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Address review input

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This commit is contained in:
Sergei Petrunia
2021-09-11 19:43:08 +03:00
parent cf8927e9cb
commit 382250c05c
4 changed files with 78 additions and 4 deletions
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48
mysql-test/main/statistics_json.result
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@ -7397,3 +7397,51 @@ id select_type table type possible_keys key key_len ref rows r_rows filtered r_f
set histogram_type=@save_histogram_type;
set histogram_size=@save_histogram_size;
DROP SCHEMA world;
use test;
create table t10 (
a varchar(10)
);
#
# Histograms are not collected for empty tables:
#
analyze table t10 persistent for all;
Table Op Msg_type Msg_text
test.t10 analyze status Engine-independent statistics collected
test.t10 analyze status Table is already up to date
select histogram
from mysql.column_stats where table_name='t10' and db_name=database();
histogram
NULL
#
# Try with n_buckets > n_rows
#
insert into t10 values ('Berlin'),('Paris'),('Rome');
set histogram_size=10, histogram_type='json_hb';
analyze table t10 persistent for all;
Table Op Msg_type Msg_text
test.t10 analyze status Engine-independent statistics collected
test.t10 analyze status OK
select histogram
from mysql.column_stats where table_name='t10' and db_name=database();
histogram
{
"histogram_hb_v2": [
{
"start": "Berlin",
"size": 0.333333333,
"ndv": 1
},
{
"start": "Paris",
"size": 0.333333333,
"ndv": 1
},
{
"start": "Rome",
"end": "Rome",
"size": 0.333333333,
"ndv": 1
}
]
}
drop table t10;