On 3/9/2012 9:47 AM, Merlin Moncure wrote:
> On Thu, Mar 8, 2012 at 2:01 PM, Andy Colson<andy@squeakycode.net> wrote:
>> I know toast compresses, but I believe its only one row. page level would
>> compress better because there is more data, and it would also decrease the
>> amount of IO, so it might speed up disk access.
>
> er, but when data is toasted it's spanning pages. page level
> compression is a super complicated problem.
>
> something that is maybe more attainable on the compression side of
> things is a userland api for compression -- like pgcrypto is for
> encryption. even if it didn't make it into core, it could live on
> reasonably as a pgfoundry project.
>
> merlin
Agreed its probably too difficult for a GSoC project. But userland api
would still be row level, which, in my opinion is useless. Consider
rows from my apache log that I'm dumping to database:
date, url, status
2012-3-9 10:15:00, '/index.php?id=4', 202
2012-3-9 10:15:01, '/index.php?id=5', 202
2012-3-9 10:15:02, '/index.php?id=6', 202
That wont compress at all on a row level. But it'll compress 99% on a
"larger" (page/multirow/whatever/?) level.
-Andy
