I was thinking in something independent from the executor, simply a variable that recommends or not the use of a particular index, it could be obtained from user, and so it could be improved(a factor lower than 1) on planner. How about something like this?
----- Original Message ----- From: "Bruce Momjian" <[EMAIL PROTECTED]> To: "Luis Alberto Amigo Navarro" <[EMAIL PROTECTED]> Cc: "Lincoln Yeoh" <[EMAIL PROTECTED]>; "Tom Lane" <[EMAIL PROTECTED]>; "mlw" <[EMAIL PROTECTED]>; "Andrew Sullivan" <[EMAIL PROTECTED]>; "PostgreSQL-development" <[EMAIL PROTECTED]> Sent: Tuesday, April 23, 2002 6:42 PM Subject: Re: [HACKERS] Index Scans become Seq Scans after VACUUM ANALYSE > Luis Alberto Amigo Navarro wrote: > > Hi All. > > I've been reading all the thread and I want to add a few points: > > > > You can set enable_seqscan=off in small or easy queries, but in large > > queries index can speed parts of the query and slow other, so I think it is > > neccesary if you want Postgres to become a Wide-used DBMS that the planner > > could be able to decide accuratelly, in the thread there is a point that > > might be useful, it will be very interesting that the planner could learn > > with previous executions, even there could be a warm-up policy to let > > planner learn about how the DB is working, this info could be stored with DB > > data, and could statistically show how use of index or seqscan works on > > every column of the DB. > > Yes, I have always felt it would be good to feed back information from > the executor to the optimizer to help with later estimates. Of course, > I never figured out how to do it. :-) > > -- > Bruce Momjian | http://candle.pha.pa.us > [EMAIL PROTECTED] | (610) 853-3000 > + If your life is a hard drive, | 830 Blythe Avenue > + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 > ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]