Amy Tai b77b47ada8 Enable scheduler to update its jobs list
Previously, the scheduler only populated its jobs list once at start time. This commit enables the scheduler to receive notifications for updates (insert, update, delete) to the bgw_job table. Notifications are sent via the cache invalidation framework. Whenever the scheduler receives a notification, it re-reads the bgw_job table. For each job currently in the bgw_job table, it either instantiates new scheduler state for the job or copies over any existing scheduler state, for persisting jobs. For jobs that have disappeared from the bgw_job table, the scheduler deletes any local state it has.

Note that any updates to the bgw_job table must now go through the C, so that the cache invalidation framework in catalog.c can run. In particular, this commit includes a rudimentary API for interacting with the bgw_job table, for testing purposes. This API will be rewritten in the future.
2018-11-07 15:53:04 -05:00
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2018-09-10 13:29:59 -04:00