diff --git a/src/runtime/c/data.h b/src/runtime/c/data.h
index 2b0e2d886..80e0742e9 100644
--- a/src/runtime/c/data.h
+++ b/src/runtime/c/data.h
@@ -120,13 +120,9 @@ struct PGF_INTERNAL_DECL PgfPGFRoot {
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wattributes"
 
-struct PgfPGF : public PgfPGFRoot {
-    DB db;
-
-    PGF_INTERNAL_DECL PgfPGF(const char* fpath) : db(fpath) {};
+struct PgfPGF : DB {
+    PGF_INTERNAL_DECL PgfPGF(const char* fpath) : DB(fpath) {};
     PGF_INTERNAL_DECL ~PgfPGF() {};
-
-    PGF_INTERNAL_DECL void set_root();
 };
 
 #pragma GCC diagnostic pop
diff --git a/src/runtime/c/db.cxx b/src/runtime/c/db.cxx
index 35a0a6286..dd9ccd240 100644
--- a/src/runtime/c/db.cxx
+++ b/src/runtime/c/db.cxx
@@ -309,6 +309,16 @@ DB::~DB() {
     close(fd);
 }
 
+void DB::sync()
+{
+    size_t size =
+        current_db->ms->top + size + sizeof(size_t);
+
+    int res = msync((void *) current_db->ms, size, MS_SYNC | MS_INVALIDATE);
+    if (res != 0)
+        throw std::system_error(errno, std::generic_category());
+}
+
 moffset DB::get_root_internal() {
     return ms->root_offset;
 }
diff --git a/src/runtime/c/db.h b/src/runtime/c/db.h
index 15e408c6b..457949958 100644
--- a/src/runtime/c/db.h
+++ b/src/runtime/c/db.h
@@ -86,6 +86,8 @@ public:
         current_db->set_root_internal(root.offset);
     }
 
+    static void sync();
+
 private:
     void init_state(size_t size);
 
diff --git a/src/runtime/c/pgf.cxx b/src/runtime/c/pgf.cxx
index 7d5e33a68..9eed30a02 100644
--- a/src/runtime/c/pgf.cxx
+++ b/src/runtime/c/pgf.cxx
@@ -33,9 +33,11 @@ PgfPGF *pgf_read(const char* fpath, PgfExn* err)
             }
 
             PgfReader rdr(&in);
-            rdr.read_pgf(pgf);
+            ref<PgfPGFRoot> pgf_root = rdr.read_pgf();
 
-            pgf->set_root();
+            pgf->set_root(pgf_root);
+
+            DB::sync();
         }
 
         return pgf;
@@ -53,13 +55,6 @@ PgfPGF *pgf_read(const char* fpath, PgfExn* err)
     return NULL;
 }
 
-void PgfPGF::set_root() {
-    ref<PgfPGFRoot> root = DB::malloc<PgfPGFRoot>();
-    root->major_version = major_version;
-    root->minor_version = minor_version;
-    DB::set_root(root);
-}
-
 PGF_API
 void pgf_free(PgfPGF *pgf)
 {
@@ -69,5 +64,5 @@ void pgf_free(PgfPGF *pgf)
 PGF_API
 PgfText *pgf_abstract_name(PgfPGF* pgf)
 {
-	return textdup(&(*pgf->abstract.name));
+	return textdup(&(*pgf->get_root<PgfPGFRoot>()->abstract.name));
 }
diff --git a/src/runtime/c/reader.cxx b/src/runtime/c/reader.cxx
index 28248b297..eb591b5df 100644
--- a/src/runtime/c/reader.cxx
+++ b/src/runtime/c/reader.cxx
@@ -407,7 +407,7 @@ ref<PgfAbsCat> PgfReader::read_abscat()
     return abscat;
 }
 
-void PgfReader::read_abstract(PgfAbstr* abstract)
+void PgfReader::read_abstract(ref<PgfAbstr> abstract)
 {
     abstract->name = read_name();
 	abstract->aflags = read_namespace<PgfFlag>(&PgfReader::read_flag);
@@ -415,12 +415,16 @@ void PgfReader::read_abstract(PgfAbstr* abstract)
     abstract->cats = read_namespace<PgfAbsCat>(&PgfReader::read_abscat);
 }
 
-void PgfReader::read_pgf(PgfPGFRoot *pgf)
+ref<PgfPGFRoot> PgfReader::read_pgf()
 {
+    ref<PgfPGFRoot> pgf = DB::malloc<PgfPGFRoot>();
+
     pgf->major_version = read_u16be();
     pgf->minor_version = read_u16be();
 
     pgf->gflags = read_namespace<PgfFlag>(&PgfReader::read_flag);
 
-    read_abstract(&pgf->abstract);
+    read_abstract(ref<PgfAbstr>::from_ptr(&pgf->abstract));
+
+    return pgf;
 }
diff --git a/src/runtime/c/reader.h b/src/runtime/c/reader.h
index ef9ba2e87..8fccfd05f 100644
--- a/src/runtime/c/reader.h
+++ b/src/runtime/c/reader.h
@@ -65,9 +65,9 @@ public:
 
     ref<PgfAbsFun> read_absfun();
     ref<PgfAbsCat> read_abscat();
-    void read_abstract(PgfAbstr* abstract);
+    void read_abstract(ref<PgfAbstr> abstract);
 
-    void read_pgf(PgfPGFRoot* pgf);
+    ref<PgfPGFRoot> read_pgf();
 
 private:
     std::istream *in;