Current Tealeaf versions are restricted to defining 256 dimensions. The limit is applied via validation logic in this file: \Portal\Webapp\JS\tlevents.js

There is no architectural reason for the current limit... it's a holdover from when the 8.x data model was experimental. The costs associated with Dimensions and Fact Data are related to how they are used, and not by the total number of dimensions.

Changing the limit from 256 to 1024 is safe and has been deployed at several customer sites and cxOverstat POCs, when the addition of Overstat dimensions would exceed the limit. To lift the limit via a manual adjustment (in \Portal\Webapp\JS\tlevents.js):

addDimension : function(postMethod, type, itemname)
{
var dimCount = TLEventsObj.getDimensionCount();
if (dimCount >= 256 ) {
TLEventsObj.modalError(LocalStrings.ERROR_EXCEEDED_MAX_DIMS);
return;
}

The enhancement request is to raise the default limit and make the limit configurable, so that a change in the tlevents.js file will not be lost upon upgrade.