1. 06 Aug, 2018 1 commit
    • Yorick Peterse's avatar
      Respond to DB health in background migrations · 91b752dc
      Yorick Peterse authored
      This changes the BackgroundMigration worker so it checks for the health
      of the DB before performing a background migration. This in turn allows
      us to reduce the minimum interval, without having to worry about blowing
      things up if we schedule too many migrations.
      
      In this setup, the BackgroundMigration worker will reschedule jobs as
      long as the database is considered to be in an unhealthy state. Once the
      database has recovered, the migration can be performed.
      
      To determine if the database is in a healthy state, we look at the
      replication lag of any replication slots defined on the primary. If the
      lag is deemed to great (100 MB by default) for too many slots, the
      migration is rescheduled for a later point in time.
      
      The health checking code is hidden behind a feature flag, allowing us to
      disable it if necessary.
      91b752dc
  2. 01 Aug, 2018 32 commits
  3. 31 Jul, 2018 7 commits