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ORA-01450: Maximum Key Length (6398) Exceeded

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  • User AvatarKiran Dalvi
  • 07 Dec, 2023
  • 0 Comments
  • 49 Secs Read

ORA-01450: Maximum Key Length (6398) Exceeded

Problem :

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SQL> create index EMP_TAB_IDX1 on EMP_TAB ( EMPNAME,LOCATION,DEPT);
create index EMP_TAB_IDX1 on EMP_TAB ( EMPNAME,LOCATION,DEPT)
*
ERROR at line 1:
ORA-01450: maximum key length (6398) exceeded

Solution :

For a database with block size of 8K , Index length can be maximum of 6398. Lets describe the table
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SQL> desc EMP_TAB
Name Null? Type
----------------------------------------- -------- -------------------
EMPNO NUMBER
EMPNAME VARCHAR2(3000)
LOCATION VARCHAR2(3000)
DEPT VARCHAR2(2000)
Here we are trying to create composite index on empname varchar2(3000) , location varchar2(3000) , dept varchar2(2000). If we add the length 3000+3000+2000=9000 > 6398 . It is greater than the allowed value. So to avoid this error, either we have to create the index with length less than 6398 . Else we can create a tablespace with higher block size value( like 16k/32k) and create the index in that tablespace .
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SQL> create index EMP_TAB_IDX1 on EMP_TAB ( EMPNAME,LOCATION);
Index created.
Above index creation worked, because 3000 + 3000 < 6398 .

Hope it Helps!