EDM pool management is improved in DB2 12 for z/OS, which is especially beneficial to organizations running many concurrent threads with with large EDM pools specified.
Prior to DB2 12, the EDMDBDC, EDMSTMTC and EDM_SKELETON_POOL DSNZPARM values were used to allocate DBD cache, dynamic statement cache and EDM skeleton pool memory and the values could not be lowered past the specified installation vales.
With DB2 12 this bahvior is modified. No storage is initially allocated for these 3 EDM structures. Instead, storage is allocated by DB2 as it is needed while being used. If more stroage is required When the specified DSNZPARM values are reached then structures that are not currently in use are removed to tkeep the storatge that is in use below the specified values.
This should result in more effective and efficient EDM storage usage and allocation. Some larger shops may see higher real storage usage by DB2.
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