--- a/PostgreSQL/CMakeLists.txt	Fri Jan 04 13:51:52 2019 +0100
+++ b/PostgreSQL/CMakeLists.txt	Fri Jan 04 14:43:35 2019 +0100
@@ -54,6 +54,7 @@
 EmbedResources(
   POSTGRESQL_PREPARE_INDEX    ${CMAKE_SOURCE_DIR}/Plugins/PrepareIndex.sql
   POSTGRESQL_CREATE_INSTANCE  ${CMAKE_SOURCE_DIR}/Plugins/CreateInstance.sql
+  POSTGRESQL_FAST_TOTAL_SIZE  ${CMAKE_SOURCE_DIR}/Plugins/FastTotalSize.sql
   )
 
 add_library(OrthancPostgreSQLIndex SHARED

--- a/PostgreSQL/Plugins/CreateInstance.sql	Fri Jan 04 13:51:52 2019 +0100
+++ b/PostgreSQL/Plugins/CreateInstance.sql	Fri Jan 04 14:43:35 2019 +0100
@@ -10,7 +10,8 @@
   OUT patientKey BIGINT,
   OUT studyKey BIGINT,
   OUT seriesKey BIGINT,
-  OUT instanceKey BIGINT) AS $$
+  OUT instanceKey BIGINT) AS $body$
+
 BEGIN
   SELECT internalId FROM Resources INTO instanceKey WHERE publicId = instance AND resourceType = 3;
 
@@ -63,4 +64,5 @@
     isNewInstance := 1;
   END IF;  
 END;
-$$ LANGUAGE plpgsql;
+
+$body$ LANGUAGE plpgsql;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PostgreSQL/Plugins/FastTotalSize.sql	Fri Jan 04 14:43:35 2019 +0100
@@ -0,0 +1,41 @@
+CREATE TABLE GlobalIntegers(
+       key INTEGER PRIMARY KEY,
+       value BIGINT);
+
+INSERT INTO GlobalIntegers
+SELECT 0, CAST(COALESCE(SUM(compressedSize), 0) AS BIGINT) FROM AttachedFiles;
+
+INSERT INTO GlobalIntegers
+SELECT 1, CAST(COALESCE(SUM(uncompressedSize), 0) AS BIGINT) FROM AttachedFiles;
+
+
+
+CREATE FUNCTION AttachedFileIncrementSizeFunc() 
+RETURNS TRIGGER AS $body$
+BEGIN
+  UPDATE GlobalIntegers SET value = value + new.compressedSize WHERE key = 0;
+  UPDATE GlobalIntegers SET value = value + new.uncompressedSize WHERE key = 1;
+  RETURN NULL;
+END;
+$body$ LANGUAGE plpgsql;
+
+CREATE FUNCTION AttachedFileDecrementSizeFunc() 
+RETURNS TRIGGER AS $body$
+BEGIN
+  UPDATE GlobalIntegers SET value = value - old.compressedSize WHERE key = 0;
+  UPDATE GlobalIntegers SET value = value - old.uncompressedSize WHERE key = 1;
+  RETURN NULL;
+END;
+$body$ LANGUAGE plpgsql;
+
+
+
+CREATE TRIGGER AttachedFileIncrementSize
+AFTER INSERT ON AttachedFiles
+FOR EACH ROW
+EXECUTE PROCEDURE AttachedFileIncrementSizeFunc();
+
+CREATE TRIGGER AttachedFileDecrementSize
+AFTER DELETE ON AttachedFiles
+FOR EACH ROW
+EXECUTE PROCEDURE AttachedFileDecrementSizeFunc();

--- a/PostgreSQL/Plugins/PostgreSQLIndex.cpp	Fri Jan 04 13:51:52 2019 +0100
+++ b/PostgreSQL/Plugins/PostgreSQLIndex.cpp	Fri Jan 04 14:43:35 2019 +0100
@@ -187,6 +187,27 @@
       }
     }
 
+    {
+      PostgreSQLTransaction t(*db);
+
+      int hasFastTotalSize = 0;
+      if (!LookupGlobalIntegerProperty(hasFastTotalSize, *db, t,
+                                       Orthanc::GlobalProperty_GetTotalSizeIsFast) ||
+          hasFastTotalSize != 1)
+      {
+        LOG(INFO) << "Installing the FastTotalSize extension";
+
+        std::string query;
+        Orthanc::EmbeddedResources::GetFileResource
+          (query, Orthanc::EmbeddedResources::POSTGRESQL_FAST_TOTAL_SIZE);
+        db->Execute(query);
+
+        SetGlobalIntegerProperty(*db, t, Orthanc::GlobalProperty_GetTotalSizeIsFast, 1);
+
+        t.Commit();
+      }
+    }
+
     return db.release();
   }
 
@@ -220,6 +241,34 @@
   }
 
 
+  uint64_t PostgreSQLIndex::GetTotalCompressedSize()
+  {
+    // Fast version if extension "./FastTotalSize.sql" is installed
+    DatabaseManager::CachedStatement statement(
+      STATEMENT_FROM_HERE, GetManager(),
+      "SELECT value FROM GlobalIntegers WHERE key = 0");
+
+    statement.SetReadOnly(true);
+    statement.Execute();
+
+    return static_cast<uint64_t>(ReadInteger64(statement, 0));
+  }
+
+  
+  uint64_t PostgreSQLIndex::GetTotalUncompressedSize()
+  {
+    // Fast version if extension "./FastTotalSize.sql" is installed
+    DatabaseManager::CachedStatement statement(
+      STATEMENT_FROM_HERE, GetManager(),
+      "SELECT value FROM GlobalIntegers WHERE key = 1");
+
+    statement.SetReadOnly(true);
+    statement.Execute();
+
+    return static_cast<uint64_t>(ReadInteger64(statement, 0));
+  }
+
+
   void PostgreSQLIndex::CreateInstance(OrthancPluginCreateInstanceResult& result,
                                        const char* hashPatient,
                                        const char* hashStudy,

--- a/PostgreSQL/Plugins/PostgreSQLIndex.h	Fri Jan 04 13:51:52 2019 +0100
+++ b/PostgreSQL/Plugins/PostgreSQLIndex.h	Fri Jan 04 14:43:35 2019 +0100
@@ -71,9 +71,14 @@
     }
 
     virtual int64_t CreateResource(const char* publicId,
-                                   OrthancPluginResourceType type);
+                                   OrthancPluginResourceType type)
+      ORTHANC_OVERRIDE;
 
-    virtual bool HasCreateInstance() const
+    virtual uint64_t GetTotalCompressedSize() ORTHANC_OVERRIDE;
+
+    virtual uint64_t GetTotalUncompressedSize() ORTHANC_OVERRIDE;
+    
+    virtual bool HasCreateInstance() const  ORTHANC_OVERRIDE
     {
       return true;
     }
@@ -83,7 +88,8 @@
                                 const char* hashPatient,
                                 const char* hashStudy,
                                 const char* hashSeries,
-                                const char* hashInstance);
+                                const char* hashInstance)
+      ORTHANC_OVERRIDE;
 #endif
   };
 }