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From Stack <st...@duboce.net>
Subject Re: HBase as a versioned key/value store
Date Wed, 03 Nov 2010 15:32:55 GMT
On Wed, Nov 3, 2010 at 7:15 AM, Wojciech Langiewicz
<wlangiewicz@gmail.com> wrote:
> I'm running latest version from Cloudera

Try a later version of the 0.89 series.  See the downloads page on our
site.   It has perf. improvements.

>> Each KV is a distinct Put operation?  Normally people get high throughput
>> by batching many Puts at once.
> Actually, here I'm asking about Get operations, because I don't know how to
> batch them (by design). But in case of Puts you are right.

There is a batch Get in TRUNK that should be available as 0.90.0RC0 soon.

> I'm rather asking what can I expect from my schema design and hardware by
> comparing other people solutions, right now I'm getting 10 times less
> performance that I initially wanted.
Well, if going to disk, reading we're talking 10-30ms a hit.  If you
are reading from cache, you should see 5ms and less.  Try upping
proportion of your heap given over to block cache; set
hfile.block.cache.size to 0.4 or 0.5 of heap (Writes should be going
in pretty fast -- ~5m or less).

What size your cells?  How many regions in your table?   How much RAM
have you given over to HBase?   Anything else running on these
machines?  You doing any wacky RAID'ing on those disks?

Good luck,

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