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HP NonStop Shadowbase Command Definitions

Database Specification Command Descriptions

HP NonStop Shadowbase Command Reference Manual—785421-002

257

Version Version Values Default Minimum Maximum Alter

3.943 5.002 OFF OFF ON No

This parameter is used to define if Enscribe file and SQL/MP table purge

events are to be replicated to the target. By default, this parameter is set

to OFF. Set it to ON to enable the feature.

When a purge event is read from the audit trail and it is to be replicated,

HP Shadowbase will first close the target (assuming it has it open), and

then issue an Enscribe file purge or SQL/MP drop operation accordingly.

In general, the purge event will attempt to remove all base file/table

partitions as well as all alternate key file partitions in the target file

definition. SQL/MP indexes are always dropped along with the base table.

Notes: In version 3.943, DBS parameters were added to filter file

purge and create events to the Consumer’s user exits. However it was up

to the user to add the file create and purge logic to HP Shadowbase via

user exit routines. In v4.060B, this functionality was added to the standard

HP Shadowbase product.

Important Note If you are using bi-directional replication and you have

user exits that process SQL/MP DDL events:

Because file and table partitions may be split across multiple Consumer

processes, HP Shadowbase has been enhanced to coordinate all alter,

create, purge, and purgedata DDL events, such that all Consumer

processes are “drained” of events first, and then the DDL event is sent to

the appropriate Consumer to be processed. After the DDL event has

been processed, non-DDL replication can resume. This coordination is

necessary so that events are processed synchronously in the correct

sequence across multiple Consumer threads.

It is recommended that an AUDCOM SUSPENDUPD be issued before

any DDL sequences that create a base file or table and then subsequently

create alternate key files or indexes. The AUDCOM RESUMEUPD should

be issued after the multi-step sequence is finished. This is necessary to

have HP Shadowbase see the indexes and alternate key files when it

processes the create event so that it can create them for the target file or

table. Otherwise, it is possible that the index and alternate key files don’t

get created.

If you have Enscribe or SQL/MP DDL replication operating in a bi-

directional environment and you have user exits that alter, create,

purge/drop, or purgedata against a target table that may be processed in

the reverse direction, your user exit should be programmed using the

following steps to prevent ping-pong:

1. Call the user exit SBSETDDLNOALTERS API function.

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