diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/server/api/v1/QueryApiLogger.java b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/server/api/v1/QueryApiLogger.java
index a03daa6f49aef0dec70d0ef06bffa289e5c409d2..daf117d51e35fc4f41572aa6bde57dc9d8e072d6 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/server/api/v1/QueryApiLogger.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/server/api/v1/QueryApiLogger.java
@@ -111,7 +111,7 @@ class QueryApiLogger extends AbstractServerLogger implements IQueryApiServer
             String dataStoreCode, String serviceKey, Map<String, Object> parameters)
     {
         logAccess(sessionToken, "create_report_from_aggregation_service",
-                "DATA_STORE(%s) SERVICE(%s) PARAMETERS(%s)", dataStoreCode, serviceKey, parameters);
+                "DATA_STORE(%s) SERVICE(%s) PARAMETER_KEYS(%s)", dataStoreCode, serviceKey, parameters.keySet());
         return null;
     }
 
diff --git a/openbis_api/source/java/ch/ethz/sis/openbis/generic/asapi/v3/dto/service/execute/AbstractExecutionOptionsWithParameters.java b/openbis_api/source/java/ch/ethz/sis/openbis/generic/asapi/v3/dto/service/execute/AbstractExecutionOptionsWithParameters.java
index 3e71de2ce6a9e3547ac4eff45f28e6325e63000f..a3b8efc0c5bb6088f3d3502feb23356afa5a9110 100644
--- a/openbis_api/source/java/ch/ethz/sis/openbis/generic/asapi/v3/dto/service/execute/AbstractExecutionOptionsWithParameters.java
+++ b/openbis_api/source/java/ch/ethz/sis/openbis/generic/asapi/v3/dto/service/execute/AbstractExecutionOptionsWithParameters.java
@@ -24,13 +24,12 @@ import ch.systemsx.cisd.base.annotation.JsonObject;
 
 /**
  * @author Franz-Josef Elmer
- *
  */
 @JsonObject("as.dto.service.execute.AbstractExecutionOptionsWithParameters")
 public abstract class AbstractExecutionOptionsWithParameters<EO extends AbstractExecutionOptionsWithParameters<EO, V>, V> implements Serializable
 {
     private static final long serialVersionUID = 1L;
-    
+
     private final Map<String, V> parameters = new HashMap<String, V>();
 
     @SuppressWarnings("unchecked")
@@ -48,7 +47,7 @@ public abstract class AbstractExecutionOptionsWithParameters<EO extends Abstract
     @Override
     public String toString()
     {
-        return getClass().getSimpleName() + ": parameters=" + parameters;
+        return getClass().getSimpleName() + ": parameterKeys=" + parameters.keySet();
     }
 
 }