User's Manual

♦ Keep the number of publications small In particular, try not to
reference the same table in many different publications.
The work the database server needs to do is proportional to the number of
publications. Keeping the number low and making effective use of
subscriptions lightens the load on the database server.
When operations occur on a table, the database server and the Message
Agent must do some work for each publication that contains the table.
Having one publication for each remote user will drastically increase the
load on the database server. It is much better to have a few publications
that use SUBSCRIBE BY and have subscriptions for each remote user.
The database server does no additional work when more subscriptions are
added for a publication. The Message Agent is designed to work
efficiently with a large number of subscriptions.
♦ Group publications logically For example, if there is a table that every
remote user requires, such as a price list table, make a separate
publication for that table. Make one publication for each table where the
data can be partitioned by a column value.
♦ Use subscriptions effectively When remote users receive similar
subsets of the consolidated database, always use publications that
incorporate SUBSCRIBE BY expressions. Do not create a separate
publication for each remote user.
♦ Pay attention to Update Publication Triggers In particular:
• Use the NEW / OLD SUBSCRIBE BY syntax.
• Tune the SELECT statements to ensure they are accessing the database
efficiently.
♦ Monitor the transaction log size The larger the transaction log, the
longer it takes the Message Agent to scan it. Rename the log regularly
and use the DELETE_OLD_LOGS option.
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