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MDEV-26849: JSON Histograms: point selectivity estimates are off

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.. for non-existent values.

Handle this special case.
This commit is contained in:
Sergei Petrunia
2021-10-22 19:43:19 +03:00
parent f3f78bed85
commit 05877df472
8 changed files with 142 additions and 10 deletions
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22
mysql-test/main/statistics_json.test
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@ -295,3 +295,25 @@ select c from t1 where c > '1';
drop table t1;
--echo #
--echo # MDEV-26849: JSON Histograms: point selectivity estimates are off for non-existent values
--echo #
--echo #
create table t0(a int);
insert into t0 (a) values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1(a int);
insert into t1 select 100*A.a from t0 A, t0 B, t0 C;
select a, count(*) from t1 group by a order by a;
set histogram_type=json_hb, histogram_size=default;
analyze table t1 persistent for all;
select * from mysql.column_stats where table_name='t1';
analyze select * from t1 where a=0;
analyze select * from t1 where a=50;
analyze select * from t1 where a=70;
analyze select * from t1 where a=100;
analyze select * from t1 where a=150;
analyze select * from t1 where a=200;
drop table t0,t1;