Oracle的hash分区

创建hash分区：

create table hash_part_tab (id number,deal_date date,area_code number,nbr number,contents varchar2(4000))
partition by hash (deal_date)
PARTITIONS 12 tablespace big01

插入数据:

insert into hash_part_tab(id,deal_date,area_code,nbr,contents)
select rownum,
to_date( to_char(sysdate-365,'J')+TRUNC(DBMS_RANDOM.VALUE(0,365)),'J'),
ceil(dbms_random.value(590,599)),
ceil(dbms_random.value(18900000001,18999999999)),
rpad('*',400,'*')
from dual
connect by rownum <= 100000;
commit;

查看分区名称：

select partition_name,
segment_type,
bytes,
'select count(*) from hash_part_tab partition('||partition_name||');'
from user_segments
where segment_name ='HASH_PART_TAB';

创建索引：

create index idx_hash_part_id on hash_part_tab (id) ;
create index idx_hash_part_nbr on hash_part_tab (nbr) local;

收集统计信息：

exec dbms_stats.gather_table_stats(ownname => 'SYS',tabname => 'HASH_PART_TAB',estimate_percent => 10,method_opt=> 'for all indexed columns',cascade=>TRUE) ;

该表是否是分区表，分区表的分区类型是什么，是否有子分区，分区总数有多少:

select partitioning_type,subpartitioning_type,partition_count from user_part_tables where table_name='HASH_PART_TAB';

该分区表在哪一列上建分区,有无多列联合建分区:

select column_name,
object_type,
column_position
from user_part_key_columns
where name ='HASH_PART_TAB';

--该分区表有多大：

select sum(bytes) / 1024 / 1024
from user_segments
where segment_name ='HASH_PART_TAB';

该分区表各分区分别有多大，各个分区名是什么:

select partition_name,
segment_type,
bytes
from user_segments
where segment_name ='HASH_PART_TAB';

该分区表的统计信息收集情况:

select table_name,
partition_name,
last_analyzed,
partition_position,
num_rows
from user_tab_statistics t
where table_name ='HASH_PART_TAB';

查该分区表有无索引，分别什么类型,全局索引是否失效，此外还可看统计信息收集情况：

select table_name,
index_name,
last_analyzed,
blevel,
num_rows,
leaf_blocks,
distinct_keys,
status
from user_indexes
where table_name ='HASH_PART_TAB';

该分区表在哪些列上建了索引:

select index_name,
column_name,
column_position
from user_ind_columns
where table_name = 'HASH_PART_TAB';

该分区表上的各索引分别有多大：

select segment_name,segment_type,sum(bytes)/1024/1024
from user_segments
where segment_name in
(select index_name
from user_indexes
where table_name ='HASH_PART_TAB')
group by segment_name,segment_type ;

该分区表的索引段的分配情况:

select segment_name
partition_name,
segment_type,
bytes
from user_segments
where segment_name in
(select index_name
from user_indexes
where table_name ='HASH_PART_TAB');

分区索引相关信息及统计信息、是否失效查看:

select t2.table_name,
t1.index_name,
t1.partition_name,
t1.last_analyzed,
t1.blevel,
t1.num_rows,
t1.leaf_blocks,
t1.status
from user_ind_partitions t1, user_indexes t2
where t1.index_name = t2.index_name
and t2.table_name='HASH_PART_TAB';