diff --git a/sql/clusters.dot b/sql/clusters.dot
index 7a355712..8100f745 100644
--- a/sql/clusters.dot
+++ b/sql/clusters.dot
@@ -1,98 +1,109 @@
 
 subgraph "logical_grouping" {
 	style = rounded;
 	bgcolor = gray95;
 	color = gray;
 	
 	subgraph cluster_meta {
 		label = <<b>schema versioning</b><br /> version: @@VERSION@@>;
 		dbversion;
 	}
 
 	subgraph cluster_content {
 		label = <<b>content</b>>;
 		content;
 		skipped_content;
 	}
 
 	subgraph cluster_directory {
 		label = <<b>directories</b>>;
 		directory;
 		directory_entry_dir;
 		directory_entry_file;
 		directory_entry_rev;
 	}
 
 	subgraph cluster_revision {
 		label = <<b>revisions</b>>;
 		revision;
 		revision_history;
 		person;
 	}
 
 	subgraph cluster_release {
 		label = <<b>releases</b>>;
 		release;
 	}
 
 	subgraph cluster_snapshots {
 		label = <<b>snapshots</b>>;
 		occurrence;
 		occurrence_history;
 	}
 
 	subgraph cluster_origins {
 		label = <<b>origins</b>>;
 		origin;
 		fetch_history;
 		origin_visit;
 	}
 
 	subgraph cluster_entity {
 		label = <<b>entities</b>>;
 		entity;
 		entity_history;
 		entity_equivalence;
 		listable_entity;
 		list_history;
 	}
 
 	subgraph cluster_provenance {
 		label = <<b>provenance</b>>;
 		cache_revision_origin;
 		cache_content_revision;
 		cache_content_revision_processed;
 	}
 
         subgraph cluster_data_mining {
                 label = <<b>data mining</b>>;
                 content_mimetype;
                 content_ctags;
                 content_language;
                 fossology_license;
                 content_fossology_license;
                 indexer_configuration;
         }
 
 	{
 		edge [style = dashed];
 
 		# "rtcolN" identifies the N-th row in a table, as a source
 		# "ltcolN" identifies the N-th row in a table, as a destination
 		"directory_entry_dir":rtcol2 -> "directory":ltcol1;
 		"directory_entry_file":rtcol2 -> "content":ltcol2;
 		"directory_entry_file":rtcol2 -> "skipped_content":ltcol2;
 		"directory_entry_rev":rtcol2 -> "revision":ltcol1;
 		"directory":rtcol2 -> "directory_entry_dir":ltcol1;
 		"directory":rtcol3 -> "directory_entry_file":ltcol1;
 		"directory":rtcol4 -> "directory_entry_rev":ltcol1;
 		"occurrence":rtcol3 -> "revision":ltcol1;
 		"occurrence_history":rtcol3 -> "revision":ltcol1;
 		"release":rtcol2 -> "revision":ltcol1;
 		"revision":rtcol9 -> "directory":ltcol1;
 		"revision_history":rtcol2 -> "revision":ltcol1;
 		"entity_history":rtcol3 -> "entity_history":ltcol2;
 		"entity_history":rtcol10 -> "listable_entity":ltcol1;
 	}
 
+	subgraph cluster_metadata {
+                label = <<b>metadata</b>>;
+                content_metadata;
+                revision_metadata;
+	}
+
+	subgraph cluster_statistics {
+                label = <<b>statistics</b>>;
+                object_counts;
+	}
+
 }