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    分区索引知识点拾遗

    小荷发表于 2016-12-14 07:34:49
    love 0

    索引是一般索引还是分区索引,可以看dba_indexes的partitioned字段。

    如果partitioned字段是YES,说明是分区索引,那么,这个索引是global还是local,可以看dba_part_indexes的LOCALITY字段。

    另外,我们还可以看ALIGNMENT字段,看这个索引是基于前导列(prefixed)还是非前导列。(注:global肯定是基于前导列,因为不能建基于非前导列的global索引。而local索引可以基于前导列和非前导列)

    SQL> drop table invoices;
    
    Table dropped.
    
    --创建分区表,是range分区:
    SQL> CREATE TABLE invoices
      2  (invoice_no    NUMBER NOT NULL,
      3   invoice_date  DATE   NOT NULL,
      4   invoice_area varchar2(200),
      5   invoice_serial number,
      6   comments      VARCHAR2(500),
      7   invoice_name varchar2(20)
      8   )
      9  PARTITION BY RANGE (invoice_date)
     10  (PARTITION invoices_q1 VALUES LESS THAN (TO_DATE('01/04/2001', 'DD/MM/YYYY')) TABLESPACE users,
     11   PARTITION invoices_q2 VALUES LESS THAN (TO_DATE('01/07/2001', 'DD/MM/YYYY')) TABLESPACE users,
     12   PARTITION invoices_q3 VALUES LESS THAN (TO_DATE('01/09/2001', 'DD/MM/YYYY')) TABLESPACE users,
     13   PARTITION invoices_q4 VALUES LESS THAN (TO_DATE('01/01/2002', 'DD/MM/YYYY')) TABLESPACE users);
    
    Table created.
    
    SQL>
    SQL> --创建global分区索引,分区类型可以和表一样,也可以不一样。这个索引是和表分区类型一样,但是value less值不一样。
    SQL> CREATE INDEX idx_glob_inv_ser ON invoices (invoice_serial,comments) GLOBAL
      2  PARTITION BY range (invoice_serial)
      3  (PARTITION invoices_q1 VALUES LESS THAN (10) TABLESPACE users,
      4   PARTITION invoices_q2 VALUES LESS THAN (20) TABLESPACE users,
      5   PARTITION invoices_q3 VALUES LESS THAN (30) TABLESPACE users,
      6   PARTITION invoices_q4 VALUES LESS THAN (40) TABLESPACE users,
      7   PARTITION invoices_qmax VALUES LESS THAN (MAXVALUE) TABLESPACE users);
    
    Index created.
    
    SQL>
    SQL> --注意global分区索引,必须使用前导列,及如果索引列是 (comments,invoice_serial),
    SQL> --但partition by xx(invoice_serial)用了非前导列,是会报错,不能创建成功的。
    SQL> CREATE INDEX idx_glob_inv_date ON invoices (comments,invoice_serial) GLOBAL
      2  PARTITION BY hash (invoice_serial) partitions 16;
    PARTITION BY hash (invoice_serial) partitions 16
                                     *
    ERROR at line 2:
    ORA-14038: GLOBAL partitioned index must be prefixed
    
    
    SQL>
    SQL>
    SQL> --创建另一个global分区索引,这个索引的分区类型是和表分区类型不一样的。用了hash分区。但是prefix前导列的原理也是一样的,需要使用前导列。
    SQL> CREATE INDEX idx_glob_inv_date ON invoices (comments,invoice_serial) GLOBAL
      2  PARTITION BY hash (comments) partitions 16;
    
    Index created.
    
    SQL>
    SQL>
    SQL> --创建local索引,注意不能指定partition by的类型的,local索引的分区类型和分区数量必须和table一致,但是可以指定不同的表空间。这个local使用了前导列。
    SQL> CREATE INDEX idx_glo_inv_dt ON invoices (invoice_date,invoice_serial) LOCAL
      2   (PARTITION invoices_q1 TABLESPACE users,
      3    PARTITION invoices_q2 TABLESPACE users,
      4    PARTITION invoices_q3 TABLESPACE users,
      5    PARTITION invoices_q4 TABLESPACE users);
    
    Index created.
    SQL>
    SQL> --如果分区数量必须和table不一致,会报错:
    SQL> CREATE INDEX idx_glo_inv_dt ON invoices (invoice_date,invoice_serial) LOCAL
      2   (PARTITION invoices_q1 TABLESPACE users,
      3    PARTITION invoices_q2 TABLESPACE users,
      4    PARTITION invoices_q3 TABLESPACE users,
      5    PARTITION invoices_q4 TABLESPACE users,
      6    PARTITION invoices_q5 TABLESPACE users);
    CREATE INDEX idx_glo_inv_dt ON invoices (invoice_date,invoice_serial) LOCAL
                                   *
    ERROR at line 1:
    ORA-14024: number of partitions of LOCAL index must equal that of the underlying table
    
    SQL> --创建local索引,注,local索引可以使用非前导列。而global索引只能使用前导列,不能使用非前导列。
    SQL> CREATE INDEX idx_glo_inv_serl ON invoices (invoice_serial,invoice_date) LOCAL
      2   (PARTITION invoices_q1 TABLESPACE users,
      3    PARTITION invoices_q2 TABLESPACE users,
      4    PARTITION invoices_q3 TABLESPACE users,
      5    PARTITION invoices_q4 TABLESPACE users);
    
    Index created.
    SQL>
    SQL> --如果分区数量必须和table不一致,会报错:
    SQL> CREATE INDEX idx_glo_inv_serl ON invoices (invoice_serial,invoice_date) LOCAL
      2   (PARTITION invoices_q1 TABLESPACE users,
      3    PARTITION invoices_q2 TABLESPACE users,
      4    PARTITION invoices_q3 TABLESPACE users,
      5    PARTITION invoices_q4 TABLESPACE users
      6    PARTITION invoices_q5 TABLESPACE users,
      7    PARTITION invoices_q6 TABLESPACE users);
      PARTITION invoices_q5 TABLESPACE users,
      *
    ERROR at line 6:
    ORA-14010: this physical attribute may not be specified for an index partition
    
    
    SQL> 
    SQL> --创建一般索引(即非分区索引):
    SQL> create index idx_glo_inv_comm on invoices (comments);
    
    Index created.
    
    SQL>
    SQL>
    SQL>
    SQL>
    SQL> select index_name,PARTITIONED from dba_indexes where table_name='INVOICES';
    
    INDEX_NAME           PARTIT
    -------------------- ------
    IDX_GLOB_INV_SER     YES
    IDX_GLOB_INV_DATE    YES
    IDX_GLO_INV_DT       YES
    IDX_GLO_INV_SERL     YES
    IDX_GLO_INV_COMM     NO
    
    SQL>
    SQL> select INDEX_NAME,PARTITIONING_TYPE,LOCALITY,ALIGNMENT from dba_part_indexes where table_name='INVOICES';
    
    INDEX_NAME           PARTITIONING_TYPE  LOCALITY     ALIGNMENT
    -------------------- ------------------ ------------ ------------------------
    IDX_GLOB_INV_SER     RANGE              GLOBAL       PREFIXED
    IDX_GLOB_INV_DATE    HASH               GLOBAL       PREFIXED
    IDX_GLO_INV_DT       RANGE              LOCAL        PREFIXED
    IDX_GLO_INV_SERL     RANGE              LOCAL        NON_PREFIXED
    
    SQL>



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