CACHESIZE statement

Use the CACHESIZE statement to specify the maximum amount of storage that can be allocated by the resolver to manage cached records.

Tip: When the CACHESIZE statement is specified with the NOCACHE statement, the CACHESIZE operand is ignored.

Syntax


   .-CACHESIZE(200M)-------.   
>>-+-----------------------+-----------------------------------><
   '-CACHESIZE(cachesizeM)-'

Parameters

cachesize M: Specifies the maximum amount of 64-bit private virtual storage that the resolver can use to maintain cache information. This limit should be expressed as a number followed by an M (which represents 1 048 576 bytes). The cachesize value must be in the range 1M - 999M. The default is 200M.

Examples

Use the CACHESIZE statement to set 10 M as the maximum cache size value:

CACHESIZE(10M)

Usage notes

For planning purposes, 1 megabyte of storage can contain between 400 and 450 cache entries. The actual values can vary depending on the amount of storage needed to hold cache infrastructure control blocks used to represent the entries and the name servers providing the information.
The resolver acquires cache storage incrementally as needed, up to the maximum specified by the CACHESIZE operand. Because storage is acquired incrementally, there is no penalty for specifying a CACHESIZE value significantly greater than the expected maximum amount of storage required. This avoids storage constraint processing during spikes in the amount of information being cached. Consider specifying a value at least fifty percent larger than the amount of storage you actually expect to be used for cache entries.
You can increment the value of cachesize M dynamically by issuing the MODIFY RESOLVER,REFRESH,SETUP=resolver_setup_filename command. You cannot decrease the value of cachesize M dynamically. If you attempt to lower the value of CACHESIZE dynamically, the MODIFY command fails and message EZZ9306I is issued. To decrease the value of cachesize M, you must stop and restart the resolver. Alternatively, update the resolver setup file to indicate NOCACHE and issue a MODIFY RESOLVER,REFRESH,SETUP=resolver_setup_filename command to first stop resolver caching, and then issue a second MODIFY RESOLVER,REFRESH,SETUP=resolver_setup_filename command that both restarts resolver caching and decrease the value of cachesize M.