protocol.sgml

PostgreSQL7.4.6 for Linux

This section describes the detailed format of each message.  Each is marked to
indicate that it may be sent by a frontend (F), a backend (B), or both
(F & B).
Notice that although each message includes a byte count at the beginning,
the message format is defined so that the message end can be found without
reference to the byte count.  This aids validity checking.  (The CopyData
message is an exception, because it forms part of a data stream; the contents
of any individual CopyData message may not be interpretable on their own.)
</para>

<VariableList>


<VarListEntry>
<Term>
AuthenticationOk (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(8)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(0)
</Term>
<ListItem>
<Para>
                Specifies that the authentication was successful.
</Para>
</ListItem>
</VarListEntry>
</VariableList>

</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationKerberosV4 (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(8)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(1)
</Term>
<ListItem>
<Para>
                Specifies that Kerberos V4 authentication is required.
</Para>
</ListItem>
</VarListEntry>
</VariableList>
</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationKerberosV5 (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(8)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(2)
</Term>
<ListItem>
<Para>
                Specifies that Kerberos V5 authentication is required.
</Para>
</ListItem>
</VarListEntry>
</VariableList>
</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationCleartextPassword (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(8)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(3)
</Term>
<ListItem>
<Para>
                Specifies that a clear-text password is required.
</Para>
</ListItem>
</VarListEntry>
</VariableList>
</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationCryptPassword (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(10)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(4)
</Term>
<ListItem>
<Para>
                Specifies that a crypt()-encrypted password is required.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Byte2
</Term>
<ListItem>
<Para>
                The salt to use when encrypting the password.
</Para>
</ListItem>
</VarListEntry>
</VariableList>

</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationMD5Password (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(12)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(5)
</Term>
<ListItem>
<Para>
                Specifies that an MD5-encrypted password is required.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Byte4
</Term>
<ListItem>
<Para>
                The salt to use when encrypting the password.
</Para>
</ListItem>
</VarListEntry>
</VariableList>

</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
AuthenticationSCMCredential (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('R')
</Term>
<ListItem>
<Para>
                Identifies the message as an authentication request.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(8)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(6)
</Term>
<ListItem>
<Para>
                Specifies that an SCM credentials message is required.
</Para>
</ListItem>
</VarListEntry>
</VariableList>

</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
BackendKeyData (B)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('K')
</Term>
<ListItem>
<Para>
                Identifies the message as cancellation key data.
                The frontend must save these values if it wishes to be
                able to issue CancelRequest messages later.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32(12)
</Term>
<ListItem>
<Para>
                Length of message contents in bytes, including self.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32
</Term>
<ListItem>
<Para>
                The process ID of this backend.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32
</Term>
<ListItem>
<Para>
                The secret key of this backend.
</Para>
</ListItem>
</VarListEntry>
</VariableList>

</Para>
</ListItem>
</VarListEntry>


<VarListEntry>
<Term>
Bind (F)
</Term>
<ListItem>
<Para>

<VariableList>
<VarListEntry>
<Term>
        Byte1('B')
</Term>
<ListItem>
<Para>
                Identifies the message as a Bind command.
</Para>
</ListItem>
</VarListEntry>
<VarListEntry>
<Term>
        Int32
</Term>