Problem creating index table

Question

I am having a strange problem with an indexed table. I am using the Oracle 11g standard.

I have a src_table

SQL> desc src_table;
 Name            Null?    Type
 --------------- -------- ----------------------------
 ID     NOT NULL   NUMBER(16)
 HASH       NOT NULL   NUMBER(3)
 ........

SQL> select count(*) from src_table;
  COUNT(*)
----------
  21108244

now create another table and copy 2 columns from src_table

set timing on
SQL> create table dest_table(id number(16), hash number(20), type number(1));
Table created.
Elapsed: 00:00:00.01

SQL> insert /*+ APPEND */ into dest_table (id,hash,type) select id, hash, 1 from src_table;
21108244 rows created.
Elapsed: 00:00:15.25

SQL> ALTER TABLE dest_table ADD ( CONSTRAINT dest_table_pk PRIMARY KEY (HASH, id, TYPE));
Table altered.
Elapsed: 00:01:17.35

Oracle required <2 min.

now same exercise but with IOT table

SQL> CREATE TABLE dest_table_iot (
       id     NUMBER(16) NOT NULL,
       hash  NUMBER(20) NOT NULL,
       type  NUMBER(1)  NOT NULL,
       CONSTRAINT dest_table_iot_PK PRIMARY KEY (HASH, id, TYPE)
    ) ORGANIZATION INDEX;

Table created.
Elapsed: 00:00:00.03

SQL> INSERT /*+ APPEND */ INTO dest_table_iot (HASH,id,TYPE)
    SELECT  HASH, id, 1 
    FROM src_table; 

"insert" in IOT takes 18 hours !!! I tried this on two different Oracle instances running on win and linux and got the same results.

What's going on here? Why is it taking so long?

Answer 1

The APPEND tip is only useful for heap-organized tables.

IOT, , ​​ , .

, , , , .

, , APPEND, 18 .

ORDER BY SELECT , IOT. - , .