Re: Timeline ID hexadecimal format

From: Sébastien Lardière <sebastien(at)lardiere(dot)net>
To: Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, Greg Stark <stark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Timeline ID hexadecimal format
Date: 2023-03-07 17:14:58
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On 06/03/2023 18:04, Peter Eisentraut wrote:
> On 03.03.23 16:52, Sébastien Lardière wrote:
>> On 02/03/2023 09:12, Peter Eisentraut wrote:
>>> I think here it would be more helpful to show actual examples. Like,
>>> here is a possible file name, this is what the different parts mean.
>> So you mean explain the WAL filename and the history filename ? Is it
>> the good place for it ?
> Well, your patch says, by the way, the timeline ID in the file is
> hexadecimal.  Then one might ask, what file, what is a timeline, what
> are the other numbers in the file, etc.  It seems very specific in
> this context.  I don't know if the format of these file names is
> actually documented somewhere.

Well, in the context of this patch, the usage both filename are
explained juste before, so it seems understandable to me

Timelines are explained in this place :
so the patch explains the format there

>>> This applies to all configuration parameters, so it doesn't need to
>>> be mentioned explicitly for individual ones.
>> Probably, but is there another parameter with the same consequence ?
>> worth it to document this point globally ?
> It's ok to mention it again.  We do something similar for example at
> unix_socket_permissions.  But maybe with more context, like "If you
> want to specify a timeline ID hexadecimal (for example, if extracted
> from a WAL file name), then prefix it with a 0x".

Ok, I've improved the message

>>> Maybe this could be fixed instead?
>> Indeed, and strtoul is probably a better option than sscanf, don't
>> you think ?
> Yeah, the use of sscanf() is kind of weird here.  We have been moving
> the option parsing to use option_parse_int().  Maybe hex support could
> be added there.  Or just use strtoul().

I've made the change with strtoul

About option_parse_int(), actually, strtoint() is used, do we need a
option_parse_ul() fonction ?

patch attached,

best regards,


Attachment Content-Type Size
v5_0001_timelineid_hexadecimal_format.patch text/x-patch 3.4 KB

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