Re: Compression of full-page-writes

On Wed, May 28, 2014 at 04:04:13PM +0100, Simon Riggs wrote:
> On 28 May 2014 15:34, Fujii Masao <masao.fujii@gmail.com> wrote:
> 
> >> Also, compress_backup_block GUC needs to be merged with full_page_writes.
> >
> > Basically I agree with you because I don't want to add new GUC very similar to
> > the existing one.
> >
> > But could you imagine the case where full_page_writes = off. Even in this case,
> > FPW is forcibly written only during base backup. Such FPW also should be
> > compressed? Which compression algorithm should be used? If we want to
> > choose the algorithm for such FPW, we would not be able to merge those two
> > GUCs. IMO it's OK to always use the best compression algorithm for such FPW
> > and merge them, though.
> 
> I'd prefer a new name altogether
> 
> torn_page_protection = 'full_page_writes'
> torn_page_protection = 'compressed_full_page_writes'
> torn_page_protection = 'none'
> 
> this allows us to add new techniques later like
> 
> torn_page_protection = 'background_FPWs'
> 
> or
> 
> torn_page_protection = 'double_buffering'
> 
> when/if we add those new techniques

Uh, how would that work if you want to compress the background_FPWs? 
Use compressed_background_FPWs?

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