91b752dce6
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.
84 lines
2.1 KiB
Ruby
84 lines
2.1 KiB
Ruby
require 'spec_helper'
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describe BackgroundMigrationWorker, :sidekiq, :clean_gitlab_redis_shared_state do
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let(:worker) { described_class.new }
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describe '.minimum_interval' do
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it 'returns 2 minutes' do
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expect(described_class.minimum_interval).to eq(2.minutes.to_i)
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end
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end
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describe '.perform' do
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it 'performs a background migration' do
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expect(Gitlab::BackgroundMigration)
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.to receive(:perform)
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.with('Foo', [10, 20])
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worker.perform('Foo', [10, 20])
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end
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it 'reschedules a migration if it was performed recently' do
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expect(worker)
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.to receive(:always_perform?)
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.and_return(false)
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worker.lease_for('Foo').try_obtain
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expect(Gitlab::BackgroundMigration)
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.not_to receive(:perform)
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expect(described_class)
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.to receive(:perform_in)
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.with(a_kind_of(Numeric), 'Foo', [10, 20])
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worker.perform('Foo', [10, 20])
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end
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it 'reschedules a migration if the database is not healthy' do
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allow(worker)
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.to receive(:always_perform?)
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.and_return(false)
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allow(worker)
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.to receive(:healthy_database?)
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.and_return(false)
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expect(described_class)
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.to receive(:perform_in)
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.with(a_kind_of(Numeric), 'Foo', [10, 20])
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worker.perform('Foo', [10, 20])
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end
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end
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describe '#healthy_database?' do
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context 'using MySQL', :mysql do
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it 'returns true' do
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expect(worker.healthy_database?).to eq(true)
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end
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end
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context 'using PostgreSQL', :postgresql do
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context 'when replication lag is too great' do
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it 'returns false' do
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allow(Postgresql::ReplicationSlot)
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.to receive(:lag_too_great?)
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.and_return(true)
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expect(worker.healthy_database?).to eq(false)
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end
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end
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context 'when replication lag is small enough' do
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it 'returns true' do
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allow(Postgresql::ReplicationSlot)
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.to receive(:lag_too_great?)
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.and_return(false)
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expect(worker.healthy_database?).to eq(true)
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end
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end
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end
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end
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end
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