2006/12/5, Tom Lane <tgl@xxxxxxxxxxxxx>:
These sorts of reports would be far more helpful if they contained some specifics. What queries does MSSQL do better than Postgres, exactly?
You are of course correct, Tom. I'm sorry I'm not in a position to replay what I've been doing a year ago...I wish I could. Obviously, I never had to worry about the concepts of vacuuming and analysis (not that it's very difficult with pgsql: it just doesn't exist as a concept with MSSQL). Anyone calling my comment completely subjective would be completely correct because that's what it was. One type of query does come to mind, now that I think about it. pgsql has trouble handling queries like SELECT * FROM t0 WHERE t0.id_t1 IN (SELECT t1.id FROM t1 WHERE...) The performance is a bit better when there's only one result in the subselect so you can do: SELECT * FROM t0 WHERE t0.id_t1 = (SELECT t1.id FROM t1 WHERE...) When the subselect returns a lot of results, pgsql really takes it's time. The first query, however, can be executed much, much (at least an order of magnitude) quicker like this: SELECT * FROM t0 LEFT OUTER JOIN t1 ON t1.id = t0.id_t1 WHERE t1.id IS NOT NULL I didn't notice this kind of sensitivity with MSSQL, but again, I can't easily reproduce what I've been doing. Sorry for the original FUD-like report. Cheers, t.n.a.
