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SQL Anywhere 10.0.1 » SQL Remote » Deploying and Synchronizing Databases with SQL Remote » Using the Extraction utility (dbxtract)

Using the Extraction utility from Sybase Central Next Page

Designing an efficient extraction procedure

It is very inefficient to create a large number of remote databases by running the Extraction utility for each one. You can make the process much more efficient. This section describes one way of making the process more efficient.

There are several potential causes of inefficiency in a large-scale extraction process:

An efficient approach to extracting many databases

One approach that avoids these problems is as follows:

  1. Make a copy of the consolidated database, and at the same time start the subscriptions from the live database. Messages will now start being sent to subscribers, even though they have no database and will not receive them yet.

    To start several subscriptions within a single transaction, use the REMOTE RESET statement.

  2. Extract the remote databases from the copy of the database. As the database is a copy, there are no locking and concurrency problems. For a large number of remote databases, this process may take several days.

  3. As each remote database is created, it is out of date, but its user can receive and apply messages that have been being sent from the live consolidated database, to bring themselves up to date.

This solution interferes with the production database only during the first step. The copy must be made at isolation level three if the database is in use, and uses large numbers of locks. Also, the subscriptions must be started at the same time that the copy is made. Any operations that take place between the copy and the starting of the subscriptions would be lost, and could lead to errors at remote databases.