DataHandler::clear_cache() does not consider workspaces
DataHandler::clear_cache() is called with a table and a uid that has been modified to trigger the clear cache commands. To find siblings, children, parents, etc. the pid value is directly used to find the affected pages. However, in a workspace context, the pid is always "-1" which leads to a selection of all page records of all workspaces. This amount is used to flush all defined caches by a given tag name and might result in execution time outs.