Thank you for your answer. Now i ve to find how to reduce the size of the table. Paul. Le mardi 28 août 2007 à 12:55 -0400, Tom Lane a écrit : > Paul <paul@xxxxxxxx> writes: > > Why in the first case, pgsql uses the "better" index and if i search > > r_service instead of r_numero pgsql does a "Bitmap Heap scan" first ? > > Given the difference in the number of rows to be fetched, both plan > choices look pretty reasonable to me. If you want to experiment, > you can try forcing the other choice in each case (use enable_indexscan > and enable_bitmapscan) and see how fast it is, but I suspect the planner > got it right. > > Beware of cache effects when trying two plans in quick succession --- > the second one might go faster just because all the data is already > swapped in. > > regards, tom lane > ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
