Re: Performance Improvement by reducing WAL for Update Operation

On Tuesday, January 29, 2013 3:53 PM Heikki Linnakangas wrote:
> On 29.01.2013 11:58, Amit Kapila wrote:
> > Can there be another way with which current patch code can be made
> better,
> > so that we don't need to change the encoding approach, as I am having
> > feeling that this might not be performance wise equally good.
> 
> The point is that I don't want to heap_delta_encode() to know the
> internals of pglz compression. You could probably make my patch more
> like yours in behavior by also passing an array of offsets in the new
> tuple to check, and only checking for matches as those offsets.

I think it makes sense, because if we have offsets of both new and old
tuple, we
can internally use memcmp to compare columns and use same algorithm for
encoding.
I will change the patch according to this suggestion.

With Regards,
Amit Kapila.