When entering an external directory group in the TIBCO Spotfire Server LDAP configuration "group-synchronization" settings (TIBCO Spotfire Server Configuration Tool > Configuration Tab > User Directory > Group Synchronization), a NULL group is sometimes entered after the last group. If this configuration is allowed to sync then the TIBCO Spotfire Server may inadvertently fetch all the groups from external directory causing Spotfire to become very slow.
In the configuration.xml, you can see the entry "<name />" at the end as shown in below example:
<group-names>
<name>CN=mygroup1,DC=na,DC=mycomp,DC=com</name>
<name>CN=mygroup2,DC=na,DC=mycomp,DC=com</name>
<name />
</group-names>