brandtg/switchboard — pull request #23 by brandtg (2014-06-05 07:02:23+00:00)
Title: Indexer-generated SCNs (#21)

This enables the indexer to generate SCNs that are monotonically increasing per-database.

To do this, we reserve the high order bits of the SCN value as "generation". Each database has a generation, and generations are monotonically increasing.

Generations are maintained in the `generationInfo` table, per-database.