What limitations exist on identifier indexes?
Assuming the underlying computer operating system and hardware have the capacity, index files produced by xdformat are currently limited to 8 TB (8,192 GB) in size, a limit that can be readily increased to 256 TB in the program if necessary. With its current configuration, however, an index of 50+ million entries requires less than 3 GB storage; and because storage requirements for the index increase only marginally faster than linearly with the number of entries, the current limit seems likely to suffice for some time. If the size of an index is problematic, or if faster retrieval is required, indexing can be restricted to the most important classes of identifiers using the T option.
