Briefly, Deskzilla can slow down Bugzilla if Bugzilla server is slow. Deskzilla gives the users more power than the web interface, which leads to more requests to the server.
In detail, all Deskzilla requests to Bugzilla fall down into the following categories:
- Configuration sync - this is the most stressful operation, when Deskzilla sends many requests to the server to download all possible values and configuration and sample bugs. It happens when a) a new connection to the server is configured in Deskzilla; b) when a user selects menu Connection | Reload Bugzilla Configuration; c) automatically once every 12 hours - unless connection's "Get Changes in Background" flag is OFF.
- Query download - when a query is run for the first time, Deskzilla needs to get bugs from the server. After the query has been executed once, Deskzilla will display the result instantly without going to the server. The initial download can be stressful if it involves getting a large number of bugs.
- Regular synchronization - once every 2-3 minutes Deskzilla checks if any bugs have been changed on the server. This is a simple request that searches for all bugs with updated time >X. Typically it runs very fast but if there are many users running Deskzilla at the same time they could put some load on the server. Additionally, if your Bugzilla database is tweaked somehow (for example, not having an index on updated time), it could slow down database significantly.
- Upload - happens quite rarely when the user changes something and uploads. Since Deskzilla repeats what the user would do on the web interface, this is unlikely to cause performance problems. However, if the user changes lots of bugs and then uploads all the changes at once, there will be a constant stream of upload actions (but not more than one upload action at a time from a single Deskzilla).