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  1. MariaDB Server
  2. MDEV-7674

ANALYZE shows r_rows=0

        Details

        • Type: Bug
        • Status: Closed
        • Priority: Major
        • Resolution: Fixed
        • Affects Version/s: 10.1.3
        • Fix Version/s: 10.1.4
        • Component/s: Optimizer
        • Labels:

          Description

          ANALYZE-stmt may print 0 in r_rows column:

          create table t1(a int);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2 (a int, key(a));
insert into t2 values (0),(1);
analyze select * from t1 straight_join t2 force index(a) where t2.a=t1.a;
id     select_type     table   type    possible_keys   key     key_len ref     rows    r_rows  filtered        r_filtered      Extra
1      SIMPLE  t1      ALL     NULL    NULL    NULL    NULL    10      10      100.00  100.00  Using where
1      SIMPLE  t2      ref     a       a       5       test.t1.a       2       0       100.00  100.00  Using index

          this happens when some index lookups do not yield a row.
          We should change r_rows to show fractions.

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                  • Assignee:
                    psergey Sergei Petrunia
                    Reporter:
                    psergey Sergei Petrunia
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                      Updated:
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