数据库中间隔分区表的删除逻辑

这篇文章主要介绍了数据库中间隔分区表的删除逻辑，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。

主要讨论如下：
1.间隔分区表的删除逻辑
2.如何处理ORA-14758报错

创建间隔分区
create table t_interval
(
  a DATE,
  b int,
  c int
  )
PARTITION BY RANGE (a)
  INTERVAL (numtodsinterval(3,'day'))
  (
           PARTITION P1 VALUES LESS THAN (TO_DATE('2018-1-2', 'YYYY-MM-DD'))
  );
insert into t_interval values(TO_DATE('2018-01-01 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-02 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-05 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-08 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-11 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-14 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
commit;

09:45:19 SQL>  select PARTITION_NAME,HIGH_VALUE,PARTITION_POSITION,INTERVAL from dba_tab_partitions where table_name='T_INTERVAL';

PARTITION_NAME       HIGH_VALUE                                                                       PARTITION_POSITION INTERVAL
-------------------- -------------------------------------------------------------------------------- ------------------ ---------
P1                   TO_DATE(' 2018-01-02 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  1 NO
SYS_P2876            TO_DATE(' 2018-01-05 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  2 YES
SYS_P2877            TO_DATE(' 2018-01-08 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  3 YES
SYS_P2878            TO_DATE(' 2018-01-11 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  4 YES
SYS_P2879            TO_DATE(' 2018-01-14 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  5 YES
SYS_P2880            TO_DATE(' 2018-01-17 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  6 YES

6 rows selected.
interval列指示分区是否是间隔分区。创建表时指定的分区不属于间隔分区范畴。

更改表的分区间隔
alter table t_interval set interval(NUMTODSINTERVAL(2,'day')); 09:46:57 SQL> select PARTITION_NAME,HIGH_VALUE,PARTITION_POSITION,INTERVAL from dba_tab_partitions where table_name='T_INTERVAL';

PARTITION_NAME       HIGH_VALUE                                                                       PARTITION_POSITION INTERVAL
-------------------- -------------------------------------------------------------------------------- ------------------ ---------
P1                   TO_DATE(' 2018-01-02 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  1 NO
SYS_P2876            TO_DATE(' 2018-01-05 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  2 NO
SYS_P2877            TO_DATE(' 2018-01-08 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  3 NO
SYS_P2878            TO_DATE(' 2018-01-11 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  4 NO
SYS_P2879            TO_DATE(' 2018-01-14 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  5 NO
SYS_P2880            TO_DATE(' 2018-01-17 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  6 NO

6 rows selected.

Elapsed: 00:00:00.00
分区间隔更改之后，interval列都变成了NO。

插入数据产生新分区
insert into t_interval values(TO_DATE('2018-01-18 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-20 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-22 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-24 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-01-26 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
commit; 09:48:55 SQL> select PARTITION_NAME,HIGH_VALUE,PARTITION_POSITION,INTERVAL from dba_tab_partitions where table_name='T_INTERVAL';

PARTITION_NAME       HIGH_VALUE                                                                       PARTITION_POSITION INTERVAL
-------------------- -------------------------------------------------------------------------------- ------------------ ---------
P1                   TO_DATE(' 2018-01-02 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  1 NO
SYS_P2876            TO_DATE(' 2018-01-05 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  2 NO
SYS_P2877            TO_DATE(' 2018-01-08 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  3 NO
SYS_P2878            TO_DATE(' 2018-01-11 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  4 NO
SYS_P2879            TO_DATE(' 2018-01-14 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  5 NO
SYS_P2880            TO_DATE(' 2018-01-17 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  6 NO
SYS_P2881            TO_DATE(' 2018-01-19 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  7 YES
SYS_P2882            TO_DATE(' 2018-01-21 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  8 YES
SYS_P2883            TO_DATE(' 2018-01-23 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                  9 YES
SYS_P2884            TO_DATE(' 2018-01-25 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                 10 YES
SYS_P2885            TO_DATE(' 2018-01-27 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIA                 11 YES

11 rows selected.
新生成的分区属于间隔分区。

尝试删除分区
09:49:26 SQL> alter table t_interval drop partition SYS_P2880;
alter table t_interval drop partition SYS_P2880
                                      *
ERROR at line 1:
ORA-14758: Last partition in the range section cannot be dropped
经过多次尝试之后发现，发现无法删除间隔分区最后一个为NO的分区。

如果一定要删除最后一个为NO的分区的话，那么需要把分区表dba_tab_partitions的interval列都变为NO。
方法很简单，就是指定interval属性为当前值，再执行一遍：
alter table t_interval set interval(NUMTODSINTERVAL(1,'day'));
然后删除
09:55:32 SQL> alter table t_interval drop partition SYS_P2880;

Table altered.

Elapsed: 00:00:00.01
再插入数据产生新的间隔分区
insert into t_interval values(TO_DATE('2018-02-01 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-02-02 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
insert into t_interval values(TO_DATE('2018-02-03 10:00:00', 'YYYY-MM-DD HH24:MI:SS'),1,1);
commit;

抓取表的ddl

set pagesize 0
set long 90000
select dbms_metadata.get_ddl('TABLE','T_INTERVAL','MING') from dual; 10:35:19 SQL> select dbms_metadata.get_ddl('TABLE','T_INTERVAL','MING') from dual;

 
  CREATE TABLE "MING"."T_INTERVAL"
   (    "A" DATE,
        "B" NUMBER(*,0),
        "C" NUMBER(*,0)
   ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
  STORAGE(
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CAC
HE DEFAULT)
  TABLESPACE "TBS_MING"
  PARTITION BY RANGE ("A") INTERVAL (NUMTODSINTERVAL(1,'DAY'))
 (PARTITION "SYS_P2877"  VALUES LESS THAN (TO_DATE(' 20
18-01-08 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_C
ALENDAR=GREGORIAN')) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
 NOCOMPRESS LOGGING
  STORAGE(INITIAL 8388608 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS
2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "TBS_MING" ,
 。。。省略。。。
 PARTITION "SYS_P2890"  VALUES LESS THAN (TO_DATE(' 2018-01-30 00:
00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREG
ORIAN')) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
 NOCOMPRESS LOGGING
  STORAGE(INITIAL 8388608 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE
DEFAULT)
  TABLESPACE "TBS_MING" ,
 PARTITION "SYS_P2891"  VALUES LESS THAN (TO_DATE(' 2018-01-31 00:00
:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGOR
IAN')) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
 NOCOMPRESS LOGGING
  STORAGE(INITIAL 8388608 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DE
FAULT)
  TABLESPACE "TBS_MING" )

会发现间隔分区定义并没有出现在表的ddl定义语句中。当表分区属性interval变为NO后，分区被转变成范围分区，然后才会加入到表的ddl语句中。

1.间隔分区interval为NO的最后一个分区无法删除，都变为NO的时候，则可以删除任意一个分区
2.alter table t_interval set interval命令可以将interval属性都变为NO。
3.间隔分区定义不出现在表的ddl语句中，interval变为NO后，才会加入到表的ddl语句中。

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