add logging with a reason why the cache is cleared (filter and field)

src/main/java/org/elasticsearch/action/admin/indices/cache/clear/TransportClearIndicesCacheAction.java

@@ -122,15 +122,15 @@ public class TransportClearIndicesCacheAction extends TransportBroadcastOperatio
             boolean clearedAtLeastOne = false;
             if (request.filterCache()) {
                 clearedAtLeastOne = true;
-                service.cache().filter().clear();
+                service.cache().filter().clear("api");
             }
             if (request.fieldDataCache()) {
                 clearedAtLeastOne = true;
                 if (request.fields() == null || request.fields().length == 0) {
-                    service.cache().fieldData().clear();
+                    service.cache().fieldData().clear("api");
                 } else {
                     for (String field : request.fields()) {
-                        service.cache().fieldData().clear(field);
+                        service.cache().fieldData().clear("api", field);
                     }
                 }
             }
@@ -146,10 +146,10 @@ public class TransportClearIndicesCacheAction extends TransportBroadcastOperatio
                 if (request.fields() != null && request.fields().length > 0) {
                     // only clear caches relating to the specified fields
                     for (String field : request.fields()) {
-                        service.cache().fieldData().clear(field);
+                        service.cache().fieldData().clear("api", field);
                     }
                 } else {
-                    service.cache().clear();
+                    service.cache().clear("api");
                 }
             }
             service.cache().invalidateCache();

src/main/java/org/elasticsearch/index/cache/IndexCache.java

@@ -138,9 +138,9 @@ public class IndexCache extends AbstractIndexComponent implements CloseableCompo
         bloomCache.clear(reader);
     }
 
-    public void clear() {
+    public void clear(String reason) {
-        filterCache.clear();
+        filterCache.clear(reason);
-        fieldDataCache.clear();
+        fieldDataCache.clear(reason);
         idCache.clear();
         queryParserCache.clear();
         bloomCache.clear();

src/main/java/org/elasticsearch/index/cache/field/data/FieldDataCache.java

@@ -36,9 +36,9 @@ public interface FieldDataCache extends IndexComponent, CloseableComponent {
 
     String type();
 
-    void clear(String fieldName);
+    void clear(String reason, String fieldName);
 
-    void clear();
+    void clear(String reason);
 
     void clear(IndexReader reader);
 

src/main/java/org/elasticsearch/index/cache/field/data/none/NoneFieldDataCache.java

@@ -54,12 +54,12 @@ public class NoneFieldDataCache extends AbstractIndexComponent implements FieldD
     }
 
     @Override
-    public void clear(String fieldName) {
+    public void clear(String reason, String fieldName) {
 
     }
 
     @Override
-    public void clear() {
+    public void clear(String reason) {
     }
 
     @Override

src/main/java/org/elasticsearch/index/cache/field/data/resident/ResidentFieldDataCache.java

@@ -125,7 +125,7 @@ public class ResidentFieldDataCache extends AbstractConcurrentMapFieldDataCache
                 ResidentFieldDataCache.this.expire = expire;
             }
             if (changed) {
-                clear();
+                clear("update_settings");
             }
         }
     }

src/main/java/org/elasticsearch/index/cache/field/data/support/AbstractConcurrentMapFieldDataCache.java

@@ -53,18 +53,20 @@ public abstract class AbstractConcurrentMapFieldDataCache extends AbstractIndexC
 
     @Override
     public void close() throws ElasticSearchException {
-        clear();
+        clear("close");
     }
 
     @Override
-    public void clear(String fieldName) {
+    public void clear(String reason, String fieldName) {
+        logger.debug("clearing field [{}] cache, reason [{}]", fieldName, reason);
         for (Map.Entry<Object, Cache<String, FieldData>> entry : cache.entrySet()) {
             entry.getValue().invalidate(fieldName);
         }
     }
 
     @Override
-    public void clear() {
+    public void clear(String reason) {
+        logger.debug("full cache clear, reason [{}]", reason);
         cache.clear();
     }
 

src/main/java/org/elasticsearch/index/cache/filter/FilterCache.java

@@ -47,7 +47,7 @@ public interface FilterCache extends IndexComponent, CloseableComponent {
 
     void clear(IndexReader reader);
 
-    void clear();
+    void clear(String reason);
 
     EntriesStats entriesStats();
 

src/main/java/org/elasticsearch/index/cache/filter/none/NoneFilterCache.java

@@ -60,7 +60,7 @@ public class NoneFilterCache extends AbstractIndexComponent implements FilterCac
     }
 
     @Override
-    public void clear() {
+    public void clear(String reason) {
         // nothing to do here
     }
 

src/main/java/org/elasticsearch/index/cache/filter/weighted/WeightedFilterCache.java

@@ -70,12 +70,13 @@ public class WeightedFilterCache extends AbstractIndexComponent implements Filte
 
     @Override
     public void close() throws ElasticSearchException {
-        clear();
+        clear("close");
         indicesFilterCache.removeRemovalListener(index.name());
     }
 
     @Override
-    public void clear() {
+    public void clear(String reason) {
+        logger.debug("full cache clear, reason [{}]", reason);
         for (Object readerKey : seenReaders.keySet()) {
             Boolean removed = seenReaders.remove(readerKey);
             if (removed == null) {