Re: [REVIEW] Re: Fix xpath() to return namespace definitions

2014-12-15 11:02 GMT+07:00 Ali Akbar <the(dot)apaan(at)gmail(dot)com>:
>
> 2014-12-15 10:19 GMT+07:00 Michael Paquier <michael(dot)paquier(at)gmail(dot)com>:
>>
>> On Mon, Dec 15, 2014 at 9:05 AM, Ali Akbar <the(dot)apaan(at)gmail(dot)com> wrote:
>> > Peter, while reviewing the better performing patch myself, now i think
>> the
>> > patch needs more work to be committed. The structuring of the method
>> will be
>> > confusing in the long term. I think I'll restructure the patch in the
>> next
>> > commitfest.
>> > So i propose to break the patch:
>> > 1. We apply the current patch which uses xmlNodeCopy, so that the
>> > long-standing bug will be fixed in postgres.
>> > 2. I'll work with the performance enhancement in the next commitfest.
>> >
>> > Maybe for (2), the current better-performing patch can be viewed as PoC
>> of
>> > the expected performance.
>>
>> Ali, are you currently working on that? Would you mind re-creating new
>> entries in the commit fest app for the new set of patches that you are
>> planning to do?
>> For now I am switching this patch as returned with feedback.
>> Thanks,
>>
>
> What i mean, the last patch (v7 patch) as it is is enough to fix the bug
> (nested xpath namespace problem). I think the performance regression is
> still acceptable (in my case it's ~20%), because the bug is severe.
> Currently, xpath can return invalid xml because the namespace isn't
> included in the output!
>

Sorry, typo here. What i mean isn't "invalid xml", but "incomplete xml".
Hence the next call to xpath with the previous result as its input will
become a problem because the namespace will not match.

>
> What i'll be working is the v4 patch, because it turns out the v4 patch
> has better performance (~10%, but Peter's test shows it isn't the case).
> But, the problem is the v4 patch is organized wrongly, and hacks around the
> libxml's xml node structure (duplicating the namespace on the existing
> structure). I'll work on that, but it will affects the performance benefit.
>
> So what i propose is, we close the longstanding bug in this comitfest with
> the v7 patch. I'll work on improving the performance, without compromising
> good code structure. If the result is good, i'll submit the patch.
>
> Thanks
>

Regards,
--
Ali Akbar