I am trying to simulate a plan recompilation due to auto update stats which is triggered when threshold(500 + 20 percent modifications) reached.

database current settings are:

enter image description here

I started with creating a simple table:

create table recomp(num int)

Then I insert some rows:

insert into recomp
values (5)
go 100

and run my query below 5 times (I used where 1 = (select 1)) for full optimization:

select * from recomp
where 1 = (select 1)

in my plan cache I have the following:

enter image description here

Now the interesting part, I again insert new rows in order to trigger auto update stats for num column of the recomp table:

insert into recomp
values (8)
go 500

Here stats for num column has updated. The next what I am going to do is run my select query:

select * from recomp
where 1 = (select 1)

When I check my plan cache:

enter image description here

and an event which captures recompiles:

enter image description here

my question is: where can I find stats for num column?

enter image description here

1 Answer 1


The optimizer doen't need any stats to optimize those queries, so none are created.

When the automatic create statistics option, AUTO_CREATE_STATISTICS is ON, the Query Optimizer creates statistics on individual columns in the query predicate, as necessary, to improve cardinality estimates for the query plan.


Try something like

select *
from recomp
where num = 4

And you should see a statistic created.

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