This is particularly problematic because of the quoting required to examine hdfs paths with a "!" character in them. The root table ID and the metadata table ID should not use special characters.
- should not collide with possible user table IDs
- might be useful, but may not be necessary, to retain lexicographical sort order, so root table goes first, then metadata table, then other tables
- Use negative numbers: -1 for the root table, -2 for the metadata table (my personal favorite)
- Use a different special character: %, &, +, or . (each of which may have special considerations)
- Reserve a block of IDs for internal use (say, 0-10 or 0-100), and move other tables on upgrade