Module: PG::Replication::PGOutput

Defined in:
lib/pg/replication/pg_output.rb

Constant Summary collapse

Begin = 
Data.define(:final_lsn, :timestamp, :xid)
Message = 
Data.define(:transactional, :lsn, :prefix, :content)
Commit = 
Data.define(:lsn, :end_lsn, :timestamp)
Origin = 
Data.define(:commit_lsn, :name)
Relation = 
Data.define(:oid, :namespace, :name, :replica_identity, :columns)
Type = 
Data.define(:oid, :namespace, :name)
Insert = 
Data.define(:oid, :new)
Update = 
Data.define(:oid, :key, :old, :new)
Delete = 
Data.define(:oid, :key, :old)
Truncate = 
Data.define(:oid)
Tuple = 
Data.define(:type, :data) do
  def text?
    type == "t"
  end

  def binary?
    type == "b"
  end

  def toast?
    type == "u"
  end
end
Column = 
Data.define(:flags, :name, :oid, :modifier) do
  def key?
    flags == 1
  end
end

Class Method Summary collapse

Class Method Details

.read_message(buffer) ⇒ Object 



35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
 
# File 'lib/pg/replication/pg_output.rb', line 35

def self.read_message(buffer)
  case buffer.read_char
  in "B"
    PGOutput::Begin.new(
      final_lsn: buffer.read_int64,
      timestamp: buffer.read_timestamp,
      xid: buffer.read_int32,
    )

  in "M"
    PGOutput::Message.new(
      transactional: buffer.read_bool,
      lsn: buffer.read_int64,
      prefix: buffer.read_cstring,
      content: case buffer.read_int32
        in 0
          nil
        in n
          buffer.read(n)
      end,
    )

  in "C"
    buffer.read_int8 # Unused byte
    PGOutput::Commit.new(
      lsn: buffer.read_int64,
      end_lsn: buffer.read_int64,
      timestamp: buffer.read_timestamp,
    )

  in "O"
    PGOutput::Origin.new(
      commit_lsn: buffer.read_int64,
      name: buffer.read_cstring,
    )

  in "R"
    PGOutput::Relation.new(
      oid: buffer.read_int32,
      namespace: buffer.read_cstring.then { |ns| ns == "" ? "pg_catalog" : ns },
      name: buffer.read_cstring,
      replica_identity: buffer.read_char,
      columns: buffer.read_int16.times.map do
        PGOutput::Column.new(
          flags: buffer.read_int8,
          name: buffer.read_cstring,
          oid: buffer.read_int32,
          modifier: buffer.read_int32,
        )
      end
    )

  in "Y"
    PGOutput::Type.new(
      oid: buffer.read_int32,
      namespace: buffer.read_cstring,
      name: buffer.read_cstring,
    )

  in "I"
    PGOutput::Insert.new(
      oid: buffer.read_int32,
      new: case a = buffer.read_char
        when "N"
          PGOutput.read_tuples(buffer)
        else
          []
        end,
    )

  in "U"
    oid = buffer.read_int32
    key = []
    new = []
    old = []

    until buffer.eof?
      case buffer.read_char
      when "K"
        key = PGOutput.read_tuples(buffer)
      when "N"
        new = PGOutput.read_tuples(buffer)
      when "O"
        old = PGOutput.read_tuples(buffer)
      end
    end

    PGOutput::Update.new(
      oid:,
      key:,
      old:,
      new:,
    )

  in "D"
    oid = buffer.read_int32
    key = []
    old = []

    until buffer.eof?
      case buffer.read_char
      when "K"
        key = PGOutput.read_tuples(buffer)
      when "O"
        old = PGOutput.read_tuples(buffer)
      end
    end

    PGOutput::Delete.new(
      oid:,
      key:,
      old:,
    )

  in "T"
    PGOutput::Truncate.new(
      oid: buffer.read_int32,
      data: buffer.buffer,
    )

  in unknown
    raise "Unknown PGOutput message type: #{unknown}"
  end
end

.read_tuple(buffer) ⇒ Object 



164
165
166
167
168
169
170
171
172
173
174
175
 
# File 'lib/pg/replication/pg_output.rb', line 164

def self.read_tuple(buffer)
  case (type = buffer.read_char)
  in "n"
    Tuple.new(type:, data: nil)
  in "u"
    Tuple.new(type:, data: nil)
  in type
    size = buffer.read_int32
    data = buffer.read(size)
    Tuple.new(type:, data:)
  end
end

.read_tuples(buffer) ⇒ Object 



160
161
162
 
# File 'lib/pg/replication/pg_output.rb', line 160

def self.read_tuples(buffer)
  buffer.read_int16.times.map { read_tuple(buffer) }
end