FetchCount Parameter (Client-Side) - Aster Client

The recommended setting for the client-side FetchCount parameter is the maximum number of rows that can fit in the Mule Fetch message, which is based on the MuleFetchMessageSize parameter and the row size.

FetchCount = floor (MuleFetchMessageSize / row size)

Setting the FetchCount parameter to a larger value causes the client to wait in a loop until the requested number of rows are fetched by using multiple round trips between the client and server.

Setting the FetchCount parameter to a smaller value does not make use of the full capacity of MuleFetchMessageSize.

This sample case provides an example of how to determine the best value for the FetchCount parameter:

Table Schema:  "tab_1m_rows_fixed_column_small"
Column    |       Type        | Modifiers
-----------+-------------------+-----------
t_char    | character(1024)   |

• The size of each row: 1KB
• The number of rows to be fetched: 1,000,000
• The MuleFetchMessageSize parameter value: 1MB (1024KB)

Calculating the FetchCount:

FetchCount = floor (MuleFetchMessageSize / row size)

FetchCount = floor (1024 KB / 1KB)

FetchCount = 1024 (Therefore, the value of the FetchCount parameter should be set to a value of 1000 rows.)

This table shows that a value of 1000 for the FetchCount parameter provides the best total time result for this particular sample case: