Chapter 10. SQL Remote Administration
Encoding and compressing messages
Asmessages pass through e-mail and other message systems, there is a
dangerof them becoming corrupted. Forexample, some message systems
usecertain characters or character combinations as control characters.
Messagesize affects the efficiency with which messages pass through a
system. Compressed messages can be processed more efficiently by a
messagesystem than uncompressed messages. Onthe other hand, carrying
outcompression can itself take a significant amount of time.
SQLRemote encoding
andcompression SQLRemote has a message encoding and compression scheme built in to
theMessage Agent. Thescheme provides the following features:
Compatibility Thesystem can be set up to be compatible with previous
versionsof the software.
Compression Youcan select a level of compression for your messages.
Encoding SQLRemote encodes messages to ensure that they pass
throughmessage systems uncorrupted. Theencoding scheme can be
customizedto provideextra features.
Settingsfor compatibility Tobe compatible with previous versions of the software, you should set the
databaseoption COMPRESSION to be -1 (minus one) at each database
runningthe Version 6 software. This setting ensures that messages are sent
outin a format compatible with older versions of the software.
UpgradingSQL Remote If you upgrade the consolidated database Message Agent first, you should
setits COMPRESSION database option to -1. Aseach remote site in your
replicationsystem is upgraded to Version 6, you can change its setting of the
COMPRESSIONoption to a value between 0 (no compression) and 9
(maximumcompression). Thisallows you to take advantage of compression
featureson messages being sent to the consolidated database. Onceall
remotesites are upgraded, you can set the consolidated site Message Agent
COMPRESSIONoption to a value other than -1.
Inaddition, setting COMPRESSION to a value other than -1 allows you to
takeadvantage of the Version 6 message encoding improvements.

The encoding scheme

Thedefault message-encoding behavior of SQL Remote is as follows:
Formessage systems that can use binary message formats, no encoding is
carriedout.
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