
>> > >> Yong
>> > >>
>> >
>>