Hello,

I have a table with 5.900.000 records and a unique index on one
column. Firebird 1.53.
I execute the following statement 'select count (*) from table'.

The execution plan informs that the index is not used (Ok, not really
an issue in this case). But the response time is always different and
deos not seem to follow any rule (I expected it will decrease and
take advantage of cached data).

Some example:
1st execution takes 2.01 sec.
2nd : 7.43 sec
3rd : 8.54 sec
4th : 3.04 sec
5th : 2.03 sec
6th : 2.02 sec

Note that no other process was running on the PC.
How do you explain the response time increases and decreases?

Thanks
Christophe Brunin.