2 ms·

So it can’t use the internal id index, result: slow lookups for external ids.

• bfung 2y ago
  > secondary indices on the external_id columns in both tables pick your poison, slower lookup or more disk usage
  • masklinn 2y ago
    There are other fun ideas to explore e.g. if your external id is a hash you can rebuild, it might be an option to scavenge the full hash but keep the first few bytes of it, indexed. That increases lookup costs if the hash does not exist or has been scavenged but lowers storage. In fact if your external ids are evenly distributed you can do that anyway, only index the few leading / trailing bytes of the id. That will increase lookup costs a bit but significantly decrease storage.