Call level interface (CLI) driver enhancements for Db2 11.5.7

The CLI driver contains a number of major enhancements for the Db2 11.5.7 base product, its mod packs, and its fix packs. Each fix pack for a release is cumulative; that is, a particular fix pack contains the enhancements and new features that were included in previous fix packs.

Attention: This mod pack release is currently available for the following Db2 products:

Db2 on-premises
The single container deployments of Db2 Warehouse and IBM Integrated Analytics System (IIAS).
The container micro-service deployment of Db2 on Red Hat OpenShift.

Db2 on Cloud and Db2 Warehouse on Cloud will be updated to version 11.5.7 early in 2022.

11.5.7 enhancements

The Db2 11.5.7 release includes the following enhancements and new capabilities for the CLI driver:

Table 1. CLI enhancements and new capabilities in Db2 11.5.7
Enhancement	Description
Increased limit on FET_BUF_SIZE value to improve performance	For database applications that read large quantities of data sequentially, a larger fetch buffer size improves performance. The CLI driver FET_BUF_SIZE and FetchBufferSize keywords are used to configure the buffer size used by fetch requests in multiples of 32K. The previous upper limit of 256 KB can create a bottleneck when fetching large amount of data, as it involves a large number of TCP send and receive requests. With the release of Db211.5.7, the FET_BUF_SIZE is increased to around 10MB, which drastically reduces the number of TCP send and receive requests. This increase also improves performance on slower or congested networks, as well as networks where the physical distance is great between client and server.