Estimate the index size before creating the INDEX

explain plan for

2 create index myapp.order_record_idx01 on myapp.order_record (ORDER_ID,ITEM_NAME)

3 tablespace APPDATA;

 

 

Explained.

 

 

SQL> select * from table(dbms_xplan.display);

 

PLAN_TABLE_OUTPUT

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Plan hash value: 3190873030

 

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| Id  | Operation              | Name               | Rows  | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |

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|   0 | CREATE INDEX STATEMENT |                    |    11M|   197M| 22802   (1)| 00:00:01 |       |       |

|   1 |  INDEX BUILD NON UNIQUE| ORDER_RECORD_IDX01 |       |       |            |          |       |       |

|   2 |   SORT CREATE INDEX    |                    |    11M|   197M|            |          |       |       |

|   3 |    PARTITION RANGE ALL |                    |    11M|   197M| 14956   (2)| 00:00:01 |     1 |     6 |

|   4 |     TABLE ACCESS FULL  | ORDER_RECORD       |    11M|   197M| 14956   (2)| 00:00:01 |     1 |     6 |

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Note

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   - estimated index size: 377M bytes

 

15 rows selected.

 

 

 

 Note: The index size is just estimation, size may vary based on table statistics.