Varun Sharma 2012-12-10, 13:58
lars hofhansl 2012-12-11, 05:06
Varun Sharma 2012-12-11, 05:09
ramkrishna vasudevan 2012-12-10, 14:08
Varun Sharma 2012-12-10, 14:59
Varun Sharma 2012-12-10, 15:29
-Re: Filtering/Collection columns during Major Compaction
lars hofhansl 2012-12-11, 05:09
In your case you probably just want to filter on top of the provided scanner with preCompact (rather than actually replacing the scanner, which preCompactScannerOpen does).
(And sorry I only saw this reply after I sent my own reply to your initial question.)
From: Varun Sharma <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Sent: Monday, December 10, 2012 7:29 AM
Subject: Re: Filtering/Collection columns during Major Compaction
Okay - I looked more thoroughly again - I should be able to extract these
from the region observer.
On Mon, Dec 10, 2012 at 6:59 AM, Varun Sharma <[EMAIL PROTECTED]> wrote:
> Thanks ! This is exactly what I need. I am looking at the code in
> compactStore() under Store.java but I am trying to understand why, for the
> real compaction - smallestReadPoint needs to be passed - I thought the read
> point was a memstore only thing. Also the preCompactScannerOpen does not
> have a way of passing this value.
> On Mon, Dec 10, 2012 at 6:08 AM, ramkrishna vasudevan <
> [EMAIL PROTECTED]> wrote:
>> Hi Varun
>> If you are using 0.94 version you have a coprocessor that is getting
>> invoked before and after Compaction selection.
>> preCompactScannerOpen() helps you to create your own scanner which
>> does the next() operation.
>> Now if you can wrap your own scanner and implement your next() it will
>> you to play with the kvs that you need. So basically you can say what
>> to include and what to exclude.
>> Does this help you Varun?
>> On Mon, Dec 10, 2012 at 7:28 PM, Varun Sharma <[EMAIL PROTECTED]>
>> > Hi,
>> > My understanding of major compaction is that it rewrites one store file
>> > does a merge of the memstore, store files on disk and cleans out delete
>> > tombstones and puts prior to them and cleans out excess versions. We
>> > to limit the number of columns per row in hbase. Also, we want to limit
>> > them in lexicographically sorted order - which means we take the top,
>> > 100 smallest columns (in lexicographical sense) and only keep them while
>> > discard the rest.
>> > One way to do this would be to clean out columns in a daily mapreduce
>> > Or another way is to clean them out during the major compaction which
>> > be run daily too. I see, from the code that a major compaction
>> > invokes a Scan over the region - so if the Scan is invoked with the
>> > appropriate filter (say ColumnCountGetFilter) - would that do the trick
>> > Thanks
>> > Varun
Varun Sharma 2012-12-11, 07:04
lars hofhansl 2012-12-11, 07:19
Varun Sharma 2012-12-12, 00:51
lars hofhansl 2012-12-12, 01:58
Anoop Sam John 2012-12-11, 04:10