Re: Freeze avoidance of very large table.

On 3/2/16 5:41 PM, Tom Lane wrote:
> Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> writes:
>> On 3/2/16 4:21 PM, Peter Geoghegan wrote:
>>> I think you should commit this. The chances of anyone other than you
>>> and Masahiko recalling that you developed this tool in 3 years is
>>> essentially nil. I think that the cost of committing a developer-level
>>> debugging tool like this is very low. Modules like pg_freespacemap
>>> currently already have no chance of being of use to ordinary users.
>>> All you need to do is restrict the functions to throw an error when
>>> called by non-superusers, out of caution.
>>>
>>> It's a problem that modules like pg_stat_statements and
>>> pg_freespacemap are currently lumped together in the documentation,
>>> but we all know that.
>
>> +1.
>
> Would it make any sense to stick it under src/test/modules/ instead of
> contrib/ ? That would help make it clear that it's a debugging tool
> and not something we expect end users to use.

I haven't looked at it in detail; is there something inherently
dangerous about it?

When I'm forced to wear a DBA hat, I'd really love to be able to find
out what VM status for a large table is. If it's in contrib they'll know
the tool is there; if it's under src then there's about 0 chance of
that. I'd think SU-only and any appropriate warnings would be enough
heads-up for DBAs to be careful with it.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com