Thread: BUG #11803: avoid "distinct" logic if "limit 1" specified
The following bug has been logged on the website: Bug reference: 11803 Logged by: Korenberg Mark Email address: socketpair@gmail.com PostgreSQL version: 9.3.1 Operating system: Linux Description: In other words, query: select * from tablename order by id limit 1 and query: select distinct * from tablename order by id limit 1 should be planned exactly (as if distinct was not specified) ----------------------- https://github.com/ponyorm/pony/issues/90 http://doc.ponyorm.com/queries.html#comment-1654734639
socketpair@gmail.com writes: > query: > select * from tablename order by id limit 1 > and query: > select distinct * from tablename order by id limit 1 > should be planned exactly (as if distinct was not specified) Seems like a waste of planning cycles to check for this. The uniquification step isn't going to take enough time to be an issue, if only one input row arrives. On the other hand, the added planning logic would contribute some small overhead to *every* query using DISTINCT. regards, tom lane