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HP NonStop Shadowbase Command Definitions

Database Specification Command Descriptions

HP NonStop Shadowbase Command Reference Manual—785421-002

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DELETES { ON }

{ OFF }

Initial Changed

Version Version Values Default Minimum Maximum Alter

2.000 ON OFF ON No

This indicates whether the source database deletes are to be applied to

the target. The default is ON.

Note: When the DELETES parameter is set to OFF, deletes are not

applied to the target, but insert undo events are applied.

DELUIDXDUP { ON }

{ OFF }

Initial Changed

Version Version Values Default Minimum Maximum Alter

3.964B OFF OFF ON No

When the target Consumer is applying an I/O event against a target file or

table with a unique alternate key file or index, it is possible for the base file

I/O to be successful yet the I/O to the alternate key file or index to fail with

a duplicate key error. A simple example illustrates the issue – assume a

uni-directional replication scenario where the target database is not initially

empty and is not synchronized with the source database (this is often

referred to as a “fuzzy replication” scenario):

 Assume the source database table is initially empty, yet the target

database table has a record with primary key value of 1 and a unique

index value of 1. In other words, the two are not initially synchronized

when replication is enabled/started.

 Now assume that a source application inserts a row into the source

table with primary key value of 2 and a unique index value of 1. This

source insert is successful.

 When the replication engine applies that change into the target

database, the base table insert will be successful, yet the unique index

insert will fail with a duplicate key error (which backs out, or undoes,

the entire insert on the target). In the previous versions of HP

Shadowbase, this duplicate key error would be mistakenly viewed as a

duplicate key error on the primary key (not the unique index) and

would cause the INSERT event to be mapped into an UPDATE (if the

fuzzy replication DBS parameter UPDATEDUPLICATE is ON), and re-

applied. Executing this UPDATE will cause a “not found” condition (as

no record with a primary key value of 2 exists in the target table), and

then the UPDATE would be logged and discarded. In other words, the

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