Hi Pankaj
If your threads are generating data (0..99999, 100000...199999,
200000...299999, ...) of this format, your splits also should be like
0.....10000
10000...20000
20000...30000 and so on right? May be am missing something here.
But the data generation that creates the rowkey and the pre split regions'
start and endkey have the same format right.
Means if the start and endkeys is created using Bytes.toString("xxx") then the
rowkey should also be of that format. If it is Bytes.toInt(xxx) then the
internal byte representation may
Be different.
Regards
Ram
> -----Original Message-----
> From: Pankaj Misra [mailto:[email protected]]
> Sent: Tuesday, September 25, 2012 12:42 PM
> To: [email protected]
> Subject: RE: HBase BatchMutations - HOT Region Problem
>
> Please find attached the table split and the snapshot below.
>
> Start Key End Key
> 199999
> 199999 333332
> 333332 00000000004ccccb
> 00000000004ccccb 666664
> 666664 00000000007ffffd
> 00000000007ffffd 999996
> 999996 0000000000b3332f
> 0000000000b3332f 0000000000ccccc8
> 0000000000ccccc8 0000000000e66661
> 0000000000e66661
>
> As can be seen from the snapshot, the last region being filled up alone
> with all the data, containing the keys which do not belong the that
> range as well.
>
> One doubt that I do have however is the way the keys are being
> generated the client side. The keys are generated incrementally per
> thread and add to the offset. This is then converted to its string
> representation and written as ByteBuffer. So converting an integer key
> to its String form and then writing it as a ByteBuffer could be a
> problem?
>
>
> Thanks and Regards
> Pankaj Misra
>
>
> ________________________________________
> From: Anoop Sam John [[email protected]]
> Sent: Tuesday, September 25, 2012 12:18 PM
> To: [email protected]
> Subject: RE: HBase BatchMutations - HOT Region Problem
>
> Your table is presplit. Can you give the splitkeys that you have used?
>
> -Anoop-
> ________________________________________
> From: Pankaj Misra [[email protected]]
> Sent: Tuesday, September 25, 2012 11:45 AM
> To: [email protected]
> Subject: HBase BatchMutations - HOT Region Problem
>
> Dear All,
>
> I am using HBASE 0.94.1 with Hadoop 0.23.1. I have written a multi-
> threaded thrift client to load the data into HBASE using
> BatchMutations. The size of each batch is 1000 rows and the table in
> HBASE is split into 10 regions. The rows are increasing
> incrementally(0...999999) with offsets applied for each of the
> threads(0..99999, 100000...199999, 200000...299999, ...), so in theory
> every thread is expected to write in different region. The individual
> regions are wide, i.e. every region is expected to store about 100000
> rows, so this makes it a total of 1000000 rows across all the regions.
>
> I am using thrift server/client and only 1 region server as per the
> default HBase setup.
>
> So if I spawn 10 threads with offsets applied accordingly I was
> expecting the regions to be getting parallely filled up which does not
> seem to be the case. All the inserts pile into the the same region
> which make the writes inefficient due to frequent compacting cycles
> blocking all the threads. If the threads would have been writing to
> different regions, this problem could have been much smaller.
>
> I am not sure if I am missing out on anything, any ideas would be very
> helpful.
>
> Thanks and Regards
> Pankaj Misra
>
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> Impetus Ranked in the Top 50 India’s Best Companies to Work For 2012.
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> Impetus webcast ‘Designing a Test Automation Framework for Multi-vendor
> Interoperable Systems’ available at http://lf1.me/0E/.
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