Re: PostgreSQL vs SQL/XML Standards

From: Chapman Flack <chap(at)anastigmatix(dot)net>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: PostgreSQL vs SQL/XML Standards
Date: 2019-01-25 04:46:29
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On 01/21/19 01:33, Pavel Stehule wrote:
> ne 20. 1. 2019 23:13 odesílatel Chapman Flack <chap(at)anastigmatix(dot)net>
> napsal:

>> form (whether or not the word LATERAL is used), and re-executes xmltable
>> whenever the referenced column value changes. In that case, whether the
>> default argument is evaluated at function entry or later doesn't seem
>> to matter: the function is re-executed, so evaluating the new default
>> at the time of entry is sufficient.
> it has sense only for volatile functions. it was not often. On second hand
> deferred evaluation shoul not be a problem, and more, it is evaluated only
> when it is necessary, what is more sensible for me.

That makes sense. I trimmed the language about input rows and referring to
earlier columns, and put more emphasis on the usefulness of evaluating
volatile functions only when needed.

I am:

- re-attaching xmltable-xpath-result-processing-bugfix-5.patch unchanged
(just so CF app does not lose track)

- re-attaching xmltable-xmlexists-passing-mechanisms-1.patch unchanged

- attaching for the first time xml-functions-type-docfix-1.patch

The doc patch is made to go on top of the passing-mechanisms patch
(there were some doc changes in passing-mechanisms, changed again in
the new patch to be links to the added Limits and Compatibility section).

I hope the patched docs describe accurately what we have at this point.


Attachment Content-Type Size
xmltable-xpath-result-processing-bugfix-5.patch text/x-patch 14.2 KB
xmltable-xmlexists-passing-mechanisms-1.patch text/x-patch 5.8 KB
xml-functions-type-docfix-1.patch text/x-patch 30.1 KB

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