add logarithmic scaling for the y-axis

Often we have a few very high values and a lot
low values. With a linearly scaled y-axis the
plot is mostly useless.

pdb-ui/src/main/resources/resources/js/search.js

@@ -96,6 +96,7 @@ function plot(event){
 	request['limit'] = parseInt($('#search-limit-value').val());
 	request['dateFrom'] = $('#search-date-from').val();
 	request['dateRange'] = $('#search-date-range').val();
+	request['axisScale'] = $('#search-y-axis-scale').val();
 	
 	
 	var success = function(response){

pdb-ui/src/main/resources/templates/main.html

@@ -46,6 +46,13 @@
 			<option value="1 month">
 		</datalist>
 		
+		<label for="search-y-axis-scale">y-axis:</label>
+		<select id="search-y-axis-scale">
+			<option value="LINEAR" selected="selected">linear</option>
+			<option value="LOG10">log 10</option>
+			<option value="LOG2">log 2</option>
+		</select>
+		
 		<button id="search-submit"><i class="fa fa-area-chart"> Plot</i></button>
 	</div>
 	<div id="result-view">