Re: ALTER TABLE .. SET SCHEMA lock strength

On Sat, Jan 1, 2011 at 4:24 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
> On lör, 2011-01-01 at 13:17 -0500, Tom Lane wrote:
>> ALTER RENAME and ALTER SET SCHEMA are both in the nature of changing the
>> object's identity.  Consider the fairly typical use-case where you are
>> renaming an "old" instance out of the way and renaming another one into
>> the same schema/name.  Do you really want that to be a low-lock
>> operation?  I find it really hard to envision a use case where it'd be
>> smart to allow some concurrent operations to continue using the the old
>> instance while others start using the new one.
>
> At least in Unix land, that's a handy property.  And we're frequently
> cursing those other operating systems where it doesn't work that way.

Yeah, exactly.  If someone is renaming an old instance out of the way
and sticking a new one in its place, the LAST thing you want to do is
lock out queries unnecessarily.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company