Federation server enhancements

Db2 11.5.7 provides enhanced access to data sources in a Federation Server environment.

Attention: This mod pack release is currently available for the following Db2 products: Db2 as a Service and Db2 Warehouse SaaS will be updated to version 11.5.7 early in 2022.
Enhancement Description
Federation pushdown capability for running fetch first n row (FFNR) queries against Snowflake data sources Db2 has added Snowflake datastore cloud-service to the list of supported federated data sources for FFNR queries. This improved support means that Db2 is now able to take the fetch clause portion of a SQL query and push it down to the Snowflake data source. See Federation server enhancements for the 11.5.4 release for a list of other supported data sources.
Federated procedure support in fenced wrappers

With the release of Db2 11.5.7, federated procedures can now be created in fenced wrappers as well as unfenced wrappers. Supported wrapper options include Db2 DRDA, Oracle Net8, and native SQL Server. See Data source support for federated features for the Db2 11.5.7 supported features.
Improve pushdown analysis on the blank-padded string comparison semantics Pushdown is improved for SQL statements that use string comparison predicates (operations). This enhancement results in better performance, and is available for a number of data sources:
  • Greenplum
  • PostgreSQL
  • Hive
  • MySQL CE
  • Hana
  • MariaD
  • Impala
  • Informix
  • Snowflake
  • Teradata
  • MS SQL Server
  • Spark
  • Netezza
COLUMN_LENGTH_AUTO_VARIATION for the DRDA wrapper The COLUMN_LENGTH_AUTO_VARIATION option controls whether the length of nickname columns with CHAR and VARCHAR data types is automatically extended.
  • If set to Y, the column length is automatically extended based on a factor derived from the code pages of the federation server and the remote data source. If the resulting length exceeds the maximum allowed, the excess characters are truncated.

  • If set to N, the column length remains unchanged, and any characters exceeding the length are truncated.

    The default value for this option is Y, and it applies specifically to the DRDA UDB wrapper.