Re: pglz performance

On Wed, Nov 27, 2019 at 05:01:47PM +0900, Michael Paquier wrote:
>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?

I'd like some feedback from Andrey regarding the results and memmove
comment, ant then I'll polish and push.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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