For performance and efficiency reasons Tigase heavily relies on data stored in memory, it keeps many local caches in components and other parts of the system. This is especially significant in cluster mode. So, the best/safest way to restore DB dump is to stop Tigase, restore DB and then start Tigase again.

I guess, in some very specific circumstances, when there is no significant differences between data being restored and the data already in DB you might do this while Tigase is running without restart. For example, if you restore data for offline users. But this is really case-by-case exception to the general rule above.

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