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.
--
Jim C. Nasby, Database Architect j...@nasby.net
512.569.9461 (cell) http://jim.nasby.net
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