diff --git a/mighttpd2.cabal b/mighttpd2.cabal
--- a/mighttpd2.cabal
+++ b/mighttpd2.cabal
@@ -1,5 +1,5 @@
 Name:                   mighttpd2
-Version:                3.4.4
+Version:                3.4.5
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -56,6 +56,8 @@
                       , wai >= 3.2 && < 3.3
                       , wai-app-file-cgi >= 3.1.1 && < 3.2
                       , warp >= 3.2.21 && < 3.3
+  if impl(ghc >= 8)
+    Default-Extensions:  Strict StrictData
 
 Executable mighty
   Default-Language:     Haskell2010
@@ -90,6 +92,8 @@
   Other-Modules:        Server
                         WaiApp
                         Paths_mighttpd2
+  if impl(ghc >= 8)
+    Default-Extensions:  Strict StrictData
 
 Executable mighty-mkindex
   Default-Language:     Haskell2010
@@ -110,6 +114,8 @@
   Build-Depends:        base >= 4 && < 5
                       , unix
                       , mighttpd2
+  if impl(ghc >= 8)
+    Default-Extensions:  Strict StrictData
 
 Test-Suite spec
   Default-Language:     Haskell2010
@@ -125,6 +131,8 @@
   if flag(tls)
     Build-Depends:      tls
                       , warp-tls >= 3.2 && < 3.3
+  if impl(ghc >= 8)
+    Default-Extensions:  Strict StrictData
 
 Source-Repository head
   Type:                 git
diff --git a/src/Server.hs b/src/Server.hs
--- a/src/Server.hs
+++ b/src/Server.hs
@@ -142,7 +142,7 @@
                 key  <- BS.readFile $ opt_tls_key_file _opt
                 let settings0 = tlsSettingsChainMemory cert chains key
                     settings = settings0 {
-                        tlsSessionManagerConfig = Just defaultConfig
+                        tlsSessionManagerConfig = Just defaultConfig { dbMaxSize = 1000 }
                       }
                 return settings
 #else