set hive.exec.reducers .bytesper.reducer=<number>

The configuration parameter `hive.exec.reducers.bytes.per.reducer` is used to set the number of bytes of input data processed by a single reducer. This parameter is used to control the number of reducers required to process a particular job.

To set this parameter, you need to use the following syntax:

set hive.exec.reducers.bytes.per.reducer=<number>;

where `<number>` is the number of bytes of input data that should be processed by a single reducer. For example, if you want to set the number of bytes to 256 MB, you can use the following command:

set hive.exec.reducers.bytes.per.reducer=268435456;

Note that this parameter is only used when the number of reducers is not explicitly set for a particular job. If the number of reducers is set explicitly, then this parameter is ignored.