Handling Read Requests in BigCouch

BigCouch_read_request_handling.md

Handling Read Requests in BigCouch

• R=1, D=1, S=1: V

• R=2, D=1, S=1:

  • V
  • 503 Service Unavailable

• R=2, D=1, S=2: V

• R=2, D=2, S=2:

  • max(V)
  • [V₁, V₂]
  • 503 Service Unavailable

• R=3, D=1, S=1:

  • V
  • 503 Service Unavailable

• R=3, D=1, S=2:

  • V
  • 503 Service Unavailable

• R=3, D=1, S=3: V

• R=3, D=2, S=2:

  • max(V)
  • [V₁, V₂]
  • 503 Service Unavailable

• R=3, D=2, S=3:

  • quorum(V)
  • max(V)
  • [V₁, V₂, V₃]
  • 503 Service Unavailable

• R=3, D=3, S=3:

  • max(V)
  • [V₁, V₂, V₃]
  • 503 Service Unavailable

Glossary

• V: the set V₁, ..., V_D of document versions returned from the cluster nodes
• S: the number of successful responses (i.e. a document version is available)
• D: number of different versions (i.e. |V|)