The following connection options can enhance driver performance. You can also enhance performance through efficient application design. Refer to "Designing ODBC Applications for Performance Optimization" in the DataDirect Connect Series for ODBC Reference for details.
Array Size (ArraySize): If this connection string attribute is set appropriately, the driver can improve performance of your application by reducing the number of round trips on the network. For example, if your application normally retrieves 200 rows, it is more efficient for the driver to retrieve 200 rows at one time over the network than to retrieve 50 rows at a time during four round trips over the network.
Default Buffer Size for Long/LOB Columns (DefaultLongDataBuffLen): To improve performance when your application fetches images, pictures, or long text or binary data, a buffer size can be set to accomodate the maximum size of the data. The buffer size should only be large enough to accommodate the maximum amount of data retrieved; otherwise, performance is reduced by transferring large amounts of data into an oversized buffer. If your application retrieves more than 1 MB of data, the buffer size should be increased accordingly.
Remove Column Qualifiers (RemoveColumnQualifiers): When using the driver with Microsoft Access in creating a linked table, it is highly recommended that you do not specify an index. Specifying an index causes Access to execute a Select statement for each row, which results in very slow performance.
Use Current Schema for Catalog Functions (UseCurrentSchema): If your application needs to access database objects owned only by the current user, then performance can be improved. In this case, the Use Current Schema for Catalog Functions option must be enabled. When this option is enabled, the driver returns only database objects owned by the current user when executing catalog functions. Calls to catalog functions are optimized by grouping queries. Enabling this option is equivalent to passing the Logon ID used on the connect as the Schema Name arguement to catalog functions.
