diff --git a/pkgs/servers/sql/postgresql/8.4.x.nix b/pkgs/servers/sql/postgresql/8.4.x.nix
index 66933f2ad42..0254bbe951d 100644
--- a/pkgs/servers/sql/postgresql/8.4.x.nix
+++ b/pkgs/servers/sql/postgresql/8.4.x.nix
@@ -1,7 +1,8 @@
 { callPackage, fetchurl, ... } @ args:
 
 callPackage ./generic.nix (args // rec {
-  version = "8.4.22";
+  psqlSchema = "8.4";
+  version = "${psqlSchema}.22";
 
   src = fetchurl {
     url = "mirror://postgresql/source/v${version}/postgresql-${version}.tar.bz2";
diff --git a/pkgs/servers/sql/postgresql/9.0.x.nix b/pkgs/servers/sql/postgresql/9.0.x.nix
index 6c24e6aa4c4..dba42e4fb11 100644
--- a/pkgs/servers/sql/postgresql/9.0.x.nix
+++ b/pkgs/servers/sql/postgresql/9.0.x.nix
@@ -1,7 +1,8 @@
 { callPackage, fetchurl, ... } @ args:
 
 callPackage ./generic.nix (args // rec {
-  version = "9.0.20";
+  psqlSchema = "9.0";
+  version = "${psqlSchema}.20";
 
   src = fetchurl {
     url = "mirror://postgresql/source/v${version}/postgresql-${version}.tar.bz2";
diff --git a/pkgs/servers/sql/postgresql/9.1.x.nix b/pkgs/servers/sql/postgresql/9.1.x.nix
index b481f292ec5..138bc4a3023 100644
--- a/pkgs/servers/sql/postgresql/9.1.x.nix
+++ b/pkgs/servers/sql/postgresql/9.1.x.nix
@@ -1,7 +1,8 @@
 { callPackage, fetchurl, ... } @ args:
 
 callPackage ./generic.nix (args // rec {
-  version = "9.1.16";
+  psqlSchema = "9.1";
+  version = "${psqlSchema}.16";
 
   src = fetchurl {
     url = "mirror://postgresql/source/v${version}/postgresql-${version}.tar.bz2";
diff --git a/pkgs/servers/sql/postgresql/generic.nix b/pkgs/servers/sql/postgresql/generic.nix
index 06e6d1e79d6..721a3b6323f 100644
--- a/pkgs/servers/sql/postgresql/generic.nix
+++ b/pkgs/servers/sql/postgresql/generic.nix
@@ -10,7 +10,7 @@
 , walBlockSizeKB ? 8, walSegmentSizeMB ? 16
 
 # Version specific arguments
-, version, src
+, version, src, psqlSchema
 , ...
 }:
 
@@ -90,5 +90,7 @@ stdenv.mkDerivation rec {
     hydraPlatforms = platforms.linux;
   };
 
-  passthru = { inherit readline; };
+  passthru = {
+    inherit readline psqlSchema;
+  };
 }