Ingres 9.2 Migration Guide - Actian

Increased Maximum Size of Character Data TypesSUBSTRING FunctionThe ANSI compliant SUBSTRING function has been added to the SQL syntax.The SUBSTRING function is often easier to use than combinations of LEFT andSHIFT functions that Ingres traditionally supported. The syntax is:substring(string-expr from start-column for length)and the for length clause is optional.New Aggregate FunctionsAdditional aggregate functions for statistical analysis have been added:• The function corr computes a correlation coefficient• Functions covar_samp and covar_pop compute covariance• A collection of regr_xx functions generate regression analysis resultsFor details, see the SQL Reference Guide.Increased Maximum Size of Character Data TypesPrior to Ingres 2.6, character data types were limited to a maximum size of2000 bytes; this restriction was imposed when the maximum size of a row waslimited to 2 KB. This limit is increased to 32000 bytes, the maximum row sizesupported in Ingres 2.6.User-Visible DBA EnhancementsEnhancements have been made to internal performance that concern auditdbutility, copydb utility, raw location support, and GatherWrite threads.Usermod UtilityIngres now includes a usermod utility that allows users to run the modifycommands on user tables. Like sysmod, which modifies system catalogs, thisutility is useful for maintaining user tables on a regular basis.Running this utility regularly, or when the table has excess overflow pages,improves performance of user applications.194 Migration Guide