Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -2496,11 +2496,11 @@
   db->magic = SQLITE_MAGIC_BUSY;
   db->aDb = db->aDbStatic;
 
   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
-  db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = 0;
+  db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
   db->autoCommit = 1;
   db->nextAutovac = -1;
   db->szMmap = sqlite3GlobalConfig.szMmap;
   db->nextPagesize = 0;
   db->nMaxSorterMmap = 0x7FFFFFFF;

Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -437,16 +437,16 @@
 /*
 ** If no value has been provided for SQLITE_MAX_WORKER_THREADS, or if
 ** SQLITE_TEMP_STORE is set to 3 (never use temporary files), set it 
 ** to zero.
 */
-#if SQLITE_TEMP_STORE==3
+#if SQLITE_TEMP_STORE==3 || SQLITE_THREADSAFE==0
 # undef SQLITE_MAX_WORKER_THREADS
 # define SQLITE_MAX_WORKER_THREADS 0
 #endif
 #ifndef SQLITE_MAX_WORKER_THREADS
-# define SQLITE_MAX_WORKER_THREADS 4
+# define SQLITE_MAX_WORKER_THREADS 8
 #endif
 #ifndef SQLITE_DEFAULT_WORKER_THREADS
 # define SQLITE_DEFAULT_WORKER_THREADS 0
 #endif
 #if SQLITE_DEFAULT_WORKER_THREADS>SQLITE_MAX_WORKER_THREADS