default_statistics_target

• 17
• 16
• 15
• 14
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• 12
• 11
• 10
• 9.6
• 9.5
• 9.4
• 9.3
• 9.2
• 9.1
• 9.0
• 8.4
• 8.3
• 8.2

default_statistics_target 的基本用法示例

postgres=# CREATE TABLE foo (id INT);
CREATE TABLE

postgres=# INSERT INTO foo VALUES(generate_series(1,101));
INSERT 0 101

postgres=# SHOW default_statistics_target;
 default_statistics_target 
---------------------------
 100
(1 row)

postgres=# ANALYZE foo;
ANALYZE

postgres=# SELECT stavalues1
             FROM pg_statistic
            WHERE starelid = 'foo'::regclass\gx
-[ RECORD 1 ]---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
stavalues1 | {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101}

postgres=# SET default_statistics_target TO 10;
SET

postgres=# ANALYZE foo;
ANALYZE

postgres=# SELECT stavalues1
             FROM pg_statistic
            WHERE starelid = 'foo'::regclass\gx
-[ RECORD 1 ]----------------------------------
stavalues1 | {1,11,21,31,41,51,61,71,81,91,101}

• PostgreSQL 文档： default_statistics_target