--- a/include/urweb/types_cpp.h	Thu Nov 12 10:06:07 2015 -0500
+++ b/include/urweb/types_cpp.h	Thu Nov 12 11:44:21 2015 -0500
@@ -129,15 +129,11 @@
   unsigned long timeValid;
 } uw_Sqlcache_Value;
 
-typedef struct uw_Sqlcache_Entry {
-  char *key;
-  uw_Sqlcache_Value *value;
-  unsigned long timeInvalid;
-  UT_hash_handle hh;
-} uw_Sqlcache_Entry;
+typedef struct uw_Sqlcache_Entry uw_Sqlcache_Entry;
 
 typedef struct uw_Sqlcache_Cache {
-  struct uw_Sqlcache_Entry *table;
+  //pthread_rwlock_t *lock;
+  uw_Sqlcache_Entry *table;
   unsigned long timeInvalid;
   unsigned long timeNow;
   size_t numKeys;

--- a/include/urweb/urweb_cpp.h	Thu Nov 12 10:06:07 2015 -0500
+++ b/include/urweb/urweb_cpp.h	Thu Nov 12 11:44:21 2015 -0500
@@ -408,6 +408,6 @@
 
 uw_Sqlcache_Value *uw_Sqlcache_check(uw_Sqlcache_Cache *, char **);
 void *uw_Sqlcache_store(uw_Sqlcache_Cache *, char **, uw_Sqlcache_Value *);
-void *uw_Sqlcache_flush(uw_Sqlcache_Cache *, char **);
+void *uw_Sqlcache_flush(struct uw_context *, uw_Sqlcache_Cache *, char **);
 
 #endif

--- a/src/c/urweb.c	Thu Nov 12 10:06:07 2015 -0500
+++ b/src/c/urweb.c	Thu Nov 12 11:44:21 2015 -0500
@@ -4545,6 +4545,13 @@
 
 // Sqlcache
 
+typedef struct uw_Sqlcache_Entry {
+  char *key;
+  uw_Sqlcache_Value *value;
+  unsigned long timeInvalid;
+  UT_hash_handle hh;
+} uw_Sqlcache_Entry;
+
 void uw_Sqlcache_freeValue(uw_Sqlcache_Value *value) {
   if (value) {
     free(value->result);
@@ -4599,7 +4606,7 @@
 
 char uw_Sqlcache_keySep = '_';
 
-char *uw_Sqlcache_allocKeyBuffer(char **keys, int numKeys) {
+char *uw_Sqlcache_allocKeyBuffer(char **keys, size_t numKeys) {
   size_t len = 0;
   while (numKeys-- > 0) {
     char* k = keys[numKeys];
@@ -4625,6 +4632,7 @@
 // TODO: strlen(key) = buf - key?
 
 uw_Sqlcache_Value *uw_Sqlcache_check(uw_Sqlcache_Cache *cache, char **keys) {
+  //pthread_rwlock_rdlock(cache->lock);
   size_t numKeys = cache->numKeys;
   char *key = uw_Sqlcache_allocKeyBuffer(keys, numKeys);
   char *buf = key;
@@ -4642,10 +4650,12 @@
   }
   free(key);
   uw_Sqlcache_Value *value = entry->value;
+  //pthread_rwlock_unlock(cache->lock);
   return value && value->timeValid > timeInvalid ? value : NULL;
 }
 
 void uw_Sqlcache_store(uw_Sqlcache_Cache *cache, char **keys, uw_Sqlcache_Value *value) {
+  //pthread_rwlock_wrlock(cache->lock);
   size_t numKeys = cache->numKeys;
   char *key = uw_Sqlcache_allocKeyBuffer(keys, numKeys);
   char *buf = key;
@@ -4667,6 +4677,7 @@
   uw_Sqlcache_freeValue(entry->value);
   entry->value = value;
   entry->value->timeValid = timeNow;
+  //pthread_rwlock_unlock(cache->lock);
 }
 
 void uw_Sqlcache_flushCommitOne(uw_Sqlcache_Cache *cache, char **keys) {
@@ -4717,20 +4728,28 @@
 
 void uw_Sqlcache_flushCommit(void *data) {
   uw_Sqlcache_Inval *inval = (uw_Sqlcache_Inval *)data;
-  uw_Sqlcache_Inval *invalFirst = inval;
   while (inval) {
     uw_Sqlcache_Cache *cache = inval->cache;
     char **keys = inval->keys;
     uw_Sqlcache_flushCommitOne(cache, keys);
     inval = inval->next;
   }
-  uw_Sqlcache_flushFree(invalFirst, 0);
+}
+
+char **uw_Sqlcache_copyKeys(char **keys, size_t numKeys) {
+  char **copy = malloc(sizeof(char *) * numKeys);
+  while (numKeys-- > 0) {
+    char * k = keys[numKeys];
+    copy[numKeys] = k ? strdup(k) : NULL;
+  }
+  return copy;
 }
 
 void uw_Sqlcache_flush(uw_context ctx, uw_Sqlcache_Cache *cache, char **keys) {
+  //pthread_rwlock_wrlock(cache->lock);
   uw_Sqlcache_Inval *inval = malloc(sizeof(uw_Sqlcache_Inval));
   inval->cache = cache;
-  inval->keys = keys;
+  inval->keys = uw_Sqlcache_copyKeys(keys, cache->numKeys);
   inval->next = NULL;
   if (ctx->inval) {
     // An invalidation is already registered, so just extend it.
@@ -4740,4 +4759,5 @@
   }
   // [ctx->inval] should always point to the last invalidation.
   ctx->inval = inval;
-}
+  //pthread_rwlock_unlock(cache->lock);
+}

--- a/src/lru_cache.sml	Thu Nov 12 10:06:07 2015 -0500
+++ b/src/lru_cache.sml	Thu Nov 12 11:44:21 2015 -0500
@@ -65,6 +65,8 @@
     in
         Print.box
             [string ("static uw_Sqlcache_Cache cacheStruct" ^ i ^ " = {"),
+             (* newline, *)
+             (* string "  .lock = PTHREAD_RWLOCK_INITIALIZER,", *)
              newline,
              string "  .table = NULL,",
              newline,
@@ -134,7 +136,7 @@
              newline,
              string ("  char *ks[] = {" ^ revArgs ^ "};"),
              newline,
-             string ("  uw_Sqlcache_flush(cache" ^ i ^ ", ks);"),
+             string ("  uw_Sqlcache_flush(ctx, cache" ^ i ^ ", ks);"),
              newline,
              string "  return uw_unit_v;",
              newline,