We have discovered that adding an index to the ALOGIN table can potentially help with performance where the ALOGIN table gets very large, for example around 100'000 records.  We noted a definate improvement for SOAP Web Service calls, but may also help if you are seeing "ghost" sessions once all users have logged out.

R&D have been alerted so will be revised in future versions, but if you have such a situation on your Sage X3 system right now, feel free to add an index on fields ADOID+FLG for table ALOGIN.  This applies to V12, V11 and U9 versions.

You can add this index in the "Database Optimisation" (GESANX) function