User's Manual

Chapter 9. Deploying and Synchronizing Databases
Synchronizing databases
What is synchronization? SQL Remote replication is carried out using the information in the
transaction log, but there are two circumstances where SQL Remote deletes
all existing rows from those tables of a remote database that form part of a
publication, and copies the publication’s entire contents from the
consolidated database to the remote site. This process is called
synchronization.
When to synchronize Synchronization is used under the following circumstances:
♦ When a subscription is created at a consolidated database a
synchronization is carried out, so that the remote database starts off with
a database in the same state as the consolidated database.
♦ If a remote database gets corrupt or gets out of step with the consolidated
database, and cannot be repaired using SQL passthrough mode,
synchronization forces the remote site database back in step with the
consolidated site.
How to synchronize Synchronizing a remote database can be done in the following ways:
♦ Use the database extraction utility This utility creates a schema for a
remote Adaptive Server Anywhere database, and synchronizes the remote
database. This is generally the recommended procedure.
♦ Manual synchronization Synchronize the remote database manually by
loading from files, using the PowerBuilder pipeline, or some other tool.
♦ Synchronize over the message system Synchronize the remote
database via the message system using the SYNCHRONIZE
SUBSCRIPTION statement (Adaptive Server Anywhere ) or
sp_subscription ’synchronize’ procedure (Adaptive Server Enterprise).
Caution
Do not execute SYNCHRONIZE SUBSCRIPTION or sp_subscription
’ synchronize ’ at a remote database.
Mixed operating systems and database extraction
In many installations, the consolidated server will be running on a different
operating system than the remote databases.
Adaptive Server Anywhere databases can be copied from one file or
operating system to another. This allows you flexibility in how you carry out
your initial synchronization of databases.
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