On 10 November 2016 at 07:18, Clifford Hammerschmidt
<tanglebones@gmail.com> wrote:
>
> On Tue, Nov 8, 2016 at 2:58 PM, Craig Ringer <craig.ringer@2ndquadrant.com>
> wrote:
>>
>> 2ndQuadrant/bdr
>
>
> That is similar. I'm not clear on the usage of OID for sequence
> (`DirectFunctionCall1(nextval_oid, seqoid)`) ... does that imply a lock
> around a sequence generation? also different is that your sequence doesn't
> reset on the time basis, it ascends and wraps independently of the time.
Meant to explain more here.
Most of the system identifies sequence relations by oid. All this does
is call nextval. By accepting and passing oid we reduce the number of
syscache/relcache lookups and memory allocations required to call
nextval vs calling it by name. That's about all, really.
-- Craig Ringer http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Remote DBA, Training
&Services