Re: PoC/WIP: Extended statistics on expressions

On 9/1/21 9:38 PM, Justin Pryzby wrote:
> On Wed, Sep 01, 2021 at 06:45:29PM +0200, Tomas Vondra wrote:
>>>> Patch 0001 fixes the "double parens" issue discussed elsewhere in this
>>>> thread, and patch 0002 tweaks CREATE STATISTICS to treat "(a)" as a simple
>>>> column reference.
>>>
>>> 0002 refuses to create expressional stats on a simple column reference like
>>> (a), which I think is helps to avoid a user accidentally creating useless ext
>>> stats objects (which are redundant with the table's column stats).
>>>
>>> 0002 does not attempt to refuse cases like (a+0), which I think is fine:
>>> we don't try to reject useless cases if someone insists on it.
>>> See 240971675, 701fd0bbc.
>>>
>>> So I am +1 to apply both patches.
>>>
>>> I added this as an Opened Item for increased visibility.
>>
>> I've pushed both fixes, so the open item should be resolved.
>
> Thank you - I marked it as such.
>
> There are some typos in 537ca68db (refenrece)
> I'll add them to my typos branch if you don't want to patch them right now or
> wait to see if someone notices anything else.
>

Yeah, probably better to wait a bit. Any opinions on rejecting
expressions referencing system attributes or no attributes at all?

regards

--
Tomas Vondra
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