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From Jean-Marc Spaggiari <jean-m...@spaggiari.org>
Subject Re: table splitting - how to check
Date Wed, 25 Feb 2015 15:14:18 GMT
Hi Marcelo,

Truncate also removes the regions boundaries. You can use truncate_preserve
if you want to keep your region splits. Not sure if it's available in
0.96...

Also, I don't think you can look at the splits from the shell command...

JM

2015-02-25 10:09 GMT-05:00 Marcelo Valle (BLOOMBERG/ LONDON) <
mvallemilita@bloomberg.net>:

> Hi,
>
> I have created an HBase table just like that:
>
> t = create 'HBaseSerialWritesPOC', 'user_id_ts', {NAME => 'alnfo'},
> {SPLITS => ['100000000000000000000000', '200000000000000000000000',
> '300000000000000000000000', '400000000000000000000000',
> '500000000000000000000000', '600000000000000000000000',
> '700000000000000000000000', '800000000000000000000000',
> '900000000000000000000000', 'a00000000000000000000000',
> 'b00000000000000000000000', 'c00000000000000000000000',
> 'd00000000000000000000000', 'e00000000000000000000000',
> 'f00000000000000000000000']}
>
> After some tests, I truncated the table.
>
> Then I inserted 1 million rows, just to test. I was expecting to have 16
> regions for this table, but when I checked admin UI, I saw two regions:
>
> Table Regions
> Name       Region Server   Start Key       End Key Requests
> HBaseSerialWritesPOC,,1424873821297.cf92656f68a16e9696d0fbfe2494219b.
>   host1           800000190000125396f3f2bb        500625
> HBaseSerialWritesPOC,800000190000125396f3f2bb,1424873821297.696a25e590e3248005c638c0f86c0564.
> host2   800000190000125396f3f2bb                500621
>
> I am new to HBase, so it really means just 2 regions have been created,
> right? It seems keys have been split in a half, 0000.. To ffff...
>
> I disabled, dropped and created the table again using the same command
> bellow, then I saw 16 regions, as expected.
>
> Question 1: Is it possible to check the same thing using hbase shell?
>
> Question 2: Is it expected behavior the truncate messing up the splits?
> What kind of DML operations could change the splits in my table? I am using
> HBase 0.96.1.2.0.10.0-1-hadoop2
>
> -Marcelo

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