What is 'Compatibility Mode' in ASE 15.0.3 ESD#1?

At the end of March 2009, version 15.0.3 ESD#1 of Sybase Adaptive Server Enterprise (ASE) was released. This ESD
contained a new feature named 'compatibility mode'.

Compatibility mode is a query processing enhancement in ASE 15.0.3 ESD#1 that allows qualifying T‐SQL queries to
be processed with a method of query optimization and query execution very similar to that used in ASE 12.5,
instead of using the ASE 15 query processing algorithms.

Compatibility mode can be enabled server‐wide for the entire ASE server, as well as for an individual session only.
By default, compatibility mode is disabled. To enable it on server level, set the configuration parameter 'enable
compatibility mode' to 1 (when set to 0, it is disabled):

        

sp_configure 'enable compatibility mode', 1

To override the server‐wide compatibility mode setting for an individual session, use this syntax:

      

  set compatibility_mode on

At the end of March 2009, version 15.0.3 ESD#1 of Sybase Adaptive Server Enterprise (ASE) was released. This ESD
contained a new feature named 'compatibility mode'.

Compatibility mode is a query processing enhancement in ASE 15.0.3 ESD#1 that allows qualifying T‐SQL queries to
be processed with a method of query optimization and query execution very similar to that used in ASE 12.5,
instead of using the ASE 15 query processing algorithms.

Compatibility mode can be enabled server‐wide for the entire ASE server, as well as for an individual session only.
By default, compatibility mode is disabled. To enable it on server level, set the configuration parameter 'enable
compatibility mode' to 1 (when set to 0, it is disabled):

        

sp_configure 'enable compatibility mode', 1

To override the server‐wide compatibility mode setting for an individual session, use this syntax:

      

  set compatibility_mode on