Error 4020



Message text

While reading characters from the client, the receiving buffer has been detected to be too small.


All client/server communication occurs over a network using packets. Clients initiate a connection to the server. The connection sends client requests and server responses.

Error 4020 is raised when the server detects an overflow in the destination buffer while reading one or more characters from the client. The error breaks the connection to the server.

Possible reasons for error 4020 include:


  1. Collect all relevant information about the circumstances in which the error occurred: character set differences on client and server, changed or new applications, recent changes in the network configuration, and so on.

  2. Check for coding errors in the application which may be causing incorrectly sized packets to be sent.

  3. Check for possible packet corruption within the network.

  4. Check the network configuration. For example, if there is 7-bit communication at one end, and 8-bit at the other end, check that the network is properly configured to handle this setup.

  5. Check that Adaptive Server is correctly configured to work with the underlying network packet size or buffer size on your system. Relevant server parameters include:

    default network packet size
    maximum network packet size
    total memory (pre-12.5) or max memory (version 12.5 and later)

Versions in which this error is raised

All versions