Re: pgsql: Allow units to be specified in relation option setting value.

On Thu, Aug 28, 2014 at 12:22 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Thu, Aug 28, 2014 at 11:14 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
>>> The patch attached fixes pg_upgrade by putting quotes when generating
>>> reloptions and it passes check-world. I imagine that having quotes by
>>> default in the value of reloptions in pg_class is the price to pay for
>>> supporting units. If this is not considered as a correct approach,
>>> then reverting the patch would be wiser I guess.
>>
>> Ugh. I'm not sure what the best solution is, but I don't think I like
>> that one.
>
> Another approach is to change pg_dump so that it encloses the relopt
> values with single quotes. This is the same approach as what
> pg_dumpall does for database or role-specific settings. Obvious
> drawback of this approach is that it prevents pg_dump with 9.4 or
> before from outputting the restorable dump. Maybe we can live with
> this because there is no guarantee that older version of pg_dump can
> work properly with newer major version of server. But maybe
> someone cannot live with that. Not sure.

To me, this doesn't seem nearly important enough to justify breaking
pg_dump compatibility. AAUI, this is just a cosmetic improvement, so
we shouldn't break functional things for that.

> Further other approach is to change the reloptions code so that it
> always stores the plain value without the units (i.e., 1000 is stored
> if 1s is specified in autovacuum_vacuum_cost_delay)in pg_class.
> This approach doesn't prevent older version of pg_dump from taking
> the dump from v9.5 server. One drawback of this approach is that
> reloption values are always stored without the units, which might
> make it a bit hard for a user to see the reloption values from pg_class.

This seems like the way to go.

--
Robert Haas
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