Date math in query_string caches now()

fixes #2808

Author: kimchy

src/main/java/org/apache/lucene/queryParser/QueryParserSettings.java

@@ -66,6 +66,11 @@ public class QueryParserSettings {
     float tieBreaker = 0.0f;
     boolean useDisMax = true;
 
+    public boolean isCacheable() {
+        // a hack for now :) to determine if a query string is cacheable
+        return !queryString.contains("now");
+    }
+
     public String queryString() {
         return queryString;
     }

src/main/java/org/elasticsearch/index/cache/query/parser/QueryParserCache.java

@@ -25,7 +25,8 @@
 import org.elasticsearch.index.IndexComponent;
 
 /**
- *
+ * The main benefit of the query parser cache is to not parse the same query string on different shards.
+ * Less about long running query strings.
  */
 public interface QueryParserCache extends IndexComponent, CloseableComponent {
 

src/main/java/org/elasticsearch/index/cache/query/parser/resident/ResidentQueryParserCache.java

@@ -49,8 +49,8 @@ public class ResidentQueryParserCache extends AbstractIndexComponent implements
     public ResidentQueryParserCache(Index index, @IndexSettings Settings indexSettings) {
         super(index, indexSettings);
 
-        this.maxSize = indexSettings.getAsInt("index.cache.field.max_size", componentSettings.getAsInt("max_size", 100));
-        this.expire = indexSettings.getAsTime("index.cache.field.expire", componentSettings.getAsTime("expire", null));
+        this.maxSize = componentSettings.getAsInt("max_size", 100);
+        this.expire = componentSettings.getAsTime("expire", null);
         logger.debug("using [resident] query cache with max_size [{}], expire [{}]", maxSize, expire);
 
         CacheBuilder cacheBuilder = CacheBuilder.newBuilder().maximumSize(maxSize);
@@ -68,7 +68,9 @@ public Query get(QueryParserSettings queryString) {
 
     @Override
     public void put(QueryParserSettings queryString, Query query) {
-        cache.put(queryString, query);
+        if (queryString.isCacheable()) {
+            cache.put(queryString, query);
+        }
     }
 
     @Override