Oracle EXCHANGE PARTITION tips Oracle Tips by Burleson Consulting

Oracle EXCHANGE PARTITION

One of the most time-consuming processes in any data warehouse is the creation of the Extract, Transformation and Load (ETL) processes.  One of the best features in Oracle data warehousing is the ability to swap-out standard Oracle tables and partitioned tables.

Here is the syntax of the EXCHANGE PARTITION command:

ALTER TABLE <table_name>

EXCHANGE PARTITION <partition_name>

WITH TABLE <new_table_name>

<including | excluding> INDEXES

<with | without> VALIDATION

EXCEPTIONS INTO <schema.table_name>;

In Oracle Data Warehouse ETL, the incoming data is loaded into a “staging” table, using Oracle Data Pump or SQL*Loader, normally with:

• Deferred index building

• Adding rows into new freelist blocks (the APPEND clause)

• Using direct-path loading (nologging, unrecoverable)

Preparing a new table partition is resource-intensive.  Loading the new data into a staging area relieves any concurrent-user issues, because the staging table is segregated from the “live” data warehouse.

Once the data is loaded into the staging table you can build the indexes, estimate the CBO statistics, and use the “exchange partition” command to load the table into the production environment with minimal impact.

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