Re: pluggable compression support

On Saturday, June 15, 2013 3:50 PM Andres Freund wrote:
On 2013-06-14 21:56:52 -0400, Robert Haas wrote:
>> I don't think we need it. I think what we need is to decide is which
>> algorithm is legally OK to use. And then put it in.
>>
>> In the past, we've had a great deal of speculation about that legal
>> question from people who are not lawyers. Maybe it would be valuable
>> to get some opinions from people who ARE lawyers. Tom and Heikki both
>> work for real big companies which, I'm guessing, have substantial
>> legal departments; perhaps they could pursue getting the algorithms of
>> possible interest vetted. Or, I could try to find out whether it's
>> possible do something similar through EnterpriseDB.

> I personally don't think the legal arguments holds all that much water
> for snappy and lz4. But then the opinion of a european non-lawyer doesn't
> hold much either.
> Both are widely used by a large number open and closed projects, some of
> which have patent grant clauses in their licenses. E.g. hadoop,
> cassandra use lz4, and I'd be surprised if the companies behind those
> have opened themselves to litigation.

> I think we should preliminarily decide which algorithm to use before we
> get lawyers involved. I'd surprised if they can make such a analysis
> faster than we can rule out one of them via benchmarks.

I have also tried to use snappy for patch "Performance Improvement by reducing WAL for Update Operation".
It has shown very good results and performed very well for all the tests asked by Heikki.
Results are at below link:
http://www.postgresql.org/message-id/009001ce2c6e$9bea4790$d3bed6b0$@kapila@huawei.com

I think if we can get snappy into core, it can be used for more things.
I wanted to try it for FPW as well.

With Regards,
Amit Kapila.