#include <db_cxx.h>

int
DbEnv::set_cache_max(u_int32_t gbytes, u_int32_t bytes);

int
DbEnv::get_cache_max(u_int32_t *gbytesp, u_int32_t *bytesp);

The DbEnv::set_cache_max method sets the maximum cache size, in bytes. The specified size is rounded to the nearest multiple of the cache region size, which is the initial cache size divided by the number of regions specified to the DbEnv::set_cachesize method. If no value is specified, it defaults to the initial cache size.

The database environment's maximum cache size may also be configured using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_cache_max", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

The DbEnv::set_cache_max method configures a database environment, not only operations performed using the specified DbEnv handle.

The DbEnv::set_cache_max method may be called at any time during the life of the application.

The DbEnv::set_cache_max method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

• The mp_mmapsize parameter is the maximum file size, in bytes, for a file to be mapped into the process address space.

The DbEnv::set_cache_max method may fail and throw DbException, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

• If the method was called after DbEnv::open was called; or if an invalid flag value or parameter was specified.

The DbEnv::get_cache_max method returns the maximum size of the cache.

The DbEnv::get_cache_max method may be called at any time during the life of the application.

The DbEnv::get_cache_max method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

• The bytesp parameter references memory into which the additional bytes of memory in the cache is copied.

• The gbytesp parameter references memory into which the gigabytes of memory in the cache is copied.