A match key filter restricts the data in the Histogram and the Match Keys List to the subset of match keys that meets the filter condition. By default, no filter is defined—all records in the match key table are displayed.

The filter condition specifies the beginning string sequence for qualified match keys, evaluated from left to right. For example, to view only match keys beginning with the letter M, you would select M for the filter. To further restrict match keys and view data for only the match keys that start with the letters MD you would add the letter D to the filter. The longer the filter expression, the more restrictive the display.