Library Version 18.1.40

DbEnv::set_cache_max()
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## DbEnv::set_cache_max()

    #include <db_cxx.h>

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

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 maximum cache size in bytes, specified in two parts: the gigabytes of cache and the additional bytes of cache. 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 must be called prior to opening the database environment.

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.

### Parameters

#### gbytes

The gbytes parameter specifies the number of bytes which, when added to the bytes parameter, specifies the maximum size of the cache.

#### bytes

The bytes parameter specifies the number of bytes which, when added to the gbytes parameter, specifies the maximum size of the cache.

### Errors

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

#### EINVAL

An invalid flag value or parameter was specified.

### Class

DbEnv

### See Also

Database Environments and Related Methods

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