Executing reducers by leftmost two digits of Mapper output key
<p>I am using Apache MapReduce to parse raw data and load it to a database.</p>

<p>My Mapper parses raw lines of data from text files - each line gets a unique numeric ID (key) and a collection of key-value pairs (value).</p>

<p>My Reducer saves, for each line ID, the key-value pairs on a database.</p>

<p>I want to group the line ID by the <strong>leftmost two digits</strong> - so that the reducers will process IDs that starts with 10, then 11, 12 etc.
I don't want any Reducer to run on IDs that start with 12, before all the reducers that process IDS that start with 11 has finished.</p>

<p>Can it be implemented using Apache  MapReduce?</p>

<p>Thanks!</p>