Re: pglz performance

On Tue, Nov 26, 2019 at 09:05:59PM +0100, Tomas Vondra wrote:
> Yeah, although the difference is minimal. We could probably construct a
> benchmark where #2 wins, but I think these queries are fairly realistic.
> So I'd just go with #1.

Nice results. Using your benchmarks it indeed looks like patch 1 is a
winner here.

> Code-wise I think the patches are mostly fine, although the comments
> might need some proof-reading.
>
> 1) I wasn't really sure what a "nibble" is, but maybe it's just me and
> it's a well-known term.
>
> 2) First byte use lower -> First byte uses lower
>
> 3) nibble contain upper -> nibble contains upper
>
> 4) to preven possible uncertanity -> to prevent possible uncertainty
>
> 5) I think we should briefly explain why memmove would be incompatible
> with pglz, it's not quite clear to me.
>
> 6) I'm pretty sure the comment in the 'while (off < len)' branch will be
> badly mangled by pgindent.
>
> 7) The last change moving "copy" to the next line seems unnecessary.

Patch 1 has a typo as well here:
+ * When offset is smaller than lengh - source and
s/lengh/length/

Okay, if we are reaching a conclusion here, Tomas or Peter, are you
planning to finish brushing the patch and potentially commit it?
--
Michael