Обсуждение: Unsupported version mentioned at Using EXPLAIN

Hi

When referring Doc, found one place mentioned "using 9.3 development sources." at [1]. Which I think 9.3 means PG9.3

[1]
https://www.postgresql.org/docs/current/using-explain.html

It seems to show up since PG9.2 and changed to 9.3 at PG9.3. However, since 9.3 nobody updates the version anymore.
Maybe we can just remove the specific PG version. Say "using current development sources." Thoughts?

Regards,
Tang

On 2021-May-07, tanghy.fnst@fujitsu.com wrote:

> Hi
> 
> When referring Doc, found one place mentioned "using 9.3 development sources." at [1]. Which I think 9.3 means PG9.3
> 
> [1]
> https://www.postgresql.org/docs/current/using-explain.html
> 
> It seems to show up since PG9.2 and changed to 9.3 at PG9.3. However, since 9.3 nobody updates the version anymore. 
> Maybe we can just remove the specific PG version. Say "using current development sources." Thoughts?

I think there's more to this than just changing or removing the version
number; a better approach might be to update the documentation so that
it matches what current versions do.  There are minor changes here and
there and it'd be sad to let it all drift too much from current reality.
The estimated cost for the very first EXPLAIN is different in current
sources from what the docs say, for example; there's also one example
that the docs show to produce an incremental sort, but didn't in my
hands; and there's one additional line in the first EXPLAIN ANALYZE
output (BitmapHeapScans now show number of heap blocks processed).  I
didn't try to run everything but I suggest we need a little bit of effort.

If we just removed the version number, we'd falsify the examples.  I
think we should update both in unison.  Make it say "Using 14
development sources ..." and make sure to use the output from the
current version, then recheck again in a few years.  It is good to keep
these updated as new plan types are added so that everything is covered.

-- 
Álvaro Herrera       Valdivia, Chile

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> On 2021-May-07, tanghy.fnst@fujitsu.com wrote:
>> Maybe we can just remove the specific PG version. Say "using current development sources." Thoughts?

> I think there's more to this than just changing or removing the version
> number; a better approach might be to update the documentation so that
> it matches what current versions do.

Yeah.  The reason why a specific version is mentioned is exactly that
the details tend to change.  I don't know if anyone else has touched
that text, but when I've done so it's been exactly the sort of effort
you mention: run through all the examples in that file and make them
match current reality.  I don't think just taking out the version
number is a good idea.

            regards, tom lane

Tom Lane <tgl@sss.pgh.pa.us> wrote:
> On 2021-May-07, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>> I think there's more to this than just changing or removing the version
>> number; a better approach might be to update the documentation so that
>> it matches what current versions do.

>Yeah.  The reason why a specific version is mentioned is exactly that
>the details tend to change.

Thanks for your kindly explanation on the usage of version number in Doc.
In fact, I noticed the different context in the examples among different PG version like "increment sort" which was
newlyintroduced in PG13.  
The fix I mentioned at the previous mail(change "using 9.3 development sources" to " using current development
sources")is meant to tell users to refer to the "current" PG source. E.G. when a user looks at PG13.2's doc, "current"
=PG13.2. 
Since I do think your advice on the fix is more reasonable and friendly, I followed your hint to modify the Doc in the
attachedpatch. 
Please tell me if there's anything else insufficient.

Regards,
Tang