Adaptive Server 15.0 uses more memory than previous releases, allocating more memory for the data server, procedure cache, and named caches. Many system procedures in this release now call other procedures. Query optimization in Adaptive Server 15.0 is much more complex than in earlier releases, so sites with minimally configured procedure caches are likely to run out of space.
For example, Adaptive Server 15.0 uses in-memory sorting and grouping algorithms, and requires additional procedure cache space for the auxiliary scan buffers used to track sort buffers and additional memory for sorting. Since Adaptive Server 15.0 uses in-memory sorting instead of worktables, the additional memory requirement is in whichever data cache tempdb is bound.
Although it is impossible to predict how much additional memory is required, the additional requirements are probably only a small percentage above what you currently allocate (somewhere between 5 and 25 percent). Carefully monitor memory usage after upgrading. Use sp_helpcache to check cache sizes before and after the upgrade and adjust memory, if necessary, to restore the original value of the default data cache after the upgrade is complete.
See the System Administration Guide, Volume 2 for information on configuring memory and data caches; see the Performance and Tuning Guide: Basics for more information on memory issues.
