Thursday, 15 May 2014

OGG - PASSTHRU/NOPASSTHRU



PASSTHRU - NOPASSTHRU

You can specify the PASSTHRU parameter on the data pump if you aren’t doing any filtering or column mapping and your source and target data structures are identical. For GoldenGate to consider the tables identical, they must have the same column names, data types, sizes, and semantics and appear in the same order. Using PASSTHRU improves performance by allowing GoldenGate to bypass looking up any table definitions from the database or the data-definitions file.

The PASSTHRU and NOPASSTHRU parameters are TABLE-specific. One parameter remains in effect for all subsequent TABLE statements, until the other parameter is encountered. This enables you to specify pass-through behavior for one set of tables while using normal processing, including data filtering and other manipulation, for other tables.

Example

The following parameter file configures pass-through mode for all data from fin.acct, but allows normal processing for fin.sales.

EXTRACT fin
USERIDALIAS tiger1
RMTHOST sysb, MGRPORT 7809, ENCRYPT AES192 KEYNAME mykey
ENCRYPTTRAIL AES192
RMTTRAIL /ggs/dirdat/rt
PASSTHRU
TABLE fin.acct;
NOPASSTHRU
TABLE fin.sales, WHERE (ACCOUNT-CODE < 100);

In PASSTHRU mode, the data pump will not perform automatic ASCII-to-EBCDIC or EBCDIC-to-ASCII conversion.

PASSTHRU in DDL Replication

DDL is propagated by a data pump in PASSTHRU mode automatically. As a result, DDL that is performed on a source table of a certain name (for example ALTER TABLE TableA...) is processed by the data pump using the same name (ALTER TABLE TableA). The name cannot be mapped by the data pump as ALTER TABLE TableB, regardless of any TABLE statements that specify otherwise.

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