# Accumulo WholeRowIterator with Python and Accumulo Thrift Proxy A brief example which will read from a table using Accumulo's WholeRowIterator. The WholeRowIterator serializes all columns in a row into one Key-Value pair. Because Accumulo does not enforce an explicit set of column families, in addition to the unlimited column qualifiers, this iterator should only be used when the cardinality of unique columns within a row is bounded by some upper limit (hundreds to maybe thousands of columns, depending on value size). When a row in Accumulo maps to a distinct element or object, this iterator is a very useful tool for grouping relevant data together into a single Key-Value instead of many. For small Key-Value pairs, this can also result in more efficient RPC calls as more data is sent back per Key-Value pair and less overhead is incurred.