Improve application performance
These topics suggest ways to improve performance of HCL Informix® ODBC Driver applications.
- Error checking during data transfer
The IFX_LOB_XFERSIZE environment variable is used to specify the number of kilobytes in a CLOB or BLOB to transfer from a client application to the database server before checking whether an error has occurred. - Enable delimited identifiers in ODBC
By default delimited identifiers are disabled when connecting through ODBC. - Connection level optimizations
Establishing a connection to a database is an expensive process. Optimally, an application performs as many tasks as possible while a connection is open. - Optimizing query execution
There are several items you must consider when using prepared SQL queries. - Insert multiple rows
Use an insert cursor to efficiently insert rows into a table in bulk. - Automatically freeing a cursor
When an application uses a cursor, it usually sends a FREE statement to the database server to deallocate memory assigned to a cursor after it no longer needs that cursor. - Delay execution of the SQL PREPARE statement
You can defer execution of the SQLPrepare statement by enabling the deferred-PREPARE feature. - Set the fetch array size for simple-large-object data
To reduce the network overhead for fetches involving multiple rows of simple-large-object data, you can set the array size. - The SPL output parameter feature
HCL Informix ODBC Driver supports the ODBC defined method of getting the return value from a database procedure. - OUT and INOUT parameters
As of Version 4.10, HCL Informix Client Software Development Kit supports the use of OUT and INOUT parameters during execution of SPL. - Asynchronous execution
Design your application to take advantage of data sources that support asynchronous execution. Asynchronous calls do not perform faster, but well-designed applications appear to run more efficiently. - Update data with positioned updates and deletes
Although positioned updates do not apply to all types of applications, try to use positioned updates and deletes whenever possible. - BIGINT and BIGSERIAL data types
BIGINT and BIGSERIAL data types have the same range of values as INT8 and SERIAL8 data types. - Message transfer optimization
If you activate the message transfer optimization feature (OPTMSG), the driver minimizes message transfers with the database server for most HCL Informix ODBC functions.
Parent topic: Informix ODBC Driver Guide