KDB IPC 2GB limit

[hyper-nova]

I am aware that since KDB version 3.4 the 2GB IPC (network) message limit was raised from 2GB to 1TB.

Changes in 3.4 – Releases – kdb+ and q documentation - kdb+ and q documentation

The 2GB limit is a result of the message length field in the serialized message data, which is a 32 bit value.

I am querying a KDB system and the message size limit still appears to be limited to 2GB.

What, if anything, is required to increase this message size limit?

• Is any configuration option required?
• Does the client have to send some flag when making a request over IPC?

[rocuinneagain]

The capability byte is used during the connection handshake

Writing "hello\3\0" to a socket returns 0x03. What is this and is that expected?

Interprocess communication | Developing | kdb+ and q documentation - kdb+ and q documentation After a client has opened a socket to the server, it sends a null-terminated ASCII string "username:password\N" where \N is a single byte which represents the client’s capability with respect to compression, timestamp|timespan and UUID, e.g. "myname:mypassword\3" .

For the C API:
C API reference | Interfaces | kdb+ and q documentation - kdb+ and q documentation

  During the initial handshake of a connection, each side’s capability is exchanged, and the common maximum is chosen for the connection. By setting the capability parameter for `khpunc`, the default message-size limit for this connection can be raised from 2GB to 1TB. e.g.
  
  
  int handle=khpunc("hostname",5000,"user:password",timeout,1);