"Tom Lane" <[EMAIL PROTECTED]> writes:

> It's possible that MS-SQL is doing something analogous to the
> hashed-subplan approach (hopefully with suitable tweaking for the NULL
> case) but even then it's hard to see how it could take only 9 sec.
> The cartesian product is too big.

Fwiw it seems MS-SQL is doing something funny. The three plans posted in the
screenshots for the "small", "mediu", and "large" cases are:

Top
        Sort (Distinct Sort)
                Nested Loop (Left Anti Semi Join)
                        Nested Loop
                                Table Scan
                                Table Scan
                        Top
                                Table Scan



[cut off by the screenshot] Match
        Hash Match (Right Anti Semi Join)
                Table Scan
                Nested Loop
                        Table Scan
                        Table Scan



Hash Match (Right Anti Semi Join)
        Parallelism (Repartition Streams)
                Table Scan
        Parallelism (Repartition Streams)
                Nested Loop (Inner Join)
                        Table Scan
                        Table Spool (Lazy Spool)
                                Table Scan


Postgres is doing something equivalent to the first plan.
             
-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Get trained by Bruce Momjian - ask me about EnterpriseDB's PostgreSQL 
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