指定单分区统计信息收集

当前分区表支持指定单分区统计信息收集，已收集统计信息的分区会在再次收集时自动更新维护。该功能适用于列表分区、哈希分区和范围分区。

gaussdb=# CREATE TABLE only_fisrt_part(id int,name varchar)PARTITION BY RANGE (id) 
 (PARTITION id11 VALUES LESS THAN (1000000),
PARTITION id22 VALUES LESS THAN (2000000),
PARTITION max_id1 VALUES LESS THAN (MAXVALUE));

gaussdb=# INSERT INTO only_fisrt_part SELECT generate_series(1,5000),'test';
 

gaussdb=# ANALYZE only_fisrt_part PARTITION (id11);
gaussdb=# ANALYZE only_fisrt_part PARTITION (id22);
gaussdb=# ANALYZE only_fisrt_part PARTITION (max_id1);

gaussdb=# SELECT relname, relpages, reltuples FROM pg_partition WHERE relname IN ('id11', 'id22', 'max_id1');
 relname | relpages | reltuples 
---------+----------+-----------
 id11    |     3400 |      5000
 id22    |        0 |         0
 max_id1 |        0 |         0
(3 rows)

gaussdb=# \x
gaussdb=# SELECT * FROM pg_stats WHERE tablename ='only_fisrt_part' AND partitionname ='id11';
-[ RECORD 1 ]----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
schemaname             | public
tablename              | only_fisrt_part
attname                | name
inherited              | f
null_frac              | 0
avg_width              | 5
n_distinct             | 1
n_dndistinct           | 0
most_common_vals       | {test}
most_common_freqs      | {1}
histogram_bounds       | 
correlation            | 1
most_common_elems      | 
most_common_elem_freqs | 
elem_count_histogram   | 
partitionname          | id11
subpartitionname       | 
-[ RECORD 2 ]----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
schemaname             | public
tablename              | only_fisrt_part
attname                | id
inherited              | f
null_frac              | 0
avg_width              | 4
n_distinct             | -1
n_dndistinct           | 0
most_common_vals       | 
most_common_freqs      | 
histogram_bounds       | {1,50,100,150,200,250,300,350,400,450,500,550,600,650,700,750,800,850,900,950,1000,1050,1100,1150,1200,1250,1300,1350,1400,1450,1500,1550,1600,1650,1700,1750,1800,1850,1900,1950,2000,2050,2100,2150,2200,2250,2300,2350,2400,2450,2500,2550,2600,2650,2700,2750,2800,2850,2900,2950,3000,3050,3100,3150,3200,3250,3300,3350,3400,3450,3500,3550,3600,3650,3700,3750,3800,3850,3900,3950,4000,4050,4100,4150,4200,4250,4300,4350,4400,4450,4500,4550,4600,4650,4700,4750,4800,4850,4900,4950,5000}
correlation            | 1
most_common_elems      | 
most_common_elem_freqs | 
elem_count_histogram   | 
partitionname          | id11
subpartitionname       |
gaussdb=# q \x
-- 删除分区表
gaussdb=# DROP TABLE only_fisrt_part;