diff --git a/mozilla/toolkit/components/places/src/nsNavHistory.cpp b/mozilla/toolkit/components/places/src/nsNavHistory.cpp
index d6df0e9fee6..2ebaa7c9955 100644
--- a/mozilla/toolkit/components/places/src/nsNavHistory.cpp
+++ b/mozilla/toolkit/components/places/src/nsNavHistory.cpp
@@ -636,6 +636,12 @@ nsNavHistory::InitDB(PRInt16 *aMadeChanges)
   rv = mDBConn->ExecuteSimpleSQL(pageSizePragma);
   NS_ENSURE_SUCCESS(rv, rv);
 
+#ifdef IN_MEMORY_SQLITE_TEMP_STORE
+  rv = mDBConn->ExecuteSimpleSQL(NS_LITERAL_CSTRING(
+      "PRAGMA temp_store = MEMORY"));
+  NS_ENSURE_SUCCESS(rv, rv);
+#endif
+
   mozStorageTransaction transaction(mDBConn, PR_FALSE);
 
   // Initialize the other places services' database tables. We do this before
diff --git a/mozilla/toolkit/components/places/src/nsNavHistory.h b/mozilla/toolkit/components/places/src/nsNavHistory.h
index 52eb5cf89f0..e6c6e16a7d0 100644
--- a/mozilla/toolkit/components/places/src/nsNavHistory.h
+++ b/mozilla/toolkit/components/places/src/nsNavHistory.h
@@ -91,6 +91,9 @@
 // set to use more optimized (in-memory database) link coloring
 //#define IN_MEMORY_LINKS
 
+// define to maintain sqlite temporary tables in memory rather than on disk
+#define IN_MEMORY_SQLITE_TEMP_STORE
+
 // define to enable lazy link adding
 #define LAZY_ADD