As per the above said, you will need a full table scan on that CF. As Ted said, consider having a look at your schema design.
-Anoop- On Sun, Mar 10, 2013 at 8:10 PM, Ted Yu <[email protected]> wrote: > bq. physically column family should be able to perform efficiently (storage > layer > > When you scan a row, data for different column families would be brought > into memory (if you don't utilize HBASE-5416) > Take a look at: > > https://issues.apache.org/jira/browse/HBASE-5416?focusedCommentId=13541258&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13541258 > > which was based on the settings described in: > > > https://issues.apache.org/jira/browse/HBASE-5416?focusedCommentId=13541191&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13541191 > > This boils down to your schema design. If possible, consider extracting > column C into its own column family. > > Cheers > > On Sun, Mar 10, 2013 at 7:14 AM, PG <[email protected]> wrote: > > > Hi, Ted and Anoop, thanks for your notes. > > I am talking about column rather than column family, since physically > > column family should be able to perform efficiently (storage layer, CF's > > are stored separately). But columns of the same column family may be > mixed > > physically, and that makes filters column value hard... So I want to know > > if there are any mechanism in HBase worked on this... > > Regards, > > Yun > > > > On Mar 10, 2013, at 10:01 AM, Ted Yu <[email protected]> wrote: > > > > > Hi, Yun: > > > Take a look at HBASE-5416 (Improve performance of scans with some kind > of > > > filters) which is in 0.94.5 release. > > > > > > In your case, you can use a filter which specifies column C as the > > > essential family. > > > Here I interpret column C as column family. > > > > > > Cheers > > > > > > On Sat, Mar 9, 2013 at 11:11 AM, yun peng <[email protected]> > wrote: > > > > > >> Hi, All, > > >> I want to find all existing values for a given column in a HBase, and > > would > > >> that result in a full-table scan in HBase? For example, given a column > > C, > > >> the table is of very large number of rows, from which few rows (say > > only 1 > > >> row) have non-empty values for column C. Would HBase still ues a full > > table > > >> scan to find this row? Or HBase has any optimization work for this > kind > > of > > >> query? > > >> Thanks... > > >> Regards > > >> Yun > > >> > > >
