52 lines
		
	
	
	
		
			1.9 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
			
		
		
	
	
			52 lines
		
	
	
	
		
			1.9 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
| class CopyAccountStats < ActiveRecord::Migration[5.2]
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|   disable_ddl_transaction!
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| 
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|   def up
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|     safety_assured do
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|       if supports_upsert?
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|         up_fast
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|       else
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|         up_slow
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|       end
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|     end
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|   end
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| 
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|   def down
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|     # Nothing
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|   end
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| 
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|   private
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| 
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|   def supports_upsert?
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|     version = select_one("SELECT current_setting('server_version_num') AS v")['v'].to_i
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|     version >= 90_500
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|   end
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| 
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|   def up_fast
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|     say 'Upsert is available, importing counters using the fast method'
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| 
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|     Account.unscoped.select('id').find_in_batches(batch_size: 5_000) do |accounts|
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|       execute <<-SQL.squish
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|         INSERT INTO account_stats (account_id, statuses_count, following_count, followers_count, created_at, updated_at)
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|         SELECT id, statuses_count, following_count, followers_count, created_at, updated_at
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|         FROM accounts
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|         WHERE id IN (#{accounts.map(&:id).join(', ')})
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|         ON CONFLICT (account_id) DO UPDATE
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|         SET statuses_count = EXCLUDED.statuses_count, following_count = EXCLUDED.following_count, followers_count = EXCLUDED.followers_count
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|       SQL
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|     end
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|   end
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| 
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|   def up_slow
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|     say 'Upsert is not available in PostgreSQL below 9.5, falling back to slow import of counters'
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| 
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|     # We cannot use bulk INSERT or overarching transactions here because of possible
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|     # uniqueness violations that we need to skip over
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|     Account.unscoped.select('id, statuses_count, following_count, followers_count, created_at, updated_at').find_each do |account|
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|       params = [[nil, account.id], [nil, account[:statuses_count]], [nil, account[:following_count]], [nil, account[:followers_count]], [nil, account.created_at], [nil, account.updated_at]]
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|       exec_insert('INSERT INTO account_stats (account_id, statuses_count, following_count, followers_count, created_at, updated_at) VALUES ($1, $2, $3, $4, $5, $6)', nil, params)
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|     rescue ActiveRecord::RecordNotUnique
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|       next
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|     end
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|   end
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| end
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