b8d43c7d创建于 2022年11月30日历史提交
\c table_name_test_db;
set dolphin.lower_case_table_names TO 0;
create schema analyze_commands;
set search_path to analyze_commands;
drop table if exists T1;
NOTICE:  table "T1" does not exist, skipping
create table T1(a int, b int, c int);
insert into T1 values(generate_series(1,10),generate_series(1,2),generate_series(1,2));
set default_statistics_target=100;
analyze T1;
analyze T1((b,c));
INFO:  Please set default_statistics_target to a negative value to collect extended statistics.
select * from pg_stats where tablename = 'T1' order by attname;
    schemaname    | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs |    histogram_bounds    | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
------------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+------------------------+-------------+-------------------+------------------------+----------------------
 analyze_commands | T1        | a       | f         |         0 |         4 |         -1 |            0 |                  |                   | {1,2,3,4,5,6,7,8,9,10} |           1 |                   |                        | 
 analyze_commands | T1        | b       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
 analyze_commands | T1        | c       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
(3 rows)

select * from pg_catalog.pg_ext_stats;
 schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs | most_common_vals_null | most_common_freqs_null | histogram_bounds 
------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+-----------------------+------------------------+------------------
(0 rows)

drop table if exists T1;
create table T1(a int, b int, c int);
insert into T1 values(generate_series(1,10),generate_series(1,2),generate_series(1,2));
set default_statistics_target=100;
select * from pg_stats where tablename = 'T1' order by attname;
 schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
(0 rows)

select * from pg_catalog.pg_ext_stats;
 schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs | most_common_vals_null | most_common_freqs_null | histogram_bounds 
------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+-----------------------+------------------------+------------------
(0 rows)

drop table if exists T1;
create table T1(a int, b int, c int);
insert into T1 values(generate_series(1,10),generate_series(1,2),generate_series(1,2));
set default_statistics_target=-2;
analyze T1;
analyze T1((b,c));
select * from pg_stats where tablename = 'T1' order by attname;
    schemaname    | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs |    histogram_bounds    | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
------------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+------------------------+-------------+-------------------+------------------------+----------------------
 analyze_commands | T1        | a       | f         |         0 |         4 |         -1 |            0 |                  |                   | {1,2,3,4,5,6,7,8,9,10} |           1 |                   |                        | 
 analyze_commands | T1        | b       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
 analyze_commands | T1        | c       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
(3 rows)

select * from pg_catalog.pg_ext_stats;
    schemaname    | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs | most_common_vals_null | most_common_freqs_null | histogram_bounds 
------------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+-----------------------+------------------------+------------------
 analyze_commands | T1        | 2 3     | f         |         0 |         8 |       -0.2 |            0 |                  |                   |                       |                        | 
(1 row)

insert into T1 values(generate_series(1,10),generate_series(3,4),generate_series(3,4));
select * from pg_stats where tablename = 'T1' order by attname;
    schemaname    | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs |    histogram_bounds    | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
------------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+------------------------+-------------+-------------------+------------------------+----------------------
 analyze_commands | T1        | a       | f         |         0 |         4 |         -1 |            0 |                  |                   | {1,2,3,4,5,6,7,8,9,10} |           1 |                   |                        | 
 analyze_commands | T1        | b       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
 analyze_commands | T1        | c       | f         |         0 |         4 |       -0.2 |            0 | {1,2}            | {0.5,0.5}         |                        |    0.636364 |                   |                        | 
(3 rows)

select * from pg_catalog.pg_ext_stats;
    schemaname    | tablename | attname | inherited | null_frac | avg_width | n_distinct | n_dndistinct | most_common_vals | most_common_freqs | most_common_vals_null | most_common_freqs_null | histogram_bounds 
------------------+-----------+---------+-----------+-----------+-----------+------------+--------------+------------------+-------------------+-----------------------+------------------------+------------------
 analyze_commands | T1        | 2 3     | f         |         0 |         8 |       -0.2 |            0 |                  |                   |                       |                        | 
(1 row)

reset search_path;
drop schema analyze_commands cascade;
NOTICE:  drop cascades to table analyze_commands."T1"