Hotspotting questions

[Mark <st...@gmail.com>]

Right now we have 5 region servers and one of our tables is quite small 
(500k records) therefore it sits all in one region. This is happening 
because we are using a row key that corresponds to a FK in one of our 
MySQL databases so it's sequential in nature. I know the obvious fix for 
this would be to apply some sort of hash function on the rowkey before 
reading/writing but before I go down that route I wanted to know if I 
should bother. When does hot spotting start to become an issue? Would 
you say this is a cause for concern at this time? I should mentioned 
that at this time we are only writing to this table but we will soon be 
going live so it will start receiving get requests.

Thanks for any suggestions.

Re: Hotspotting questions

[Sam Seigal <se...@yahoo.com>]

The question really is if your region server hosting the hot tail end
of the region during sequential *writes* can take the load or not. If
you find in the future that it cannot, manually splitting the regions
is not going to fix the problem IMHO, since the tail end is always the
one that is going to be hot in the case of sequential writes. At that
point you will have to go with another strategy, like prefixing
hashes.

On Sat, Nov 19, 2011 at 8:58 AM, Mark <st...@gmail.com> wrote:
> Also my reads will be far greater than writes so in this case is it fine
> since I can manually split the region if there is a problem with reading?
>
> On 11/19/11 8:09 AM, Mark wrote:
>>
>> Right now we have 5 region servers and one of our tables is quite small
>> (500k records) therefore it sits all in one region. This is happening
>> because we are using a row key that corresponds to a FK in one of our MySQL
>> databases so it's sequential in nature. I know the obvious fix for this
>> would be to apply some sort of hash function on the rowkey before
>> reading/writing but before I go down that route I wanted to know if I should
>> bother. When does hot spotting start to become an issue? Would you say this
>> is a cause for concern at this time? I should mentioned that at this time we
>> are only writing to this table but we will soon be going live so it will
>> start receiving get requests.
>>
>> Thanks for any suggestions.
>

Re: Hotspotting questions

[Mark <st...@gmail.com>]

Also my reads will be far greater than writes so in this case is it fine 
since I can manually split the region if there is a problem with reading?

On 11/19/11 8:09 AM, Mark wrote:
> Right now we have 5 region servers and one of our tables is quite 
> small (500k records) therefore it sits all in one region. This is 
> happening because we are using a row key that corresponds to a FK in 
> one of our MySQL databases so it's sequential in nature. I know the 
> obvious fix for this would be to apply some sort of hash function on 
> the rowkey before reading/writing but before I go down that route I 
> wanted to know if I should bother. When does hot spotting start to 
> become an issue? Would you say this is a cause for concern at this 
> time? I should mentioned that at this time we are only writing to this 
> table but we will soon be going live so it will start receiving get 
> requests.
>
> Thanks for any suggestions.