問題描述：

經常有人問，我分割槽表裡的索引到底是分割槽索引還是非分割槽索引？

因為是否是分割槽索引涉及到detach分割槽的時候是否會耗費大量的時間做非同步索引清理：如果是非分割槽索引，則非同步索引清理需要大量時間。

總體結論：

--對於唯一索引或者主健，如果包含了分割槽健，則預設是分割槽索引；如果不包含分割槽健，則預設是非分割槽索引。
--對於非唯一索引，預設都是分割槽索引。
 

測試過程

DB2版本為10.5

$ db2 "create table p1 (col1 int not null,col2 int not null,col3 int not null) partition by range(col2)(partition part1 starting 1 ending 5,partition part2 starting 6 ending 10,partition part3 starting 11 ending 15)"

1. 唯一索引

$ db2 "create unique index u_idx1 on p1 (col1)"
$ db2 "create unique index u_idx1_2 on p1 (col1,col2)"
$ db2 "create unique index u_idx1_3 on p1 (col1,col3)"
$ db2look -d sample -a -e -t p1

CREATE UNIQUE INDEX "DB2TST  "."U_IDX1" ON "DB2TST  "."P1" 
                ("COL1" ASC)
                NOT PARTITIONED IN "TBS2"

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;

-- DDL Statements for Indexes on Table "DB2TST  "."P1"

SET SYSIBM.NLS_STRING_UNITS = 'SYSTEM';

CREATE UNIQUE INDEX "DB2TST  "."U_IDX1_2" ON "DB2TST  "."P1" 
                ("COL1" ASC,"COL2" ASC)
                PARTITIONED

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;

-- DDL Statements for Indexes on Table "DB2TST  "."P1"

SET SYSIBM.NLS_STRING_UNITS = 'SYSTEM';

CREATE UNIQUE INDEX "DB2TST  "."U_IDX1_3" ON "DB2TST  "."P1" 
                ("COL1" ASC,"COL3" ASC)
                NOT PARTITIONED IN "TBS2"

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;
 

結論：對於唯一索引，如果索引中包含了分割槽健，預設是分割槽索引。如果索引中不包含分割槽健，預設是非分割槽索引。
問題：如果是不包含分割槽健的唯一索引，想做成分割槽的怎麼破？答：沒有辦法，建立的時候會報錯 SQL20303N

$ db2 "create unique index u_idx3 on p1 (col3) partitioned"
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:

2. 主健

刪表重建 
$ db2 "alter table p1 add primary key(col1)"
$ db2 "select varchar(INDNAME,40) as idxname from syscat.indexpartitions where TABNAME='P1'"

IDXNAME                                 
----------------------------------------

  0 record(s) selected.

$ db2 "alter table p1 drop primary key"
$ db2 "alter table p1 add primary key(col1,col2)"
$ db2 "select varchar(INDNAME,40) as idxname from syscat.indexpartitions where TABNAME='P1'"

IDXNAME                                 
----------------------------------------
SQL200122112144130                      
SQL200122112144130                      
SQL200122112144130                      

  3 record(s) selected.

結論：主健實際上是唯一索引，因此效果跟唯一索引類似，即：
如果主健中包含了分割槽健，則主健對應索引是分割槽索引。 如果主健中不包含分割槽健，則索引是非分割槽索引。

3. 非唯一索引

刪表重建

$ db2 "create index idx1 on p1 (col1)"
$ db2 "create index idx1_2 on p1 (col1,col2)"
$ db2 "create index idx1_3 on p1 (col1,col3)"
$ db2look -d sample -a -e -t p1

CREATE INDEX "DB2TST  "."IDX1" ON "DB2TST  "."P1" 
                ("COL1" ASC)
                PARTITIONED

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;

-- DDL Statements for Indexes on Table "DB2TST  "."P1"

SET SYSIBM.NLS_STRING_UNITS = 'SYSTEM';

CREATE INDEX "DB2TST  "."IDX1_2" ON "DB2TST  "."P1" 
                ("COL1" ASC,"COL2" ASC)
                PARTITIONED

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;

-- DDL Statements for Indexes on Table "DB2TST  "."P1"

SET SYSIBM.NLS_STRING_UNITS = 'SYSTEM';

CREATE INDEX "DB2TST  "."IDX1_3" ON "DB2TST  "."P1" 
                ("COL1" ASC,"COL3" ASC)
                PARTITIONED

                COMPRESS NO 
                INCLUDE NULL KEYS ALLOW REVERSE SCANS;

結論：非唯一索引預設都是分割槽索引。