Oracle在线重分区主键索引

Question

我有一个 24x7 OLTP (11gR2) 应用程序，它可以承受对特定表的大量插入，流量增加到我们遇到严重索引争用的程度。我们对这个特定表上的主键使用序列，为了减少索引争用，我想将主键索引重新分区为具有 8 个哈希分区（当前索引和表未分区）。我可以重建索引以在线方式将其转换为分区，即不停止表上的 DML 吗？

Answer 1

经过深思熟虑，我想我已经做到了。唯一的缺点是您需要将基础表的空间加倍才能这样做......

不要认为还有其他方法可以做到这一点，因为您无法在不删除和重新创建的情况下重新定义 PK（如果我错了，请纠正我）。

PHIL@PHILL11G2 > alter table bigtable add constraint bigtable_pk primary key (object_id);

Table altered.

PHIL@PHILL11G2 > commit;

Commit complete.

PHIL@PHILL11G2 > create table bigtable_interim as ( select * from bigtable where 1=0 );

Table created.

PHIL@PHILL11G2 > EXEC dbms_redefinition.can_redef_table('PHIL', 'BIGTABLE');

PL/SQL procedure successfully completed.

PHIL@PHILL11G2 > exec DBMS_REDEFINITION.start_redef_table(uname =>     'PHIL',orig_table => 'BIGTABLE',int_table => 'BIGTABLE_INTERIM');

PL/SQL procedure successfully completed.

PHIL@PHILL11G2 > 
PHIL@PHILL11G2 > create unique index bigtable_int_hash on bigtable_interim (object_id) global partition by hash (object_id) (partition p1 tablespace users, partition p2 tablespace users) online;

Index created.

PHIL@PHILL11G2 > exec dbms_redefinition.finish_redef_table(uname => 'PHIL',orig_table => 'BIGTABLE',int_table => 'BIGTABLE_INTERIM');

PL/SQL procedure successfully completed.

PHIL@PHILL11G2 > select count(*) from bigtable_interim;

  COUNT(*)
----------
   2300640

PHIL@PHILL11G2 > select count(*) from bigtable;

  COUNT(*)
----------
   2300640

PHIL@PHILL11G2 >
PHIL@PHILL11G2 > alter table bigtable add constraint bigtable_hashed_pk primary key (object_id) ;

Table altered.

PHIL@PHILL11G2 > -- that reused the hashed index i created

随时纠正我犯的任何错误:)

菲尔