Search Postgresql Archives

Re: question about alternate ordering of results

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



hamann.w@xxxxxxxxxxx writes:
> Now, in versions 8 and later the "using <&-" is rejected,
> the ordering op "needs to be < or > member of a btree operator class". 
> What is needed to create the old behaviour again 
> - create a complete operator class, including new names for the unchanged equals/not equals function?

Yes.  It sounds like you have pretty much all the spare parts you need,
you just have to collect them together into an opclass for each
ordering you want.

> Is this relevant to performance?

Somewhat, in that it helps the planner optimize ordering considerations.
But IIRC the main argument for tightening it up was to catch mistakes
wherein somebody says "ORDER BY x USING &&", or some other operator that
doesn't produce a consistent sort order.

			regards, tom lane

-- 
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux