Buffer data transfers for a distributed query

Informix® uses several factors to determine the size of the buffer that sends and receives data to and from a remote server.

The server uses the following factors to determine the buffer size:
  • The row size

    The database server calculates the row size by summing the average move size (if available) or the length (from the syscolumns system catalog table) of the columns.

  • The setting of the FET_BUF_SIZE environment variable on the client

    You might be able to reduce the size and number of data transfers by using the FET_BUF_SIZE environment variable to increase the size of the buffer that the database server uses to send and receive rows to and from the remote database server.

    The minimum buffer size is 1024 or 2048 bytes, depending on the row size. If the row size is larger than either 1024 or 2048 bytes, the database server uses the FET_BUF_SIZE value.

    For more information about the FET_BUF_SIZE environment variable, see the IBM® Informix Guide to SQL: Reference.

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