Re: Index scan ???

Tourtounis Sotiris dijo: 

> The first attribute is classified in descending order and there are
> indexes on it and to the third atribute respectively. I make some SQL
> questions on them in order to use the created b-trees on the first
> attribute and for 3-4 times there isan index scan on it as it used to
> be. However, after those 3-4 times the database start to use
> sequential scan on this first index.

I don't really believe the query plan simply changes without something
else changing (query or data). Note that different queries _will_ have
different plans: ones will use index, others will not.  Also, concurrent
updates may be altering what you are seeing.  See the FAQ about indexes
not being used.

-- 
Alvaro Herrera ()
"Find a bug in a program, and fix it, and the program will work today.
Show the program how to find and fix a bug, and the program
will work forever" (Oliver Silfridge)