HSQLDB Limitation/Question


I’m currently testing Openfire with embedded HSQLDB and I did not find what the the "

Maximum Connections" in the section “Connection Pool Info” means, is there a limit to 25 concurent users with the embedded DB ?



There is no limitation to the number of users with the embedded database until you get really high in numbers. The embedded database has other shortcomings that are more important (backups, editing, performance under load). MySQL or some other separate database would be better.

Hi mtstravel,

Thanks for the very fast answer, I plan to use Openfire in our small (100 users) network, I guess in terms of performances the HSQLDB should be OK. We have Oracle servers around but I do not want to bother my dba if I can live with the embedded DB,. About backups I was precisely looking at that and could not find a procedure. I don’t mind shutting down the DB or Openfire at nights for backups, can you tell me what I should save (because the directory “embedded-db” does not contains files that are looking like a db only a .lck file) ?

Thanks again


I backed up the entire openfire directory, when I used the embedded db. I only ran on this for about a year until I had an issue that required editting the db. This proved to be near impossible with the embedded db. I strongly recommend using MySQL. It is free, can run on the same server as Openfire, and can be configured to autobackup the openfire db on a schedule.


I trust you. I’ll do that.

Thanks again


Hi Patrick,

I don’t to step on mtstravel’s toes or speak ill of MySQL but if your organization already has the infrastructure (including backups, security, hardware, etc.) in place to support deploying Openfire using Oracle that might be a better way to go. I know dba’s are often times pretty busy but it might be worth the little bit of time and effort to get them involved now rather down the road.



I would fully agree with this course of action if it is possible. I assumed not due to your previous message. But if it is this is the best choice.


If I go with Oracle my dba will ask me some figures about db sizing. Do you have some data for a small network like mine (100 users) ?



That could range greatly depending on your configuration. With such a small user base the db could be small. If you enable more plugins and features it will grow rapidly. I will give you a more precise answer when I get access to mine later today.

My database in MySQL with about 200 users is around 1MB. I do not use chat logging, so that keeps the size low, and my system is LDAP. I do have avatars enabled but very few people use them.

Thank you,

It’s now in my dba hands…

Have a nice day