Does PREPARE turn select * from mytable into select mytable.field1,mytable.field2 from mynamespace.mytable ?
I was looking for this functionality for one of my projects so I'm curious. On Monday 28 October 2002 06:55 pm, (Via wrote: > That is a good question. The planner does more than just analyse the > query. It generates the Plan used by the executor, so that can't be > removed. > > It is always a pain when the optimizer/planner takes longer than the > executor. We do have PREPARE/EXECUTE in 7.3beta for you to use. > > > --------------------------------------------------------------------------- > > Ben McMahan wrote: > > I'm looking at different ways of optimizing queries with a large number > > of joins. I write the same query in a number of different ways and > > compare the running times. Now the problem is I do not want the > > optimizer changing the queries. So I explicit state the order of the > > joins in the FROM clause. I also turn off everything I can except for > > one type of join (say hash join), and I've turned off geqo. But I find > > that the PLANNER still takes an enormous amount of time for some queries. > > It doesn't look like the Planner is actually optimizing (changing) > > anything, but just in case, I was wondering if there was a way to turn > > off the PLANNER. > > > > Note, when I say an enormous amount of time, I mean at least double the > > time the EXECUTOR takes to actually answer the query. > > > > Thanks for your help, > > > > Ben McMahan > > > > ps. here is a small example of what my queries look like (so you can see > > if there is something else it might be deciding on): > > > > SELECT DISTINCT c0.x1 , c1.x2 , c0.x3 , c0.x4 , c2.x5 > > FROM r1 c4 (x4,x2,x5) JOIN (r0 c3 (x2,x3,x5) JOIN (r2 c2 (x3,x1,x5) JOIN > > (r1 c1 (x4,x1,x2) JOIN r1 c0 (x1,x3,x4) > > ON ( c0.x4 = c1.x4 AND c0.x1 = c1.x1 )) > > ON ( c0.x3 = c2.x3 AND c0.x1 = c2.x1 )) > > ON ( c1.x2 = c3.x2 AND c0.x3 = c3.x3 AND c2.x5 = c3.x5 )) > > ON ( c0.x4 = c4.x4 AND c1.x2 = c4.x2 AND c2.x5 = c4.x5 ); > > > > A quick reminder, FROM r1 c4 (x4,x2,x5) just renames a table r1 into c4 > > where it also renames the columns to x4, x2, and x5 respectively. > > > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 3: if posting/reading through Usenet, please send an appropriate > > subscribe-nomail command to [EMAIL PROTECTED] so that your > > message can get through to the mailing list cleanly ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster