text: IF EXISTS (SELECT name FROM sys.indexes
      WHERE name = N'ProcessedOutboxMessagesNonClusteredIndex'
      AND object_id = OBJECT_ID (N'dbo.OutboxMessages'))
  DROP INDEX ProcessedOutboxMessagesNonClusteredIndex
      ON OutboxMessages
  GO
  
  CREATE NONCLUSTERED INDEX ProcessedOutboxMessagesNonClusteredIndex
      ON dbo.OutboxMessages ([CreationDate] ASC, [Category]) INCLUDE ([Id], [Data], [Type], [ProcessedDate])
      WHERE ProcessedDate IS NULL;
  GO