Subject Re: [firebird-support] Question about PLANs
Author sugi
> The optimizer recalculates plan on every statement thus if content has
> changed then the PLAN can change too. Note! That selectivity what optimizer
> uses to calculate cost is not updated after every insert/delete. That means
> it could be that selectivity value is not accurate. Although the change
> between 5 and 15 records is not big ;-). You can force recalculate of index
> with SET STATISTICS statement if needed.
I need some confirmation on this: If the 'index selectivity' is not
recalculated after insert/delete, does this mean that we have to
manually issue 'set statistics' every now and then? Or is there any
automatic recalcuation behind the screen?