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HBase >> mail # user >> HBase 0.92.1 - triggering major compaction


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kzurek 2013-01-30, 15:55
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Re: HBase 0.92.1 - triggering major compaction
On Wed, Jan 30, 2013 at 7:55 AM, kzurek <[EMAIL PROTECTED]> wrote:
> Hi,
>
>  I'm having following issues with triggering manually major compaction on
> selected regions via HBaseAdmin:
>  1. When I'm triggering major compaction on first region, which does not
> contains key, it's running normally - I see message in logs ([..]Large
> Compaction requested ... Because: User-triggered major compaction;[...]) and
> after some time it's executed (info in logs). Example region name:
> test,,1359115210217.7315770e499a47e0598849d8702ed202.

What do you mean by "does not contain key"? Are you saying that they
are simply empty or or are you starting major compactions using a row
key?

>  2. When I'm triggering major compaction on some chosen region (this one
> contains a key) I see no information as before, like it would not be
> triggered, although I'm not getting any errors or so. Thus, I'm not sure if
> compaction which will be executed is major or rather minor. Moreover, I've
> noticed that on one region which was previously (2h before) triggered for
> compaction, I've received  only information about the end of compaction
> (Store: Completed major compaction of 3 file(s) in data of [...]). Example
> region name:
> test,\x00|@\x07\x00\x00\x0A\x19,1359529282226.aa16fae842a3e3f38a6ee75dc6a2941a.

Same question regarding "this one contains a key". But if you are
indeed in DEBUG-level then you should see the compaction being
requested. Can you post a log snippet in a pastebin.com (or similar)?

>  3. How can I verify for sure that major compaction was really triggered?
> I've also read on forum that since 0.92 version MC is triggered
> asynchronously (is it?).

IIRC it always was async, the client didn't wait on the compaction to
end before returning. The sure way to verify for sure if by looking at
the log, unfortunately.

>  4. Why there is no such information in logs saying that major compaction
> was triggered or is rolling (logs on DEBUG at the moment)?

I guess there's something else we're missing but it's not like I can
log into your cluster and verify it :) So log snippets are always
useful.

>  5. Where can I find some detailed information about major compaction
> itself?

The best documentation is always the code itself, the book contains
some information regarding compactions in general but I don't think it
goes into the details.

J-D
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kzurek 2013-02-04, 12:02