postgresql 10.1 分区表之 range 分区

查看数据库版本

select version();
PostgreSQL 10.1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18), 64-bit

create table语法

CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name ( [
  { column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
    | table_constraint
    | LIKE source_table [ like_option ... ] }
    [, ... ]
] )
[ INHERITS ( parent_table [, ... ] ) ]
[ PARTITION BY { RANGE | LIST | HASH } ( { column_name | ( expression ) } [ COLLATE collation ] [ opclass ] [, ... ] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]

CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name
    OF type_name [ (
  { column_name [ WITH OPTIONS ] [ column_constraint [ ... ] ]
    | table_constraint }
    [, ... ]
) ]
[ PARTITION BY { RANGE | LIST | HASH } ( { column_name | ( expression ) } [ COLLATE collation ] [ opclass ] [, ... ] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]

CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name
    PARTITION OF parent_table [ (
  { column_name [ WITH OPTIONS ] [ column_constraint [ ... ] ]
    | table_constraint }
    [, ... ]
) ] { FOR VALUES partition_bound_spec | DEFAULT }
[ PARTITION BY { RANGE | LIST | HASH } ( { column_name | ( expression ) } [ COLLATE collation ] [ opclass ] [, ... ] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]



and partition_bound_spec is:

IN ( { numeric_literal | string_literal | NULL } [, ...] ) |
FROM ( { numeric_literal | string_literal | MINVALUE | MAXVALUE } [, ...] )
  TO ( { numeric_literal | string_literal | MINVALUE | MAXVALUE } [, ...] ) |
WITH ( MODULUS numeric_literal, REMAINDER numeric_literal )

rang 分区
创建分区主表 drop table tmp_par_range

drop table tmp_par_range;

create table tmp_par_range ( 
  id int8,
  random_char varchar(100),
  day_id varchar(8)
) partition by RANGE(day_id);

创建分区从表
When creating a range partition, the lower bound specified with FROM is an inclusive bound, whereas the upper bound specified with TO is an exclusive bound. That is, the values specified in the FROM list are valid values of the corresponding partition key columns for this partition, whereas those in the TO list are not.
Note that this statement must be understood according to the rules of row-wise comparison (Section 9.23.5). For example, given PARTITION BY RANGE (x,y), a partition bound FROM (1, 2) TO (3, 4) allows x=1 with any y>=2, x=2 with any non-null y, and x=3 with any y<4.

– from >=
– to <

CREATE TABLE tmp_par_range_p20171130_b PARTITION OF tmp_par_range FOR VALUES FROM (MINVALUE)  TO ('20171130');
CREATE TABLE tmp_par_range_p20171201   PARTITION OF tmp_par_range FOR VALUES FROM ('20171130') TO ('20171201');
CREATE TABLE tmp_par_range_p20171202   PARTITION OF tmp_par_range FOR VALUES FROM ('20171201') TO ('20171202');
CREATE TABLE tmp_par_range_p20171203   PARTITION OF tmp_par_range FOR VALUES FROM ('20171202') TO ('20171203');
CREATE TABLE tmp_par_range_p20171203_a PARTITION OF tmp_par_range FOR VALUES FROM ('20171203') TO (MAXVALUE);

创建索引

create index idx_tmp_par_range_p20171130_b_x1 on tmp_par_range_p20171130_b(day_id);
create index idx_tmp_par_range_p20171201_x1   on tmp_par_range_p20171201(day_id);
create index idx_tmp_par_range_p20171202_x1   on tmp_par_range_p20171202(day_id);
create index idx_tmp_par_range_p20171203_x1   on tmp_par_range_p20171203(day_id);
create index idx_tmp_par_range_p20171203_a_x1 on tmp_par_range_p20171203_a(day_id);

插入数据

insert into tmp_par_range 
select *
from (
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171129' as day_id 
	union all
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171130' as day_id 
	union all
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171201' as day_id 
	union all
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171202' as day_id 
	union all
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171203' as day_id 
	union all
	select generate_series(1, 5) as id, md5(random()::text) as info , '20171204' as day_id 
    ) t0
;

查看数据

select * from tmp_par_range  order by day_id,id ;

select * from public.tmp_par_range_p20171130_b;
select * from public.tmp_par_range_p20171201;
select * from public.tmp_par_range_p20171202;
select * from public.tmp_par_range_p20171203;
select * from public.tmp_par_range_p20171203_a;

查看执行计划

explain
select *
  from tmp_par_range tp
 where 1=1
 
Append  (cost=0.00..64.00 rows=1400 width=260)
  ->  Seq Scan on tmp_par_range_p20171130_b tp  (cost=0.00..12.80 rows=280 width=260)
  ->  Seq Scan on tmp_par_range_p20171201 tp_1  (cost=0.00..12.80 rows=280 width=260)
  ->  Seq Scan on tmp_par_range_p20171202 tp_2  (cost=0.00..12.80 rows=280 width=260)
  ->  Seq Scan on tmp_par_range_p20171203 tp_3  (cost=0.00..12.80 rows=280 width=260)
  ->  Seq Scan on tmp_par_range_p20171203_a tp_4  (cost=0.00..12.80 rows=280 width=260)
 

explain
select *
  from tmp_par_range tp
 where 1=1
   and tp.day_id='20171201'

Append  (cost=0.15..8.17 rows=1 width=260)
  ->  Index Scan using idx_tmp_par_range_p20171202_x1 on tmp_par_range_p20171202 tp  (cost=0.15..8.17 rows=1 width=260)
        Index Cond: ((day_id)::text = '20171201'::text)

explain
select *
  from tmp_par_range tp
 where 1=1
   and tp.day_id in ( '20171201' , '20171202')
   
Append  (cost=0.00..27.00 rows=6 width=260)
  ->  Seq Scan on tmp_par_range_p20171202 tp  (cost=0.00..13.50 rows=3 width=260)
        Filter: ((day_id)::text = ANY ('{20171201,20171202}'::text[]))
  ->  Seq Scan on tmp_par_range_p20171203 tp_1  (cost=0.00..13.50 rows=3 width=260)
        Filter: ((day_id)::text = ANY ('{20171201,20171202}'::text[]))
        

参考:
https://www.postgresql.org/docs/devel/static/sql-createtable.html