Re: Proposal: Incremental Backup

On Tue, Aug 5, 2014 at 9:17 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> On Wed, Aug 6, 2014 at 9:04 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>>
>> On 5 August 2014 22:38, Claudio Freire <klaussfreire@gmail.com> wrote:
>> Thinking some more, there seems like this whole store-multiple-LSNs
>> thing is too much. We can still do block-level incrementals just by
>> using a single LSN as the reference point. We'd still need a complex
>> file format and a complex file reconstruction program, so I think that
>> is still "next release". We can call that INCREMENTAL BLOCK LEVEL.
>
> Yes, that's the approach taken by pg_rman for its block-level
> incremental backup. Btw, I don't think that the CPU cost to scan all
> the relation files added to the one to rebuild the backups is worth
> doing it on large instances. File-level backup would cover most of the
> use cases that people face, and simplify footprint on core code. With
> a single LSN as reference position of course to determine if a file
> needs to be backup up of course, if it has at least one block that has
> been modified with a LSN newer than the reference point.


It's the finding of that block that begs optimizing IMO.