Question

I have table with huge data and which is in production at client side. I have to do online partitionig of it means I can halt the production and the table should be partitioned. I have got the script to do it. But I dont know how to do it online. Is their any way by which I can achieve this. Please suggest..

Answer 1

Follow the below steps,

1. Create temporary table in the same structure as the main table (for example TABLE_P for TABLE) and partition this temporary table on the required column. Don’t add primary keys and other indexes of the main table to this temporary table.

   create table TABLE_P
       (
         COL1        VARCHAR2(35 CHAR) not null,
         COL2        VARCHAR2(35 CHAR) not null,
       )
       --add partition (Example taken here is Range partitioning)  from here
        PARTITION BY RANGE (COL1) (
        PARTITION p0 VALUES LESS THAN (5),
        PARTITION p1 VALUES LESS THAN (10),
        PARTITION p2 VALUES LESS THAN (15),
        PARTITION p3 VALUES LESS THAN (MAXVALUE)
       --add partition till here
   

2. Create an index to this table with the required column.

   create index IX01_TABLE on TABLE_P (COL1) local;         
   

3. Run the below scripts for redifinition. Replace with the actual schema name.

   begin
   dbms_redefinition.can_redef_table( 'SCHEMA', 'TABLE' );
   end;
   /
   
   begin
   dbms_redefinition.start_redef_table('SCHEMA', 'TABLE','TABLE_P' );
   end;
   /
   
   declare
     error_count pls_integer := 0;
   BEGIN
     dbms_redefinition.copy_table_dependents(uname      => 'SCHEMA',
                                             orig_table => 'TABLE',
                                             int_table  => 'TABLE_P',
                                             num_errors => error_count);
     dbms_output.put_line('errors := ' || to_char(error_count));
   END;
   /
   
   begin
   dbms_redefinition.finish_redef_table('SCHEMA', 'TABLE','TABLE_P');
   end;
   /
   

Note that this will make the dependant objects to go INVALID in the schema, so be prepared for some downtime to clear these invalids.