Index: src/pager.c
==================================================================
--- src/pager.c
+++ src/pager.c
@@ -4476,19 +4476,20 @@
 /*
 ** Flush all unreferenced dirty pages to disk.
 */
 int sqlite3PagerFlush(Pager *pPager){
   int rc = pPager->errCode;
-  PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
-
-  assert( assert_pager_state(pPager) );
-  while( rc==SQLITE_OK && pList ){
-    PgHdr *pNext = pList->pDirty;
-    if( pList->nRef==0 ){
-      rc = pagerStress((void*)pPager, pList);
-    }
-    pList = pNext;
+  if( !MEMDB ){
+    PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
+    assert( assert_pager_state(pPager) );
+    while( rc==SQLITE_OK && pList ){
+      PgHdr *pNext = pList->pDirty;
+      if( pList->nRef==0 ){
+        rc = pagerStress((void*)pPager, pList);
+      }
+      pList = pNext;
+    }
   }
 
   return rc;
 }