# Performance Implications of Monitor Topics

The TIBCO Enterprise Message Service server only generates messages for monitor topics that currently have subscribers. So, if no applications subscribe to monitor topics, no monitor messages are generated. Generating a monitor message does consume system resources, and therefore you should consider what kinds of monitoring your environment requires. System performance is affected by the number of subscribers for monitor topics as well as the frequency of messages for those topics.

For development and testing systems, monitoring all system events is probably desirable. Usually, development and testing systems do not have large message volumes, and monitoring can give you information about system problems.

For production systems, monitoring all events may have an adverse effect on system performance. Therefore, you should not create topic subscribers for `$sys.monitor.>` in your production system. Also, monitor events are likely to be added in future releases, so the number of monitor topics may grow. Subscriptions to monitor topics in production systems should always be limited to specific monitor topics or wildcard subscriptions to specific classes of monitor topics that are required.

Also, consider the frequency of messages to each monitor topic. System administration events, such as creating topics, routes, and changing permissions, do not occur frequently, so creating subscriptions for these types of events will most likely not have a significant effect on performance.

Also, using message selectors to limit monitor messages can improve performance slightly. The server does not send any messages that do not match a subscriber’s message selector. Even though the message is not sent, the message is still generated. Therefore there is still system overhead for subscribers to a monitor topic, even if all messages for that topic do not match any subscriber’s message selector filter.

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