Hi serg, Yes, I had tried that. I had tried many combinations. I have updated the test however on github code: https://github.com/igniting/server/tree/selfTuningOptimizer.
Regards Anshu On Wed, Jun 11, 2014 at 1:13 PM, Sergei Golubchik <[email protected]> wrote: > Hi, Anshu! > > On Jun 11, Anshu Avinash wrote: > > Hi serg, > > > > I have attached the updated diff. I'm still unable to observe the effect > > introduced by the cost factors. Maybe I just need to study the usage of > > scan_time() and read_time() in greater detail. > > Ok, see one suggestion below. If that won't help - push your changes to > github, I'll try myself. > > > diff --git a/mysql-test/r/costmodel.result > b/mysql-test/r/costmodel.result > > new file mode 100644 > > index 0000000..6668758 > > --- /dev/null > > +++ b/mysql-test/r/costmodel.result > > @@ -0,0 +1,20 @@ > > +DROP TABLE IF EXISTS t1; > > +CREATE TABLE t1 (a int auto_increment primary key, b int); > > +INSERT INTO t1(b) values > (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12), > > +(13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25); > > +EXPLAIN > > +SELECT * FROM t1 > > +WHERE a > 21; > > +id select_type table type possible_keys key key_len > ref rows Extra > > +1 SIMPLE t1 range PRIMARY PRIMARY 4 NULL 5 > Using index condition > > +use mysql; > > +UPDATE optimizer_cost_factors > > +SET const_value=2.0 > > +WHERE const_name='SCAN_TIME_FACTOR'; > > +use test; > > +EXPLAIN > > +SELECT * FROM t1 > > +WHERE a > 21; > > +id select_type table type possible_keys key key_len > ref rows Extra > > +1 SIMPLE t1 range PRIMARY PRIMARY 4 NULL 5 > Using index condition > > +DROP TABLE t1; > > See? Your first EXPLAIN already shows type=range. And then you increase > the cost of the table scan. Of course, nothing can happen anymore. > > Try to make the first explain to show type=ALL (which means table scan), > then increase the cost of the table scan and see how optimizer will > switch to type=range. > > Regards, > Sergei > >
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