Re: Improve compression speeds in pg_lzcompress.c

On 7 January 2013 09:19, John R Pierce <pierce@hogranch.com> wrote:
> On 1/7/2013 1:10 AM, Simon Riggs wrote:
>>
>> On 7 January 2013 07:29, Takeshi Yamamuro
>> <yamamuro.takeshi@lab.ntt.co.jp>  wrote:
>>
>>> >Anyway, the compression speed in lz4 is very fast, so in my
>>> >opinion, there is a room to improve the current implementation
>>> >in pg_lzcompress.
>>
>> So why don't we use LZ4?
>
> what will changing compression formats do for compatability?
>
> this is for the compressed data in pg_toast storage or something? will this
> break pg_upgrade style operations?

Anything that changes on-disk format would need to consider how to do
pg_upgrade. It's the major blocker in that area.

For this, it would be possible to have a new format and old format
coexist, but that will take more time to think through than we have
for this release, so this is a nice idea for further investigation in
9.4. Thanks for raising that point.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services