rowid_filter: negative access cost factor values

commit 58cd0bd59ef011be54f162237f2ff017c3148e7b (HEAD -> 10.4)

Author: Igor Babaev <igor@askmonty.org>

Date:   Mon Oct 17 16:44:10 2022 -0700

    MDEV-28846 Poor performance when rowid filter contains no elements

    When a range rowid filter was used with an index ref access the cost of

    accessing the index entries for the records rejected by the filter was not

    taken into account. For a ref access by an index with big average number

    of records per key this led to poor execution plans if selectivity of the

    used filter was high.

diff --git a/sql/rowid_filter.cc b/sql/rowid_filter.cc

index 75f2ab71ecd..e0673640deb 100644

--- a/sql/rowid_filter.cc

+++ b/sql/rowid_filter.cc

@@ -468,6 +468,9 @@ TABLE::best_range_rowid_filter_for_partial_join(uint access_key_no,

                                                 double records,

                                                 double access_cost_factor)

 {

+  if (access_cost_factor < 0.0)

+    fprintf(stderr, "access_cost_factor=%g query:%s\n", access_cost_factor,

+    current_thd->query());

   if (range_rowid_filter_cost_info_elems == 0 ||

       covering_keys.is_set(access_key_no))

     return 0;

./mysql-test-run main/*filter*test

grep -rn access_cost_factor var/

var/log/bootstrap.log:70:access_cost_factor=-0.00954473 query:SET @broken_routines = (select count(*) from mysql.proc where db='performance_schema');

var/log/mysqld.1.err:51:access_cost_factor=-0.00760976 query:select 1

var/log/mysqld.1.err:57:access_cost_factor=-0.00214634 query:select 1

var/log/mysqld.1.err:63:access_cost_factor=-0.392596 query:select 1

var/log/mysqld.1.err:69:access_cost_factor=-0.00760976 query:explain extended select 1

var/log/mysqld.1.err:75:access_cost_factor=-0.00214634 query:explain extended select 1

var/log/mysqld.1.err:81:access_cost_factor=-0.392596 query:explain extended select 1

var/log/mysqld.1.err:87:access_cost_factor=-0.00214634 query:SELECT * FROM t1 HAVING (7, 9) IN (SELECT t2.i1, t2.i2 FROM t2 WHERE t2.i1 = 3)

var/log/mysqld.1.err:89:access_cost_factor=-0.00214634 query:EXPLAIN EXTENDED

var/log/mysqld.1.err:91:access_cost_factor=-0.00214634 query:EXPLAIN EXTENDED

var/log/mysqld.1.err:93:access_cost_factor=-0.301951 query:SELECT * FROM t1 INNER JOIN t2 ON ( pk1+1 = pk2+2 AND a1 = a2 )

var/log/mysqld.1.err:95:access_cost_factor=-0.0263959 query:SELECT * FROM t1 INNER JOIN t2 ON ( pk1+1 = pk2+2 AND a1 = a2 )

var/log/mysqld.1.err:97:access_cost_factor=-0.301951 query:EXPLAIN EXTENDED SELECT * FROM t1 INNER JOIN t2 ON ( pk1+1 = pk2+2 AND a1 = a2 )

var/log/mysqld.1.err:99:access_cost_factor=-0.0263959 query:EXPLAIN EXTENDED SELECT * FROM t1 INNER JOIN t2 ON ( pk1+1 = pk2+2 AND a1 = a2 )