* Require Berkeley DB 4.4.

* Checkpoint after an upgrade.

externals/Makefile.am

@@ -1,11 +1,11 @@
 # Berkeley DB
 
-DB = db-4.3.28.NC
+DB = db-4.4.16.NC
 
 $(DB).tar.gz:
 	@echo "Nix requires Berkeley DB to build."
-	@echo "Please download version 4.3.28 from"
-	@echo "  http://downloads.sleepycat.com/db-4.3.28.NC.tar.gz"
+	@echo "Please download version 4.4.16 from"
+	@echo "  http://downloads.sleepycat.com/db-4.4.16.NC.tar.gz"
 	@echo "and place it in the externals/ directory."
 	false
 

src/libstore/db.cc

@@ -306,11 +306,13 @@ void Database::open(const string & path)
 
             /* Try again. */
             open2(path, false);
+
+            /* Force a checkpoint, as per the BDB docs. */
+            env->txn_checkpoint(DB_FORCE, 0, 0);
         }
         else
             rethrow(e);
     }
-    
 }