Thank you ted. I might have to rethink my key design to accomodate
this. With this design and using the totals in keys as you suggested, I
would have to scan the entire "California" group to find the totals.
Thank you very much for your help.
-John
On Wed 09 Oct 2013 08:43:12 PM PDT, Ted Yu wrote:
John:
Suppose 'California-**12346' is the start key of region 1 and 'California-**
95424' is the start key of region 2. You can choose 'California-**12346#total'
to be the row key where increment is done for region 1 and
'California-**95424#total'
to be the row key where increment is done for region 2.
w.r.t. verification of whether given row key is indeed inside the hosting
region, see the following:
void checkRow(final byte [] row, String op) throws IOException {
if (!rowIsInRange(getRegionInfo(), row)) {
throw new WrongRegionException("Requested row out of range for " +
op + " on HRegion " + this + ", startKey='" +
Cheers
On Wed, Oct 9, 2013 at 8:26 PM, John Weatherford <
[email protected]> wrote:
First, Thank you everyone for the quick response.
Ted:
The custom split policy could be an interesting solution. Regarding the
other option you sent, if I pull the end row key, I could construct an end
key, but if I suffix the row key with the end key of the region, would that
actually solve my problem? In the contrived case, wouldn't the suffixed key
now be "California-total-California-**12346" and the other region's
counter would be "California-total-California-**95424" and both of these
keys would actually end up on the second region since the sorting of the
keys would impose that "California-t*" comes after "California-[1-9]".
Part of the question is that I don't understand if calling
incrementColumnValue() on the region will always execute on the region
called, regardles of rowkey. If so, what happens when those regions are
merged?
Thanks again for the help!
On Wed 09 Oct 2013 07:43:34 PM PDT, Ted Yu wrote:
bq. 'California-total' row in each region
Of course such row key needs to be suffixed with either start or end key
of
the corresponding region.
On Wed, Oct 9, 2013 at 7:39 PM, Ted Yu <[email protected]> wrote:
John:
Looks like you need a 'California-total' row in each region.
Custom Split Policy can help you achieve that, see 9.7.4.1 in:
http://hbase.apache.org/book.**html#d0e6541<http://hbase.apache.org/book.html#d0e6541>
Cheers
On Wed, Oct 9, 2013 at 7:28 PM, Vladimir Rodionov <
[email protected]
wrote:
Contrived Example
Insert rowkey "California-12345" triggers a coprocessor to call
incrementColumnValue() with a rowkey of "California-total" all on
Region 1.
This would likely be on an insert on the same region. But as the table
grows, this secondary insert could end up on another region. If it is
confined, then suppose we later insert "California-95424" which still
triggers a call to incrementColumnValue() with a rowkey of
"California-total" all on Region 2.
Are we now left with two rowkeys of "California-total"? One on each
region server? If so, what happens if these two regions are compacted
into one?
Best regards,
Nope, Your "California-total" will migrate to Region 2 after region
split
is complete.
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: [email protected]
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