With enhanced logical record cache support, you can create logical record caches that have a maximum entry size of 2 GB. With the ability to define a larger logical record cache and a larger cache entry size, you have more flexibility with the kind of data that you can store in a logical cache.
When you create a traditional logical record cache, the size of memory that is allocated is the number of entries × the maximum entry size. The maximum entry size for a traditional logical record cache is 4 KB. When you create an enhanced logical record cache, the size of memory that is allocated is based on the specified total size of the cache.
For traditional logical record caches, each entry is assigned the same fixed size. You can store less data in each entry, but the maximum space is allocated and available for each entry. For enhanced logical record caches, each entry can be assigned a different size of memory. The z/TPF system automatically adjusts the size of memory based on the amount of data that you write to the entry at any point in time. The size of each entry is limited by the maximum entry size, but the size is not fixed and can be smaller. The memory is distributed in the form of 4 KB chunks to cache entries as needed.
When you create a logical record cache with the newCache or tpf_newCache_ext function, the value that you specify for the data_length parameter controls whether a traditional logical record cache or an enhanced logical record cache is created.
The ZCACH command displays and the data collection and reduction utility were both enhanced to provide more useful information.
For more information about enhanced logical record cache support, see the product documentation in IBM Knowledge Center.