What would columnar organization look like and what are the benefits
and drawbacks to this?
Josh
On Dec 14, 2008, at 3:13 PM, Joydeep Sen Sarma wrote:
That’s a hard one. We can wish whatever we want to – but I guess
it’s all a question of who has the resources to contribute to it and
what they want from Hive.
I can speak a little bit about Facebook. The reason we invested in
indexing was not that it was the primary usage (or even a bottleneck
for, say, performance optimization) – but because once you have so
much data in one place – chances are that someone will come along
and want to have quick lookups over some part of it (and u don’t
want to kill ur cluster by doing scans all the time). So that
definitely makes indexing useful. We are also seeing that with
dimensional analysis – where there is a need to drill down into
detailed data – multidimensional indexes can be very useful. So in
the long term – I think this is one of the desired features.
That doesn’t make it akin to hbase though (in the sense that we
still wouldn’t have row level updates or real-time index updates).
Katta may be complimentary and we were actually interested in
investigating it for indexing (instead of rolling things from
scratch).
Columnar organization is also very interesting. With all the hooks
in hadoop (inputformatters) and hive(serdes) – I think it’s fairly
tractable to do this ..
From: Josh Ferguson [mailto:[email protected]]
Sent: Sunday, December 14, 2008 1:20 PM
To: [email protected]
Subject: Re: OLAP with Hive
I'd honestly like to see hive remain a partitioned flat file store.
I don't think indexing what's inside the files is too incredibly
useful in most situations where you'd use hive. I also think this
kind of store is just the right fit for the hadoop and large scale
analytics situation. I don't want to see hive go toward hbase or
katta. What is the long term vision for hive?
Josh
On Dec 14, 2008, at 1:06 PM, Joydeep Sen Sarma wrote:
We have done some preliminary work with indexing – but that’s not
the focus right now and no code is available in the open source
trunk for this purpose. I think it’s fair to say that hive is not
optimized for online processing right now. (and we are quite some
ways off from columnar storage).
From: Martin Matula [mailto:[email protected]]
Sent: Sunday, December 14, 2008 6:54 AM
To: [email protected]
Subject: OLAP with Hive
Hi,
Is Hive capable of indexing the data and storing them in a way
optimized for querying (like a columnar database - bitmap indexes,
compression, etc.)?
I need to be able to get decent response times for queries (up to a
few seconds) over huge amounts of analytical data. Is that
achievable (with appropriate number of machines in a cluster)? I saw
the serialization/deserialization of tables is pluggable. Is that
the way to make the storage more efficient? Any existing
implementation (either ready or in progress) that would be targeted
at this? Or any hints on what I may want to take a look at among the
things that are currently available in Hive/Hadoop?
Thanks,
Martin
