On 5/2/12 10:58 PM, Jim Nasby wrote:
> On 4/29/12 6:03 AM, Simon Riggs wrote:
>>> The DML-WITH-LIMIT-1 is required to do single logical updates on tables
>>> > with non-unique rows.
>>> > And as for any logical updates we will have huge performance problem
>>> > when doing UPDATE or DELETE on large table with no indexes, but
>>> > fortunately this problem is on slave, not master;)
>> While that is possible, I would favour the do-nothing approach. By
>> making the default replication mode = none, we then require a PK to be
>> assigned before allowing replication mode = on for a table. Trying to
>> replicate tables without PKs is a problem that can wait basically.
>>
>
> Something that a in-core method might be able to do that an external one
> can't would be to support a method of uniquely identifying rows in
> tables with no PK's. A gross example (that undoubtedly wouldn't work in
> the real world) would be using TID's. A real-world implementation might
> be based on a hidden serial column.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com