Re: pg_verify_checksums -d option (was: Re: pg_verify_checksums -r option)

> On 27 Aug 2018, at 14:05, Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp> wrote:
>
> On Mon, 27 Aug 2018 13:34:12 +0200
> Michael Banck <michael(dot)banck(at)credativ(dot)de> wrote:
>
>> Hi,
>>
>> On Mon, Aug 27, 2018 at 07:53:36PM +0900, Yugo Nagata wrote:
>>> On Fri, 24 Aug 2018 18:01:09 +0200
>>> Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:
>>>> I'm curious about this option:
>>>>
>>>> -r RELFILENODE check only relation with specified relfilenode
>>>>
>>>> but there is no facility to specify a database.
>>>>
>>>> Also, referring to the relfilenode of a mapped relation seems a bit
>>>> inaccurate.
>>>>
>>>> Maybe reframing this in terms of the file name of the file you want
>>>> checked would be better?
>>>
>>> If we specified 1234 to -r option, pg_verify_shceksums checks not only 1234
>>> but also 1234_vm, 1234_fsm, and 1234.1, 1234.2, ... and so on, so I think
>>> it makes senses to allow to specify a relfilenode instead of a file name.
>>>
>>> I think it is reasonable to add a option to specify a database, although
>>> I don't know which character is good because both -d and -D are already used....
>>
>> Maybe the -d (debug) option should be revisited as well. Mentioning
>> every scanned block generates a huge amount of output which might be
>> useful during development but does not seem very useful for a stable
>> release. AFAICT there is no other debug output for now.
>>
>> So it could be renamed to -v (verbose) and only mention each scanned
>> file, e.g. (errors/checksum mismatches are still reported of course).
>>
>> Then -d could (in the future, I guess that is too late for v11) be used
>> for -d/--dbname (or make that only a long option, if the above does not
>> work).
>
> I realized after sending the previous post that we can not specify a database
> by name because pg_verify_checksum is run in offline and this can not get the
> OID from the database name. Also, there are global and pg_tblspc directories
> not only base/<database OID>. So, it seems to me good to specify a directories
> to scan which is under PGDATA. We would be able to use -d ( or --directory ?)
> for this purpose.

Changing functionality to the above discussed is obviously 12 material, but
since we are discussing changing the command line API of the tool by
repurposing -d; do we want to rename the current use of -d to -v (with the
accompanying —-verbose) before 11 ships? It’s clearly way way too late in the
cycle but it seems worth to at least bring up since 11 will be the first
version pg_verify_checksums ship in. I’m happy to do the work asap if so.

FWIW, personally I think verbose makes more sense for the output than debug.

cheers ./daniel