Re: Quick-and-dirty compression for WAL backup blocks

Heikki Linnakangas <hlinnaka@iki.fi> writes:
> On Mon, 6 Jun 2005, Tom Lane wrote:
>> Heikki Linnakangas <hlinnaka@iki.fi> writes:
>>> Vacuum doesn't zero out the free space between lower and upper,
>> 
>> It does now ;-)

> Oh :). Does it affect vacuum performance?

I haven't tried to measure it ... but certainly it's not totally free.
I'd be happy to rip that change out again.

>> Would this be institutionalizing a particular approach to data
>> compression in the XLogInsert API, though?

> The "skip the free space" optimization is still useful and worthwhile 
> even if we have a more sophisticated compression method for the 
> rest of the page.

Good point.  OK, I'm hacking XLOG stuff now anyway so I'll see about
making that happen.
        regards, tom lane