changeset 2234:2f7ed04332a0

Progress on LRU cache but still more known bugs to fix.
author Ziv Scully <ziv@mit.edu>
date Sun, 28 Jun 2015 12:46:51 -0700 (2015-06-28)
parents af1585e7d645
children 0aae15c2a05a
files caching-tests/test.ur include/urweb/types_cpp.h include/urweb/urweb_cpp.h include/urweb/uthash.h src/c/urweb.c src/lru_cache.sml src/sources src/sqlcache.sml
diffstat 8 files changed, 1396 insertions(+), 55 deletions(-) [+]
line wrap: on
line diff
--- a/caching-tests/test.ur	Wed May 06 23:11:30 2015 -0400
+++ b/caching-tests/test.ur	Sun Jun 28 12:46:51 2015 -0700
@@ -16,13 +16,24 @@
                         FROM tab
                         WHERE tab.Id = {[id]});
     (case res of
-         None => dml (INSERT INTO tab (Id, Val)
-                      VALUES ({[id]}, 0))
+         None => return () (* dml (INSERT INTO tab (Id, Val) *)
+                 (*      VALUES ({[id]}, 0)) *)
        | Some row => dml (UPDATE tab
                           SET Val = {[row.Tab.Val + 1]}
-                          WHERE Id = {[id]}));
+                          WHERE Id = {[id + 1]} OR Id = {[id]} (* OR Id = {[id - 1]} *)));
     return <xml><body>
       {case res of
            None => <xml>Initialized {[id]}!</xml>
          | Some row => <xml>Incremented {[id]}!</xml>}
     </body></xml>
+
+(* task periodic 5 = *)
+(*  fn () => *)
+(*     t <- now; *)
+(*     let *)
+(*         val n = toSeconds t % 2 *)
+(*     in *)
+(*         dml (UPDATE tab *)
+(*              SET Val = 9001 *)
+(*              WHERE Id = {[n]} OR Id = {[n+1]}) *)
+(*     end *)
--- a/include/urweb/types_cpp.h	Wed May 06 23:11:30 2015 -0400
+++ b/include/urweb/types_cpp.h	Sun Jun 28 12:46:51 2015 -0700
@@ -119,4 +119,35 @@
   char *start, *front, *back;
 } uw_buffer;
 
+// Caching
+
+#include "uthash.h"
+
+typedef struct CacheValue {
+  char *result;
+  char *output;
+} CacheValue;
+
+typedef struct CacheEntry {
+  char *key;
+  void *value;
+  time_t timeValid;
+  struct CacheEntry *prev;
+  struct CacheEntry *next;
+  UT_hash_handle hh;
+} CacheEntry;
+
+typedef struct CacheList {
+  CacheEntry *first;
+  CacheEntry *last;
+  int size;
+} CacheList;
+
+typedef struct Cache {
+  CacheEntry *table;
+  time_t timeInvalid;
+  CacheList *lru;
+  int height;
+} Cache;
+
 #endif
--- a/include/urweb/urweb_cpp.h	Wed May 06 23:11:30 2015 -0400
+++ b/include/urweb/urweb_cpp.h	Sun Jun 28 12:46:51 2015 -0700
@@ -402,4 +402,12 @@
 
 void uw_Basis_writec(struct uw_context *, char);
 
+// Sqlcache.
+
+#include "uthash.h"
+
+CacheValue *check(Cache *, char **);
+CacheValue *store(Cache *, char **, CacheValue *);
+CacheValue *flush(Cache *, char **);
+
 #endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/urweb/uthash.h	Sun Jun 28 12:46:51 2015 -0700
@@ -0,0 +1,963 @@
+/*
+Copyright (c) 2003-2014, Troy D. Hanson     http://troydhanson.github.com/uthash/
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef UTHASH_H
+#define UTHASH_H
+
+#include <string.h>   /* memcmp,strlen */
+#include <stddef.h>   /* ptrdiff_t */
+#include <stdlib.h>   /* exit() */
+
+/* These macros use decltype or the earlier __typeof GNU extension.
+   As decltype is only available in newer compilers (VS2010 or gcc 4.3+
+   when compiling c++ source) this code uses whatever method is needed
+   or, for VS2008 where neither is available, uses casting workarounds. */
+#if defined(_MSC_VER)   /* MS compiler */
+#if _MSC_VER >= 1600 && defined(__cplusplus)  /* VS2010 or newer in C++ mode */
+#define DECLTYPE(x) (decltype(x))
+#else                   /* VS2008 or older (or VS2010 in C mode) */
+#define NO_DECLTYPE
+#define DECLTYPE(x)
+#endif
+#elif defined(__BORLANDC__) || defined(__LCC__) || defined(__WATCOMC__)
+#define NO_DECLTYPE
+#define DECLTYPE(x)
+#else                   /* GNU, Sun and other compilers */
+#define DECLTYPE(x) (__typeof(x))
+#endif
+
+#ifdef NO_DECLTYPE
+#define DECLTYPE_ASSIGN(dst,src)                                                 \
+do {                                                                             \
+  char **_da_dst = (char**)(&(dst));                                             \
+  *_da_dst = (char*)(src);                                                       \
+} while(0)
+#else
+#define DECLTYPE_ASSIGN(dst,src)                                                 \
+do {                                                                             \
+  (dst) = DECLTYPE(dst)(src);                                                    \
+} while(0)
+#endif
+
+/* a number of the hash function use uint32_t which isn't defined on Pre VS2010 */
+#if defined (_WIN32)
+#if defined(_MSC_VER) && _MSC_VER >= 1600
+#include <stdint.h>
+#elif defined(__WATCOMC__)
+#include <stdint.h>
+#else
+typedef unsigned int uint32_t;
+typedef unsigned char uint8_t;
+#endif
+#else
+#include <stdint.h>
+#endif
+
+#define UTHASH_VERSION 1.9.9
+
+#ifndef uthash_fatal
+#define uthash_fatal(msg) exit(-1)        /* fatal error (out of memory,etc) */
+#endif
+#ifndef uthash_malloc
+#define uthash_malloc(sz) malloc(sz)      /* malloc fcn                      */
+#endif
+#ifndef uthash_free
+#define uthash_free(ptr,sz) free(ptr)     /* free fcn                        */
+#endif
+
+#ifndef uthash_noexpand_fyi
+#define uthash_noexpand_fyi(tbl)          /* can be defined to log noexpand  */
+#endif
+#ifndef uthash_expand_fyi
+#define uthash_expand_fyi(tbl)            /* can be defined to log expands   */
+#endif
+
+/* initial number of buckets */
+#define HASH_INITIAL_NUM_BUCKETS 32U     /* initial number of buckets        */
+#define HASH_INITIAL_NUM_BUCKETS_LOG2 5U /* lg2 of initial number of buckets */
+#define HASH_BKT_CAPACITY_THRESH 10U     /* expand when bucket count reaches */
+
+/* calculate the element whose hash handle address is hhe */
+#define ELMT_FROM_HH(tbl,hhp) ((void*)(((char*)(hhp)) - ((tbl)->hho)))
+
+#define HASH_FIND(hh,head,keyptr,keylen,out)                                     \
+do {                                                                             \
+  out=NULL;                                                                      \
+  if (head != NULL) {                                                            \
+     unsigned _hf_bkt,_hf_hashv;                                                 \
+     HASH_FCN(keyptr,keylen, (head)->hh.tbl->num_buckets, _hf_hashv, _hf_bkt);   \
+     if (HASH_BLOOM_TEST((head)->hh.tbl, _hf_hashv) != 0) {                      \
+       HASH_FIND_IN_BKT((head)->hh.tbl, hh, (head)->hh.tbl->buckets[ _hf_bkt ],  \
+                        keyptr,keylen,out);                                      \
+     }                                                                           \
+  }                                                                              \
+} while (0)
+
+#ifdef HASH_BLOOM
+#define HASH_BLOOM_BITLEN (1UL << HASH_BLOOM)
+#define HASH_BLOOM_BYTELEN (HASH_BLOOM_BITLEN/8UL) + (((HASH_BLOOM_BITLEN%8UL)!=0UL) ? 1UL : 0UL)
+#define HASH_BLOOM_MAKE(tbl)                                                     \
+do {                                                                             \
+  (tbl)->bloom_nbits = HASH_BLOOM;                                               \
+  (tbl)->bloom_bv = (uint8_t*)uthash_malloc(HASH_BLOOM_BYTELEN);                 \
+  if (!((tbl)->bloom_bv))  { uthash_fatal( "out of memory"); }                   \
+  memset((tbl)->bloom_bv, 0, HASH_BLOOM_BYTELEN);                                \
+  (tbl)->bloom_sig = HASH_BLOOM_SIGNATURE;                                       \
+} while (0)
+
+#define HASH_BLOOM_FREE(tbl)                                                     \
+do {                                                                             \
+  uthash_free((tbl)->bloom_bv, HASH_BLOOM_BYTELEN);                              \
+} while (0)
+
+#define HASH_BLOOM_BITSET(bv,idx) (bv[(idx)/8U] |= (1U << ((idx)%8U)))
+#define HASH_BLOOM_BITTEST(bv,idx) (bv[(idx)/8U] & (1U << ((idx)%8U)))
+
+#define HASH_BLOOM_ADD(tbl,hashv)                                                \
+  HASH_BLOOM_BITSET((tbl)->bloom_bv, (hashv & (uint32_t)((1ULL << (tbl)->bloom_nbits) - 1U)))
+
+#define HASH_BLOOM_TEST(tbl,hashv)                                               \
+  HASH_BLOOM_BITTEST((tbl)->bloom_bv, (hashv & (uint32_t)((1ULL << (tbl)->bloom_nbits) - 1U)))
+
+#else
+#define HASH_BLOOM_MAKE(tbl)
+#define HASH_BLOOM_FREE(tbl)
+#define HASH_BLOOM_ADD(tbl,hashv)
+#define HASH_BLOOM_TEST(tbl,hashv) (1)
+#define HASH_BLOOM_BYTELEN 0U
+#endif
+
+#define HASH_MAKE_TABLE(hh,head)                                                 \
+do {                                                                             \
+  (head)->hh.tbl = (UT_hash_table*)uthash_malloc(                                \
+                  sizeof(UT_hash_table));                                        \
+  if (!((head)->hh.tbl))  { uthash_fatal( "out of memory"); }                    \
+  memset((head)->hh.tbl, 0, sizeof(UT_hash_table));                              \
+  (head)->hh.tbl->tail = &((head)->hh);                                          \
+  (head)->hh.tbl->num_buckets = HASH_INITIAL_NUM_BUCKETS;                        \
+  (head)->hh.tbl->log2_num_buckets = HASH_INITIAL_NUM_BUCKETS_LOG2;              \
+  (head)->hh.tbl->hho = (char*)(&(head)->hh) - (char*)(head);                    \
+  (head)->hh.tbl->buckets = (UT_hash_bucket*)uthash_malloc(                      \
+          HASH_INITIAL_NUM_BUCKETS*sizeof(struct UT_hash_bucket));               \
+  if (! (head)->hh.tbl->buckets) { uthash_fatal( "out of memory"); }             \
+  memset((head)->hh.tbl->buckets, 0,                                             \
+          HASH_INITIAL_NUM_BUCKETS*sizeof(struct UT_hash_bucket));               \
+  HASH_BLOOM_MAKE((head)->hh.tbl);                                               \
+  (head)->hh.tbl->signature = HASH_SIGNATURE;                                    \
+} while(0)
+
+#define HASH_ADD(hh,head,fieldname,keylen_in,add)                                \
+        HASH_ADD_KEYPTR(hh,head,&((add)->fieldname),keylen_in,add)
+
+#define HASH_REPLACE(hh,head,fieldname,keylen_in,add,replaced)                   \
+do {                                                                             \
+  replaced=NULL;                                                                 \
+  HASH_FIND(hh,head,&((add)->fieldname),keylen_in,replaced);                     \
+  if (replaced!=NULL) {                                                          \
+     HASH_DELETE(hh,head,replaced);                                              \
+  }                                                                              \
+  HASH_ADD(hh,head,fieldname,keylen_in,add);                                     \
+} while(0)
+
+#define HASH_ADD_KEYPTR(hh,head,keyptr,keylen_in,add)                            \
+do {                                                                             \
+ unsigned _ha_bkt;                                                               \
+ (add)->hh.next = NULL;                                                          \
+ (add)->hh.key = (char*)(keyptr);                                                \
+ (add)->hh.keylen = (unsigned)(keylen_in);                                       \
+ if (!(head)) {                                                                  \
+    head = (add);                                                                \
+    (head)->hh.prev = NULL;                                                      \
+    HASH_MAKE_TABLE(hh,head);                                                    \
+ } else {                                                                        \
+    (head)->hh.tbl->tail->next = (add);                                          \
+    (add)->hh.prev = ELMT_FROM_HH((head)->hh.tbl, (head)->hh.tbl->tail);         \
+    (head)->hh.tbl->tail = &((add)->hh);                                         \
+ }                                                                               \
+ (head)->hh.tbl->num_items++;                                                    \
+ (add)->hh.tbl = (head)->hh.tbl;                                                 \
+ HASH_FCN(keyptr,keylen_in, (head)->hh.tbl->num_buckets,                         \
+         (add)->hh.hashv, _ha_bkt);                                              \
+ HASH_ADD_TO_BKT((head)->hh.tbl->buckets[_ha_bkt],&(add)->hh);                   \
+ HASH_BLOOM_ADD((head)->hh.tbl,(add)->hh.hashv);                                 \
+ HASH_EMIT_KEY(hh,head,keyptr,keylen_in);                                        \
+ HASH_FSCK(hh,head);                                                             \
+} while(0)
+
+#define HASH_TO_BKT( hashv, num_bkts, bkt )                                      \
+do {                                                                             \
+  bkt = ((hashv) & ((num_bkts) - 1U));                                           \
+} while(0)
+
+/* delete "delptr" from the hash table.
+ * "the usual" patch-up process for the app-order doubly-linked-list.
+ * The use of _hd_hh_del below deserves special explanation.
+ * These used to be expressed using (delptr) but that led to a bug
+ * if someone used the same symbol for the head and deletee, like
+ *  HASH_DELETE(hh,users,users);
+ * We want that to work, but by changing the head (users) below
+ * we were forfeiting our ability to further refer to the deletee (users)
+ * in the patch-up process. Solution: use scratch space to
+ * copy the deletee pointer, then the latter references are via that
+ * scratch pointer rather than through the repointed (users) symbol.
+ */
+#define HASH_DELETE(hh,head,delptr)                                              \
+do {                                                                             \
+    struct UT_hash_handle *_hd_hh_del;                                           \
+    if ( ((delptr)->hh.prev == NULL) && ((delptr)->hh.next == NULL) )  {         \
+        uthash_free((head)->hh.tbl->buckets,                                     \
+                    (head)->hh.tbl->num_buckets*sizeof(struct UT_hash_bucket) ); \
+        HASH_BLOOM_FREE((head)->hh.tbl);                                         \
+        uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                      \
+        head = NULL;                                                             \
+    } else {                                                                     \
+        unsigned _hd_bkt;                                                        \
+        _hd_hh_del = &((delptr)->hh);                                            \
+        if ((delptr) == ELMT_FROM_HH((head)->hh.tbl,(head)->hh.tbl->tail)) {     \
+            (head)->hh.tbl->tail =                                               \
+                (UT_hash_handle*)((ptrdiff_t)((delptr)->hh.prev) +               \
+                (head)->hh.tbl->hho);                                            \
+        }                                                                        \
+        if ((delptr)->hh.prev != NULL) {                                         \
+            ((UT_hash_handle*)((ptrdiff_t)((delptr)->hh.prev) +                  \
+                    (head)->hh.tbl->hho))->next = (delptr)->hh.next;             \
+        } else {                                                                 \
+            DECLTYPE_ASSIGN(head,(delptr)->hh.next);                             \
+        }                                                                        \
+        if (_hd_hh_del->next != NULL) {                                          \
+            ((UT_hash_handle*)((ptrdiff_t)_hd_hh_del->next +                     \
+                    (head)->hh.tbl->hho))->prev =                                \
+                    _hd_hh_del->prev;                                            \
+        }                                                                        \
+        HASH_TO_BKT( _hd_hh_del->hashv, (head)->hh.tbl->num_buckets, _hd_bkt);   \
+        HASH_DEL_IN_BKT(hh,(head)->hh.tbl->buckets[_hd_bkt], _hd_hh_del);        \
+        (head)->hh.tbl->num_items--;                                             \
+    }                                                                            \
+    HASH_FSCK(hh,head);                                                          \
+} while (0)
+
+
+/* convenience forms of HASH_FIND/HASH_ADD/HASH_DEL */
+#define HASH_FIND_STR(head,findstr,out)                                          \
+    HASH_FIND(hh,head,findstr,(unsigned)strlen(findstr),out)
+#define HASH_ADD_STR(head,strfield,add)                                          \
+    HASH_ADD(hh,head,strfield[0],(unsigned int)strlen(add->strfield),add)
+#define HASH_REPLACE_STR(head,strfield,add,replaced)                             \
+    HASH_REPLACE(hh,head,strfield[0],(unsigned)strlen(add->strfield),add,replaced)
+#define HASH_FIND_INT(head,findint,out)                                          \
+    HASH_FIND(hh,head,findint,sizeof(int),out)
+#define HASH_ADD_INT(head,intfield,add)                                          \
+    HASH_ADD(hh,head,intfield,sizeof(int),add)
+#define HASH_REPLACE_INT(head,intfield,add,replaced)                             \
+    HASH_REPLACE(hh,head,intfield,sizeof(int),add,replaced)
+#define HASH_FIND_PTR(head,findptr,out)                                          \
+    HASH_FIND(hh,head,findptr,sizeof(void *),out)
+#define HASH_ADD_PTR(head,ptrfield,add)                                          \
+    HASH_ADD(hh,head,ptrfield,sizeof(void *),add)
+#define HASH_REPLACE_PTR(head,ptrfield,add,replaced)                             \
+    HASH_REPLACE(hh,head,ptrfield,sizeof(void *),add,replaced)
+#define HASH_DEL(head,delptr)                                                    \
+    HASH_DELETE(hh,head,delptr)
+
+/* HASH_FSCK checks hash integrity on every add/delete when HASH_DEBUG is defined.
+ * This is for uthash developer only; it compiles away if HASH_DEBUG isn't defined.
+ */
+#ifdef HASH_DEBUG
+#define HASH_OOPS(...) do { fprintf(stderr,__VA_ARGS__); exit(-1); } while (0)
+#define HASH_FSCK(hh,head)                                                       \
+do {                                                                             \
+    struct UT_hash_handle *_thh;                                                 \
+    if (head) {                                                                  \
+        unsigned _bkt_i;                                                         \
+        unsigned _count;                                                         \
+        char *_prev;                                                             \
+        _count = 0;                                                              \
+        for( _bkt_i = 0; _bkt_i < (head)->hh.tbl->num_buckets; _bkt_i++) {       \
+            unsigned _bkt_count = 0;                                             \
+            _thh = (head)->hh.tbl->buckets[_bkt_i].hh_head;                      \
+            _prev = NULL;                                                        \
+            while (_thh) {                                                       \
+               if (_prev != (char*)(_thh->hh_prev)) {                            \
+                   HASH_OOPS("invalid hh_prev %p, actual %p\n",                  \
+                    _thh->hh_prev, _prev );                                      \
+               }                                                                 \
+               _bkt_count++;                                                     \
+               _prev = (char*)(_thh);                                            \
+               _thh = _thh->hh_next;                                             \
+            }                                                                    \
+            _count += _bkt_count;                                                \
+            if ((head)->hh.tbl->buckets[_bkt_i].count !=  _bkt_count) {          \
+               HASH_OOPS("invalid bucket count %u, actual %u\n",                 \
+                (head)->hh.tbl->buckets[_bkt_i].count, _bkt_count);              \
+            }                                                                    \
+        }                                                                        \
+        if (_count != (head)->hh.tbl->num_items) {                               \
+            HASH_OOPS("invalid hh item count %u, actual %u\n",                   \
+                (head)->hh.tbl->num_items, _count );                             \
+        }                                                                        \
+        /* traverse hh in app order; check next/prev integrity, count */         \
+        _count = 0;                                                              \
+        _prev = NULL;                                                            \
+        _thh =  &(head)->hh;                                                     \
+        while (_thh) {                                                           \
+           _count++;                                                             \
+           if (_prev !=(char*)(_thh->prev)) {                                    \
+              HASH_OOPS("invalid prev %p, actual %p\n",                          \
+                    _thh->prev, _prev );                                         \
+           }                                                                     \
+           _prev = (char*)ELMT_FROM_HH((head)->hh.tbl, _thh);                    \
+           _thh = ( _thh->next ?  (UT_hash_handle*)((char*)(_thh->next) +        \
+                                  (head)->hh.tbl->hho) : NULL );                 \
+        }                                                                        \
+        if (_count != (head)->hh.tbl->num_items) {                               \
+            HASH_OOPS("invalid app item count %u, actual %u\n",                  \
+                (head)->hh.tbl->num_items, _count );                             \
+        }                                                                        \
+    }                                                                            \
+} while (0)
+#else
+#define HASH_FSCK(hh,head)
+#endif
+
+/* When compiled with -DHASH_EMIT_KEYS, length-prefixed keys are emitted to
+ * the descriptor to which this macro is defined for tuning the hash function.
+ * The app can #include <unistd.h> to get the prototype for write(2). */
+#ifdef HASH_EMIT_KEYS
+#define HASH_EMIT_KEY(hh,head,keyptr,fieldlen)                                   \
+do {                                                                             \
+    unsigned _klen = fieldlen;                                                   \
+    write(HASH_EMIT_KEYS, &_klen, sizeof(_klen));                                \
+    write(HASH_EMIT_KEYS, keyptr, (unsigned long)fieldlen);                      \
+} while (0)
+#else
+#define HASH_EMIT_KEY(hh,head,keyptr,fieldlen)
+#endif
+
+/* default to Jenkin's hash unless overridden e.g. DHASH_FUNCTION=HASH_SAX */
+#ifdef HASH_FUNCTION
+#define HASH_FCN HASH_FUNCTION
+#else
+#define HASH_FCN HASH_JEN
+#endif
+
+/* The Bernstein hash function, used in Perl prior to v5.6. Note (x<<5+x)=x*33. */
+#define HASH_BER(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned _hb_keylen=(unsigned)keylen;                                          \
+  const unsigned char *_hb_key=(const unsigned char*)(key);                      \
+  (hashv) = 0;                                                                   \
+  while (_hb_keylen-- != 0U) {                                                   \
+      (hashv) = (((hashv) << 5) + (hashv)) + *_hb_key++;                         \
+  }                                                                              \
+  bkt = (hashv) & (num_bkts-1U);                                                 \
+} while (0)
+
+
+/* SAX/FNV/OAT/JEN hash functions are macro variants of those listed at
+ * http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx */
+#define HASH_SAX(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned _sx_i;                                                                \
+  const unsigned char *_hs_key=(const unsigned char*)(key);                      \
+  hashv = 0;                                                                     \
+  for(_sx_i=0; _sx_i < keylen; _sx_i++) {                                        \
+      hashv ^= (hashv << 5) + (hashv >> 2) + _hs_key[_sx_i];                     \
+  }                                                                              \
+  bkt = hashv & (num_bkts-1U);                                                   \
+} while (0)
+/* FNV-1a variation */
+#define HASH_FNV(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned _fn_i;                                                                \
+  const unsigned char *_hf_key=(const unsigned char*)(key);                      \
+  hashv = 2166136261U;                                                           \
+  for(_fn_i=0; _fn_i < keylen; _fn_i++) {                                        \
+      hashv = hashv ^ _hf_key[_fn_i];                                            \
+      hashv = hashv * 16777619U;                                                 \
+  }                                                                              \
+  bkt = hashv & (num_bkts-1U);                                                   \
+} while(0)
+
+#define HASH_OAT(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned _ho_i;                                                                \
+  const unsigned char *_ho_key=(const unsigned char*)(key);                      \
+  hashv = 0;                                                                     \
+  for(_ho_i=0; _ho_i < keylen; _ho_i++) {                                        \
+      hashv += _ho_key[_ho_i];                                                   \
+      hashv += (hashv << 10);                                                    \
+      hashv ^= (hashv >> 6);                                                     \
+  }                                                                              \
+  hashv += (hashv << 3);                                                         \
+  hashv ^= (hashv >> 11);                                                        \
+  hashv += (hashv << 15);                                                        \
+  bkt = hashv & (num_bkts-1U);                                                   \
+} while(0)
+
+#define HASH_JEN_MIX(a,b,c)                                                      \
+do {                                                                             \
+  a -= b; a -= c; a ^= ( c >> 13 );                                              \
+  b -= c; b -= a; b ^= ( a << 8 );                                               \
+  c -= a; c -= b; c ^= ( b >> 13 );                                              \
+  a -= b; a -= c; a ^= ( c >> 12 );                                              \
+  b -= c; b -= a; b ^= ( a << 16 );                                              \
+  c -= a; c -= b; c ^= ( b >> 5 );                                               \
+  a -= b; a -= c; a ^= ( c >> 3 );                                               \
+  b -= c; b -= a; b ^= ( a << 10 );                                              \
+  c -= a; c -= b; c ^= ( b >> 15 );                                              \
+} while (0)
+
+#define HASH_JEN(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned _hj_i,_hj_j,_hj_k;                                                    \
+  unsigned const char *_hj_key=(unsigned const char*)(key);                      \
+  hashv = 0xfeedbeefu;                                                           \
+  _hj_i = _hj_j = 0x9e3779b9u;                                                   \
+  _hj_k = (unsigned)(keylen);                                                    \
+  while (_hj_k >= 12U) {                                                         \
+    _hj_i +=    (_hj_key[0] + ( (unsigned)_hj_key[1] << 8 )                      \
+        + ( (unsigned)_hj_key[2] << 16 )                                         \
+        + ( (unsigned)_hj_key[3] << 24 ) );                                      \
+    _hj_j +=    (_hj_key[4] + ( (unsigned)_hj_key[5] << 8 )                      \
+        + ( (unsigned)_hj_key[6] << 16 )                                         \
+        + ( (unsigned)_hj_key[7] << 24 ) );                                      \
+    hashv += (_hj_key[8] + ( (unsigned)_hj_key[9] << 8 )                         \
+        + ( (unsigned)_hj_key[10] << 16 )                                        \
+        + ( (unsigned)_hj_key[11] << 24 ) );                                     \
+                                                                                 \
+     HASH_JEN_MIX(_hj_i, _hj_j, hashv);                                          \
+                                                                                 \
+     _hj_key += 12;                                                              \
+     _hj_k -= 12U;                                                               \
+  }                                                                              \
+  hashv += (unsigned)(keylen);                                                   \
+  switch ( _hj_k ) {                                                             \
+     case 11: hashv += ( (unsigned)_hj_key[10] << 24 ); /* FALLTHROUGH */        \
+     case 10: hashv += ( (unsigned)_hj_key[9] << 16 );  /* FALLTHROUGH */        \
+     case 9:  hashv += ( (unsigned)_hj_key[8] << 8 );   /* FALLTHROUGH */        \
+     case 8:  _hj_j += ( (unsigned)_hj_key[7] << 24 );  /* FALLTHROUGH */        \
+     case 7:  _hj_j += ( (unsigned)_hj_key[6] << 16 );  /* FALLTHROUGH */        \
+     case 6:  _hj_j += ( (unsigned)_hj_key[5] << 8 );   /* FALLTHROUGH */        \
+     case 5:  _hj_j += _hj_key[4];                      /* FALLTHROUGH */        \
+     case 4:  _hj_i += ( (unsigned)_hj_key[3] << 24 );  /* FALLTHROUGH */        \
+     case 3:  _hj_i += ( (unsigned)_hj_key[2] << 16 );  /* FALLTHROUGH */        \
+     case 2:  _hj_i += ( (unsigned)_hj_key[1] << 8 );   /* FALLTHROUGH */        \
+     case 1:  _hj_i += _hj_key[0];                                               \
+  }                                                                              \
+  HASH_JEN_MIX(_hj_i, _hj_j, hashv);                                             \
+  bkt = hashv & (num_bkts-1U);                                                   \
+} while(0)
+
+/* The Paul Hsieh hash function */
+#undef get16bits
+#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__)             \
+  || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
+#define get16bits(d) (*((const uint16_t *) (d)))
+#endif
+
+#if !defined (get16bits)
+#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)             \
+                       +(uint32_t)(((const uint8_t *)(d))[0]) )
+#endif
+#define HASH_SFH(key,keylen,num_bkts,hashv,bkt)                                  \
+do {                                                                             \
+  unsigned const char *_sfh_key=(unsigned const char*)(key);                     \
+  uint32_t _sfh_tmp, _sfh_len = (uint32_t)keylen;                                \
+                                                                                 \
+  unsigned _sfh_rem = _sfh_len & 3U;                                             \
+  _sfh_len >>= 2;                                                                \
+  hashv = 0xcafebabeu;                                                           \
+                                                                                 \
+  /* Main loop */                                                                \
+  for (;_sfh_len > 0U; _sfh_len--) {                                             \
+    hashv    += get16bits (_sfh_key);                                            \
+    _sfh_tmp  = ((uint32_t)(get16bits (_sfh_key+2)) << 11) ^ hashv;              \
+    hashv     = (hashv << 16) ^ _sfh_tmp;                                        \
+    _sfh_key += 2U*sizeof (uint16_t);                                            \
+    hashv    += hashv >> 11;                                                     \
+  }                                                                              \
+                                                                                 \
+  /* Handle end cases */                                                         \
+  switch (_sfh_rem) {                                                            \
+    case 3: hashv += get16bits (_sfh_key);                                       \
+            hashv ^= hashv << 16;                                                \
+            hashv ^= (uint32_t)(_sfh_key[sizeof (uint16_t)]) << 18;              \
+            hashv += hashv >> 11;                                                \
+            break;                                                               \
+    case 2: hashv += get16bits (_sfh_key);                                       \
+            hashv ^= hashv << 11;                                                \
+            hashv += hashv >> 17;                                                \
+            break;                                                               \
+    case 1: hashv += *_sfh_key;                                                  \
+            hashv ^= hashv << 10;                                                \
+            hashv += hashv >> 1;                                                 \
+  }                                                                              \
+                                                                                 \
+    /* Force "avalanching" of final 127 bits */                                  \
+    hashv ^= hashv << 3;                                                         \
+    hashv += hashv >> 5;                                                         \
+    hashv ^= hashv << 4;                                                         \
+    hashv += hashv >> 17;                                                        \
+    hashv ^= hashv << 25;                                                        \
+    hashv += hashv >> 6;                                                         \
+    bkt = hashv & (num_bkts-1U);                                                 \
+} while(0)
+
+#ifdef HASH_USING_NO_STRICT_ALIASING
+/* The MurmurHash exploits some CPU's (x86,x86_64) tolerance for unaligned reads.
+ * For other types of CPU's (e.g. Sparc) an unaligned read causes a bus error.
+ * MurmurHash uses the faster approach only on CPU's where we know it's safe.
+ *
+ * Note the preprocessor built-in defines can be emitted using:
+ *
+ *   gcc -m64 -dM -E - < /dev/null                  (on gcc)
+ *   cc -## a.c (where a.c is a simple test file)   (Sun Studio)
+ */
+#if (defined(__i386__) || defined(__x86_64__)  || defined(_M_IX86))
+#define MUR_GETBLOCK(p,i) p[i]
+#else /* non intel */
+#define MUR_PLUS0_ALIGNED(p) (((unsigned long)p & 3UL) == 0UL)
+#define MUR_PLUS1_ALIGNED(p) (((unsigned long)p & 3UL) == 1UL)
+#define MUR_PLUS2_ALIGNED(p) (((unsigned long)p & 3UL) == 2UL)
+#define MUR_PLUS3_ALIGNED(p) (((unsigned long)p & 3UL) == 3UL)
+#define WP(p) ((uint32_t*)((unsigned long)(p) & ~3UL))
+#if (defined(__BIG_ENDIAN__) || defined(SPARC) || defined(__ppc__) || defined(__ppc64__))
+#define MUR_THREE_ONE(p) ((((*WP(p))&0x00ffffff) << 8) | (((*(WP(p)+1))&0xff000000) >> 24))
+#define MUR_TWO_TWO(p)   ((((*WP(p))&0x0000ffff) <<16) | (((*(WP(p)+1))&0xffff0000) >> 16))
+#define MUR_ONE_THREE(p) ((((*WP(p))&0x000000ff) <<24) | (((*(WP(p)+1))&0xffffff00) >>  8))
+#else /* assume little endian non-intel */
+#define MUR_THREE_ONE(p) ((((*WP(p))&0xffffff00) >> 8) | (((*(WP(p)+1))&0x000000ff) << 24))
+#define MUR_TWO_TWO(p)   ((((*WP(p))&0xffff0000) >>16) | (((*(WP(p)+1))&0x0000ffff) << 16))
+#define MUR_ONE_THREE(p) ((((*WP(p))&0xff000000) >>24) | (((*(WP(p)+1))&0x00ffffff) <<  8))
+#endif
+#define MUR_GETBLOCK(p,i) (MUR_PLUS0_ALIGNED(p) ? ((p)[i]) :           \
+                            (MUR_PLUS1_ALIGNED(p) ? MUR_THREE_ONE(p) : \
+                             (MUR_PLUS2_ALIGNED(p) ? MUR_TWO_TWO(p) :  \
+                                                      MUR_ONE_THREE(p))))
+#endif
+#define MUR_ROTL32(x,r) (((x) << (r)) | ((x) >> (32 - (r))))
+#define MUR_FMIX(_h) \
+do {                 \
+  _h ^= _h >> 16;    \
+  _h *= 0x85ebca6bu; \
+  _h ^= _h >> 13;    \
+  _h *= 0xc2b2ae35u; \
+  _h ^= _h >> 16;    \
+} while(0)
+
+#define HASH_MUR(key,keylen,num_bkts,hashv,bkt)                        \
+do {                                                                   \
+  const uint8_t *_mur_data = (const uint8_t*)(key);                    \
+  const int _mur_nblocks = (int)(keylen) / 4;                          \
+  uint32_t _mur_h1 = 0xf88D5353u;                                      \
+  uint32_t _mur_c1 = 0xcc9e2d51u;                                      \
+  uint32_t _mur_c2 = 0x1b873593u;                                      \
+  uint32_t _mur_k1 = 0;                                                \
+  const uint8_t *_mur_tail;                                            \
+  const uint32_t *_mur_blocks = (const uint32_t*)(_mur_data+(_mur_nblocks*4)); \
+  int _mur_i;                                                          \
+  for(_mur_i = -_mur_nblocks; _mur_i!=0; _mur_i++) {                   \
+    _mur_k1 = MUR_GETBLOCK(_mur_blocks,_mur_i);                        \
+    _mur_k1 *= _mur_c1;                                                \
+    _mur_k1 = MUR_ROTL32(_mur_k1,15);                                  \
+    _mur_k1 *= _mur_c2;                                                \
+                                                                       \
+    _mur_h1 ^= _mur_k1;                                                \
+    _mur_h1 = MUR_ROTL32(_mur_h1,13);                                  \
+    _mur_h1 = (_mur_h1*5U) + 0xe6546b64u;                              \
+  }                                                                    \
+  _mur_tail = (const uint8_t*)(_mur_data + (_mur_nblocks*4));          \
+  _mur_k1=0;                                                           \
+  switch((keylen) & 3U) {                                              \
+    case 3: _mur_k1 ^= (uint32_t)_mur_tail[2] << 16; /* FALLTHROUGH */ \
+    case 2: _mur_k1 ^= (uint32_t)_mur_tail[1] << 8;  /* FALLTHROUGH */ \
+    case 1: _mur_k1 ^= (uint32_t)_mur_tail[0];                         \
+    _mur_k1 *= _mur_c1;                                                \
+    _mur_k1 = MUR_ROTL32(_mur_k1,15);                                  \
+    _mur_k1 *= _mur_c2;                                                \
+    _mur_h1 ^= _mur_k1;                                                \
+  }                                                                    \
+  _mur_h1 ^= (uint32_t)(keylen);                                       \
+  MUR_FMIX(_mur_h1);                                                   \
+  hashv = _mur_h1;                                                     \
+  bkt = hashv & (num_bkts-1U);                                         \
+} while(0)
+#endif  /* HASH_USING_NO_STRICT_ALIASING */
+
+/* key comparison function; return 0 if keys equal */
+#define HASH_KEYCMP(a,b,len) memcmp(a,b,(unsigned long)(len))
+
+/* iterate over items in a known bucket to find desired item */
+#define HASH_FIND_IN_BKT(tbl,hh,head,keyptr,keylen_in,out)                       \
+do {                                                                             \
+ if (head.hh_head != NULL) { DECLTYPE_ASSIGN(out,ELMT_FROM_HH(tbl,head.hh_head)); } \
+ else { out=NULL; }                                                              \
+ while (out != NULL) {                                                           \
+    if ((out)->hh.keylen == (keylen_in)) {                                       \
+        if ((HASH_KEYCMP((out)->hh.key,keyptr,keylen_in)) == 0) { break; }         \
+    }                                                                            \
+    if ((out)->hh.hh_next != NULL) { DECLTYPE_ASSIGN(out,ELMT_FROM_HH(tbl,(out)->hh.hh_next)); } \
+    else { out = NULL; }                                                         \
+ }                                                                               \
+} while(0)
+
+/* add an item to a bucket  */
+#define HASH_ADD_TO_BKT(head,addhh)                                              \
+do {                                                                             \
+ head.count++;                                                                   \
+ (addhh)->hh_next = head.hh_head;                                                \
+ (addhh)->hh_prev = NULL;                                                        \
+ if (head.hh_head != NULL) { (head).hh_head->hh_prev = (addhh); }                \
+ (head).hh_head=addhh;                                                           \
+ if ((head.count >= ((head.expand_mult+1U) * HASH_BKT_CAPACITY_THRESH))          \
+     && ((addhh)->tbl->noexpand != 1U)) {                                        \
+       HASH_EXPAND_BUCKETS((addhh)->tbl);                                        \
+ }                                                                               \
+} while(0)
+
+/* remove an item from a given bucket */
+#define HASH_DEL_IN_BKT(hh,head,hh_del)                                          \
+    (head).count--;                                                              \
+    if ((head).hh_head == hh_del) {                                              \
+      (head).hh_head = hh_del->hh_next;                                          \
+    }                                                                            \
+    if (hh_del->hh_prev) {                                                       \
+        hh_del->hh_prev->hh_next = hh_del->hh_next;                              \
+    }                                                                            \
+    if (hh_del->hh_next) {                                                       \
+        hh_del->hh_next->hh_prev = hh_del->hh_prev;                              \
+    }
+
+/* Bucket expansion has the effect of doubling the number of buckets
+ * and redistributing the items into the new buckets. Ideally the
+ * items will distribute more or less evenly into the new buckets
+ * (the extent to which this is true is a measure of the quality of
+ * the hash function as it applies to the key domain).
+ *
+ * With the items distributed into more buckets, the chain length
+ * (item count) in each bucket is reduced. Thus by expanding buckets
+ * the hash keeps a bound on the chain length. This bounded chain
+ * length is the essence of how a hash provides constant time lookup.
+ *
+ * The calculation of tbl->ideal_chain_maxlen below deserves some
+ * explanation. First, keep in mind that we're calculating the ideal
+ * maximum chain length based on the *new* (doubled) bucket count.
+ * In fractions this is just n/b (n=number of items,b=new num buckets).
+ * Since the ideal chain length is an integer, we want to calculate
+ * ceil(n/b). We don't depend on floating point arithmetic in this
+ * hash, so to calculate ceil(n/b) with integers we could write
+ *
+ *      ceil(n/b) = (n/b) + ((n%b)?1:0)
+ *
+ * and in fact a previous version of this hash did just that.
+ * But now we have improved things a bit by recognizing that b is
+ * always a power of two. We keep its base 2 log handy (call it lb),
+ * so now we can write this with a bit shift and logical AND:
+ *
+ *      ceil(n/b) = (n>>lb) + ( (n & (b-1)) ? 1:0)
+ *
+ */
+#define HASH_EXPAND_BUCKETS(tbl)                                                 \
+do {                                                                             \
+    unsigned _he_bkt;                                                            \
+    unsigned _he_bkt_i;                                                          \
+    struct UT_hash_handle *_he_thh, *_he_hh_nxt;                                 \
+    UT_hash_bucket *_he_new_buckets, *_he_newbkt;                                \
+    _he_new_buckets = (UT_hash_bucket*)uthash_malloc(                            \
+             2UL * tbl->num_buckets * sizeof(struct UT_hash_bucket));            \
+    if (!_he_new_buckets) { uthash_fatal( "out of memory"); }                    \
+    memset(_he_new_buckets, 0,                                                   \
+            2UL * tbl->num_buckets * sizeof(struct UT_hash_bucket));             \
+    tbl->ideal_chain_maxlen =                                                    \
+       (tbl->num_items >> (tbl->log2_num_buckets+1U)) +                          \
+       (((tbl->num_items & ((tbl->num_buckets*2U)-1U)) != 0U) ? 1U : 0U);        \
+    tbl->nonideal_items = 0;                                                     \
+    for(_he_bkt_i = 0; _he_bkt_i < tbl->num_buckets; _he_bkt_i++)                \
+    {                                                                            \
+        _he_thh = tbl->buckets[ _he_bkt_i ].hh_head;                             \
+        while (_he_thh != NULL) {                                                \
+           _he_hh_nxt = _he_thh->hh_next;                                        \
+           HASH_TO_BKT( _he_thh->hashv, tbl->num_buckets*2U, _he_bkt);           \
+           _he_newbkt = &(_he_new_buckets[ _he_bkt ]);                           \
+           if (++(_he_newbkt->count) > tbl->ideal_chain_maxlen) {                \
+             tbl->nonideal_items++;                                              \
+             _he_newbkt->expand_mult = _he_newbkt->count /                       \
+                                        tbl->ideal_chain_maxlen;                 \
+           }                                                                     \
+           _he_thh->hh_prev = NULL;                                              \
+           _he_thh->hh_next = _he_newbkt->hh_head;                               \
+           if (_he_newbkt->hh_head != NULL) { _he_newbkt->hh_head->hh_prev =     \
+                _he_thh; }                                                       \
+           _he_newbkt->hh_head = _he_thh;                                        \
+           _he_thh = _he_hh_nxt;                                                 \
+        }                                                                        \
+    }                                                                            \
+    uthash_free( tbl->buckets, tbl->num_buckets*sizeof(struct UT_hash_bucket) ); \
+    tbl->num_buckets *= 2U;                                                      \
+    tbl->log2_num_buckets++;                                                     \
+    tbl->buckets = _he_new_buckets;                                              \
+    tbl->ineff_expands = (tbl->nonideal_items > (tbl->num_items >> 1)) ?         \
+        (tbl->ineff_expands+1U) : 0U;                                            \
+    if (tbl->ineff_expands > 1U) {                                               \
+        tbl->noexpand=1;                                                         \
+        uthash_noexpand_fyi(tbl);                                                \
+    }                                                                            \
+    uthash_expand_fyi(tbl);                                                      \
+} while(0)
+
+
+/* This is an adaptation of Simon Tatham's O(n log(n)) mergesort */
+/* Note that HASH_SORT assumes the hash handle name to be hh.
+ * HASH_SRT was added to allow the hash handle name to be passed in. */
+#define HASH_SORT(head,cmpfcn) HASH_SRT(hh,head,cmpfcn)
+#define HASH_SRT(hh,head,cmpfcn)                                                 \
+do {                                                                             \
+  unsigned _hs_i;                                                                \
+  unsigned _hs_looping,_hs_nmerges,_hs_insize,_hs_psize,_hs_qsize;               \
+  struct UT_hash_handle *_hs_p, *_hs_q, *_hs_e, *_hs_list, *_hs_tail;            \
+  if (head != NULL) {                                                            \
+      _hs_insize = 1;                                                            \
+      _hs_looping = 1;                                                           \
+      _hs_list = &((head)->hh);                                                  \
+      while (_hs_looping != 0U) {                                                \
+          _hs_p = _hs_list;                                                      \
+          _hs_list = NULL;                                                       \
+          _hs_tail = NULL;                                                       \
+          _hs_nmerges = 0;                                                       \
+          while (_hs_p != NULL) {                                                \
+              _hs_nmerges++;                                                     \
+              _hs_q = _hs_p;                                                     \
+              _hs_psize = 0;                                                     \
+              for ( _hs_i = 0; _hs_i  < _hs_insize; _hs_i++ ) {                  \
+                  _hs_psize++;                                                   \
+                  _hs_q = (UT_hash_handle*)((_hs_q->next != NULL) ?              \
+                          ((void*)((char*)(_hs_q->next) +                        \
+                          (head)->hh.tbl->hho)) : NULL);                         \
+                  if (! (_hs_q) ) { break; }                                     \
+              }                                                                  \
+              _hs_qsize = _hs_insize;                                            \
+              while ((_hs_psize > 0U) || ((_hs_qsize > 0U) && (_hs_q != NULL))) {\
+                  if (_hs_psize == 0U) {                                         \
+                      _hs_e = _hs_q;                                             \
+                      _hs_q = (UT_hash_handle*)((_hs_q->next != NULL) ?          \
+                              ((void*)((char*)(_hs_q->next) +                    \
+                              (head)->hh.tbl->hho)) : NULL);                     \
+                      _hs_qsize--;                                               \
+                  } else if ( (_hs_qsize == 0U) || (_hs_q == NULL) ) {           \
+                      _hs_e = _hs_p;                                             \
+                      if (_hs_p != NULL){                                        \
+                        _hs_p = (UT_hash_handle*)((_hs_p->next != NULL) ?        \
+                                ((void*)((char*)(_hs_p->next) +                  \
+                                (head)->hh.tbl->hho)) : NULL);                   \
+                       }                                                         \
+                      _hs_psize--;                                               \
+                  } else if ((                                                   \
+                      cmpfcn(DECLTYPE(head)(ELMT_FROM_HH((head)->hh.tbl,_hs_p)), \
+                             DECLTYPE(head)(ELMT_FROM_HH((head)->hh.tbl,_hs_q))) \
+                             ) <= 0) {                                           \
+                      _hs_e = _hs_p;                                             \
+                      if (_hs_p != NULL){                                        \
+                        _hs_p = (UT_hash_handle*)((_hs_p->next != NULL) ?        \
+                               ((void*)((char*)(_hs_p->next) +                   \
+                               (head)->hh.tbl->hho)) : NULL);                    \
+                       }                                                         \
+                      _hs_psize--;                                               \
+                  } else {                                                       \
+                      _hs_e = _hs_q;                                             \
+                      _hs_q = (UT_hash_handle*)((_hs_q->next != NULL) ?          \
+                              ((void*)((char*)(_hs_q->next) +                    \
+                              (head)->hh.tbl->hho)) : NULL);                     \
+                      _hs_qsize--;                                               \
+                  }                                                              \
+                  if ( _hs_tail != NULL ) {                                      \
+                      _hs_tail->next = ((_hs_e != NULL) ?                        \
+                            ELMT_FROM_HH((head)->hh.tbl,_hs_e) : NULL);          \
+                  } else {                                                       \
+                      _hs_list = _hs_e;                                          \
+                  }                                                              \
+                  if (_hs_e != NULL) {                                           \
+                  _hs_e->prev = ((_hs_tail != NULL) ?                            \
+                     ELMT_FROM_HH((head)->hh.tbl,_hs_tail) : NULL);              \
+                  }                                                              \
+                  _hs_tail = _hs_e;                                              \
+              }                                                                  \
+              _hs_p = _hs_q;                                                     \
+          }                                                                      \
+          if (_hs_tail != NULL){                                                 \
+            _hs_tail->next = NULL;                                               \
+          }                                                                      \
+          if ( _hs_nmerges <= 1U ) {                                             \
+              _hs_looping=0;                                                     \
+              (head)->hh.tbl->tail = _hs_tail;                                   \
+              DECLTYPE_ASSIGN(head,ELMT_FROM_HH((head)->hh.tbl, _hs_list));      \
+          }                                                                      \
+          _hs_insize *= 2U;                                                      \
+      }                                                                          \
+      HASH_FSCK(hh,head);                                                        \
+ }                                                                               \
+} while (0)
+
+/* This function selects items from one hash into another hash.
+ * The end result is that the selected items have dual presence
+ * in both hashes. There is no copy of the items made; rather
+ * they are added into the new hash through a secondary hash
+ * hash handle that must be present in the structure. */
+#define HASH_SELECT(hh_dst, dst, hh_src, src, cond)                              \
+do {                                                                             \
+  unsigned _src_bkt, _dst_bkt;                                                   \
+  void *_last_elt=NULL, *_elt;                                                   \
+  UT_hash_handle *_src_hh, *_dst_hh, *_last_elt_hh=NULL;                         \
+  ptrdiff_t _dst_hho = ((char*)(&(dst)->hh_dst) - (char*)(dst));                 \
+  if (src != NULL) {                                                             \
+    for(_src_bkt=0; _src_bkt < (src)->hh_src.tbl->num_buckets; _src_bkt++) {     \
+      for(_src_hh = (src)->hh_src.tbl->buckets[_src_bkt].hh_head;                \
+          _src_hh != NULL;                                                       \
+          _src_hh = _src_hh->hh_next) {                                          \
+          _elt = ELMT_FROM_HH((src)->hh_src.tbl, _src_hh);                       \
+          if (cond(_elt)) {                                                      \
+            _dst_hh = (UT_hash_handle*)(((char*)_elt) + _dst_hho);               \
+            _dst_hh->key = _src_hh->key;                                         \
+            _dst_hh->keylen = _src_hh->keylen;                                   \
+            _dst_hh->hashv = _src_hh->hashv;                                     \
+            _dst_hh->prev = _last_elt;                                           \
+            _dst_hh->next = NULL;                                                \
+            if (_last_elt_hh != NULL) { _last_elt_hh->next = _elt; }             \
+            if (dst == NULL) {                                                   \
+              DECLTYPE_ASSIGN(dst,_elt);                                         \
+              HASH_MAKE_TABLE(hh_dst,dst);                                       \
+            } else {                                                             \
+              _dst_hh->tbl = (dst)->hh_dst.tbl;                                  \
+            }                                                                    \
+            HASH_TO_BKT(_dst_hh->hashv, _dst_hh->tbl->num_buckets, _dst_bkt);    \
+            HASH_ADD_TO_BKT(_dst_hh->tbl->buckets[_dst_bkt],_dst_hh);            \
+            (dst)->hh_dst.tbl->num_items++;                                      \
+            _last_elt = _elt;                                                    \
+            _last_elt_hh = _dst_hh;                                              \
+          }                                                                      \
+      }                                                                          \
+    }                                                                            \
+  }                                                                              \
+  HASH_FSCK(hh_dst,dst);                                                         \
+} while (0)
+
+#define HASH_CLEAR(hh,head)                                                      \
+do {                                                                             \
+  if (head != NULL) {                                                            \
+    uthash_free((head)->hh.tbl->buckets,                                         \
+                (head)->hh.tbl->num_buckets*sizeof(struct UT_hash_bucket));      \
+    HASH_BLOOM_FREE((head)->hh.tbl);                                             \
+    uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                          \
+    (head)=NULL;                                                                 \
+  }                                                                              \
+} while(0)
+
+#define HASH_OVERHEAD(hh,head)                                                   \
+ ((head != NULL) ? (                                                             \
+ (size_t)(((head)->hh.tbl->num_items   * sizeof(UT_hash_handle))   +             \
+          ((head)->hh.tbl->num_buckets * sizeof(UT_hash_bucket))   +             \
+           sizeof(UT_hash_table)                                   +             \
+           (HASH_BLOOM_BYTELEN))) : 0U)
+
+#ifdef NO_DECLTYPE
+#define HASH_ITER(hh,head,el,tmp)                                                \
+for(((el)=(head)), ((*(char**)(&(tmp)))=(char*)((head!=NULL)?(head)->hh.next:NULL)); \
+  (el) != NULL; ((el)=(tmp)), ((*(char**)(&(tmp)))=(char*)((tmp!=NULL)?(tmp)->hh.next:NULL)))
+#else
+#define HASH_ITER(hh,head,el,tmp)                                                \
+for(((el)=(head)), ((tmp)=DECLTYPE(el)((head!=NULL)?(head)->hh.next:NULL));      \
+  (el) != NULL; ((el)=(tmp)), ((tmp)=DECLTYPE(el)((tmp!=NULL)?(tmp)->hh.next:NULL)))
+#endif
+
+/* obtain a count of items in the hash */
+#define HASH_COUNT(head) HASH_CNT(hh,head)
+#define HASH_CNT(hh,head) ((head != NULL)?((head)->hh.tbl->num_items):0U)
+
+typedef struct UT_hash_bucket {
+   struct UT_hash_handle *hh_head;
+   unsigned count;
+
+   /* expand_mult is normally set to 0. In this situation, the max chain length
+    * threshold is enforced at its default value, HASH_BKT_CAPACITY_THRESH. (If
+    * the bucket's chain exceeds this length, bucket expansion is triggered).
+    * However, setting expand_mult to a non-zero value delays bucket expansion
+    * (that would be triggered by additions to this particular bucket)
+    * until its chain length reaches a *multiple* of HASH_BKT_CAPACITY_THRESH.
+    * (The multiplier is simply expand_mult+1). The whole idea of this
+    * multiplier is to reduce bucket expansions, since they are expensive, in
+    * situations where we know that a particular bucket tends to be overused.
+    * It is better to let its chain length grow to a longer yet-still-bounded
+    * value, than to do an O(n) bucket expansion too often.
+    */
+   unsigned expand_mult;
+
+} UT_hash_bucket;
+
+/* random signature used only to find hash tables in external analysis */
+#define HASH_SIGNATURE 0xa0111fe1u
+#define HASH_BLOOM_SIGNATURE 0xb12220f2u
+
+typedef struct UT_hash_table {
+   UT_hash_bucket *buckets;
+   unsigned num_buckets, log2_num_buckets;
+   unsigned num_items;
+   struct UT_hash_handle *tail; /* tail hh in app order, for fast append    */
+   ptrdiff_t hho; /* hash handle offset (byte pos of hash handle in element */
+
+   /* in an ideal situation (all buckets used equally), no bucket would have
+    * more than ceil(#items/#buckets) items. that's the ideal chain length. */
+   unsigned ideal_chain_maxlen;
+
+   /* nonideal_items is the number of items in the hash whose chain position
+    * exceeds the ideal chain maxlen. these items pay the penalty for an uneven
+    * hash distribution; reaching them in a chain traversal takes >ideal steps */
+   unsigned nonideal_items;
+
+   /* ineffective expands occur when a bucket doubling was performed, but
+    * afterward, more than half the items in the hash had nonideal chain
+    * positions. If this happens on two consecutive expansions we inhibit any
+    * further expansion, as it's not helping; this happens when the hash
+    * function isn't a good fit for the key domain. When expansion is inhibited
+    * the hash will still work, albeit no longer in constant time. */
+   unsigned ineff_expands, noexpand;
+
+   uint32_t signature; /* used only to find hash tables in external analysis */
+#ifdef HASH_BLOOM
+   uint32_t bloom_sig; /* used only to test bloom exists in external analysis */
+   uint8_t *bloom_bv;
+   uint8_t bloom_nbits;
+#endif
+
+} UT_hash_table;
+
+typedef struct UT_hash_handle {
+   struct UT_hash_table *tbl;
+   void *prev;                       /* prev element in app order      */
+   void *next;                       /* next element in app order      */
+   struct UT_hash_handle *hh_prev;   /* previous hh in bucket order    */
+   struct UT_hash_handle *hh_next;   /* next hh in bucket order        */
+   void *key;                        /* ptr to enclosing struct's key  */
+   unsigned keylen;                  /* enclosing struct's key len     */
+   unsigned hashv;                   /* result of hash-fcn(key)        */
+} UT_hash_handle;
+
+#endif /* UTHASH_H */
--- a/src/c/urweb.c	Wed May 06 23:11:30 2015 -0400
+++ b/src/c/urweb.c	Sun Jun 28 12:46:51 2015 -0700
@@ -22,6 +22,8 @@
 
 #include "types.h"
 
+#include "uthash.h"
+
 uw_unit uw_unit_v = 0;
 
 
@@ -4494,3 +4496,148 @@
 void uw_set_remoteSock(uw_context ctx, int sock) {
   ctx->remoteSock = sock;
 }
+
+
+// Sqlcache
+
+void listDelete(CacheList *list, CacheEntry *entry) {
+  if (list->first == entry) {
+    list->first = entry->next;
+  }
+  if (list->last == entry) {
+    list->last = entry->prev;
+  }
+  if (entry->prev) {
+    entry->prev->next = entry->next;
+  }
+  if (entry->next) {
+    entry->next->prev = entry->prev;
+  }
+  entry->prev = NULL;
+  entry->next = NULL;
+  --(list->size);
+}
+
+void listAdd(CacheList *list, CacheEntry *entry) {
+  if (list->last) {
+    list->last->next = entry;
+    entry->prev = list->last;
+    list->last = entry;
+  } else {
+    list->first = entry;
+    list->last = entry;
+  }
+  ++(list->size);
+}
+
+void listBump(CacheList *list, CacheEntry *entry) {
+  listDelete(list, entry);
+  listAdd(list, entry);
+}
+
+// TODO: deal with time properly.
+
+time_t getTimeNow() {
+  return time(NULL);
+}
+
+time_t timeMax(time_t x, time_t y) {
+  return difftime(x, y) > 0 ? x : y;
+}
+
+void freeCacheValue(CacheValue *value) {
+  if (value) {
+    free(value->result);
+    free(value->output);
+    free(value);
+  }
+}
+
+void delete(Cache *cache, CacheEntry* entry) {
+  //listDelete(cache->lru, entry);
+  HASH_DELETE(hh, cache->table, entry);
+  freeCacheValue(entry->value);
+  free(entry->key);
+  free(entry);
+}
+
+CacheValue *checkHelper(Cache *cache, char **keys, int timeInvalid) {
+  char *key = keys[cache->height];
+  CacheEntry *entry;
+  HASH_FIND(hh, cache->table, key, strlen(key), entry);
+  timeInvalid = timeMax(timeInvalid, cache->timeInvalid);
+  if (entry && difftime(entry->timeValid, timeInvalid) > 0) {
+    if (cache->height == 0) {
+      // At height 0, entry->value is the desired value.
+      //listBump(cache->lru, entry);
+      return entry->value;
+    } else {
+      // At height n+1, entry->value is a pointer to a cache at heignt n.
+      return checkHelper(entry->value, keys, timeInvalid);
+    }
+  } else {
+    return NULL;
+  }
+}
+
+CacheValue *check(Cache *cache, char **keys) {
+  return checkHelper(cache, keys, 0);
+}
+
+void storeHelper(Cache *cache, char **keys, CacheValue *value, int timeNow) {
+  CacheEntry *entry;
+  char *key = keys[cache->height];
+  HASH_FIND(hh, cache->table, key, strlen(key), entry);
+  if (!entry) {
+    entry = malloc(sizeof(CacheEntry));
+    entry->key = strdup(key);
+    entry->value = NULL;
+    HASH_ADD_KEYPTR(hh, cache->table, entry->key, strlen(entry->key), entry);
+  }
+  entry->timeValid = timeNow;
+  if (cache->height == 0) {
+    //listAdd(cache->lru, entry);
+    freeCacheValue(entry->value);
+    entry->value = value;
+    //if (cache->lru->size > MAX_SIZE) {
+      //delete(cache, cache->lru->first);
+      // TODO: return flushed value.
+    //}
+  } else {
+    if (!entry->value) {
+      Cache *newCache = malloc(sizeof(Cache));
+      newCache->table = NULL;
+      newCache->timeInvalid = timeNow;
+      newCache->lru = cache->lru;
+      newCache->height = cache->height - 1;
+      entry->value = newCache;
+    }
+    storeHelper(entry->value, keys, value, timeNow);
+  }
+}
+
+void store(Cache *cache, char **keys, CacheValue *value) {
+  storeHelper(cache, keys, value, getTimeNow());
+}
+
+void flushHelper(Cache *cache, char **keys, int timeNow) {
+  CacheEntry *entry;
+  char *key = keys[cache->height];
+  if (key) {
+    HASH_FIND(hh, cache->table, key, strlen(key), entry);
+    if (entry) {
+      if (cache->height == 0) {
+        delete(cache, entry);
+      } else {
+        flushHelper(entry->value, keys, timeNow);
+      }
+    }
+  } else {
+    // Null key means invalidate the entire subtree.
+    cache->timeInvalid = timeNow;
+  }
+}
+
+void flush(Cache *cache, char **keys) {
+  flushHelper(cache, keys, getTimeNow());
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lru_cache.sml	Sun Jun 28 12:46:51 2015 -0700
@@ -0,0 +1,171 @@
+structure LruCache : sig
+    val cache : Cache.cache
+end = struct
+
+
+(* Mono *)
+
+open Mono
+
+val dummyLoc = ErrorMsg.dummySpan
+val stringTyp = (TFfi ("Basis", "string"), dummyLoc)
+val optionStringTyp = (TOption stringTyp, dummyLoc)
+fun withTyp typ = map (fn exp => (exp, typ))
+
+fun ffiAppCache' (func, index, argTyps) =
+    EFfiApp ("Sqlcache", func ^ Int.toString index, argTyps)
+
+fun check (index, keys) =
+    ffiAppCache' ("check", index, withTyp stringTyp keys)
+
+fun store (index, keys, value) =
+    ffiAppCache' ("store", index, (value, stringTyp) :: withTyp stringTyp keys)
+
+fun flush (index, keys) =
+    ffiAppCache' ("flush", index, withTyp optionStringTyp keys)
+
+
+(* Cjr *)
+
+open Print
+open Print.PD
+
+fun setupQuery {index, params} =
+    let
+
+        val i = Int.toString index
+
+        fun paramRepeat itemi sep =
+            let
+                fun f n =
+                    if n < 0 then ""
+                    else if n = 0 then itemi (Int.toString 0)
+                    else f (n-1) ^ sep ^ itemi (Int.toString n)
+            in
+                f (params - 1)
+            end
+
+        fun paramRepeatRev itemi sep =
+            let
+                fun f n =
+                    if n < 0 then ""
+                    else if n = 0 then itemi (Int.toString 0)
+                    else itemi (Int.toString n) ^ sep ^ f (n-1)
+            in
+                f (params - 1)
+            end
+
+        fun paramRepeatInit itemi sep =
+            if params = 0 then "" else sep ^ paramRepeat itemi sep
+
+        val typedArgs = paramRepeatInit (fn p => "uw_Basis_string p" ^ p) ", "
+
+        val revArgs = paramRepeatRev (fn p => "p" ^ p) ", "
+
+    in
+        Print.box
+            [string ("static Cache cacheStruct" ^ i ^ " = {"),
+             newline,
+             string "  .table = NULL,",
+             newline,
+             string "  .timeInvalid = 0,",
+             newline,
+             string "  .lru = NULL,",
+             newline,
+             string ("  .height = " ^ Int.toString (params - 1) ^ "};"),
+             newline,
+             string ("static Cache *cache" ^ i ^ " = &cacheStruct" ^ i ^ ";"),
+             newline,
+             newline,
+
+             string ("static uw_Basis_string uw_Sqlcache_check" ^ i),
+             string ("(uw_context ctx" ^ typedArgs ^ ") {"),
+             newline,
+             string ("  char *ks[] = {" ^ revArgs ^ "};"),
+             newline,
+             string ("  CacheValue *v = check(cache" ^ i ^ ", ks);"),
+             newline,
+             string "  if (v) {",
+             newline,
+             string ("    puts(\"SQLCACHE: hit " ^ i ^ ".\");"),
+             newline,
+             string "    uw_write(ctx, v->output);",
+             newline,
+             string "    return v->result;",
+             newline,
+             string "  } else {",
+             newline,
+             string ("    puts(\"SQLCACHE: miss " ^ i ^ ".\");"),
+             newline,
+             string "    uw_recordingStart(ctx);",
+             newline,
+             string "    return NULL;",
+             newline,
+             string "  }",
+             newline,
+             string "}",
+             newline,
+             newline,
+
+             string ("static uw_unit uw_Sqlcache_store" ^ i),
+             string ("(uw_context ctx, uw_Basis_string s" ^ typedArgs ^ ") {"),
+             newline,
+             string ("  char *ks[] = {" ^ revArgs ^ "};"),
+             newline,
+             string ("  CacheValue *v = malloc(sizeof(CacheValue));"),
+             newline,
+             string "  v->result = strdup(s);",
+             newline,
+             string "  v->output = uw_recordingRead(ctx);",
+             newline,
+             string ("  puts(\"SQLCACHE: stored " ^ i ^ ".\");"),
+             newline,
+             string ("  store(cache" ^ i ^ ", ks, v);"),
+             newline,
+             string "  return uw_unit_v;",
+             newline,
+             string "}",
+             newline,
+             newline,
+
+             string ("static uw_unit uw_Sqlcache_flush" ^ i),
+             string ("(uw_context ctx" ^ typedArgs ^ ") {"),
+             newline,
+             string ("  char *ks[] = {" ^ revArgs ^ "};"),
+             newline,
+             string ("  flush(cache" ^ i ^ ", ks);"),
+             newline,
+             string "  return uw_unit_v;",
+             newline,
+             string "}",
+             newline,
+             newline]
+    end
+
+val setupGlobal = string "/* No global setup for LRU cache. */"
+
+
+(* Bundled up. *)
+
+(* For now, use the toy implementation if there are no arguments. *)
+fun toyIfNoKeys numKeys implLru implToy args =
+    if numKeys args = 0
+    then implToy args
+    else implLru args
+
+val cache =
+    let
+        val {check = toyCheck,
+             store = toyStore,
+             flush = toyFlush,
+             setupQuery = toySetupQuery,
+             ...} = ToyCache.cache
+    in
+        {check = toyIfNoKeys (length o #2) check toyCheck,
+         store = toyIfNoKeys (length o #2) store toyStore,
+         flush = toyIfNoKeys (length o #2) flush toyFlush,
+         setupQuery = toyIfNoKeys #params setupQuery toySetupQuery,
+         setupGlobal = setupGlobal}
+    end
+
+end
--- a/src/sources	Wed May 06 23:11:30 2015 -0400
+++ b/src/sources	Sun Jun 28 12:46:51 2015 -0700
@@ -177,6 +177,7 @@
 
 $(SRC)/cache.sml
 $(SRC)/toy_cache.sml
+$(SRC)/lru_cache.sml
 
 $(SRC)/sqlcache.sig
 $(SRC)/sqlcache.sml
--- a/src/sqlcache.sml	Wed May 06 23:11:30 2015 -0400
+++ b/src/sqlcache.sml	Sun Jun 28 12:46:51 2015 -0700
@@ -39,7 +39,7 @@
                      andalso not (m = "Basis" andalso SS.member (fs, f))
     end
 
-val cache = ref ToyCache.cache
+val cache = ref LruCache.cache
 fun setCache c = cache := c
 fun getCache () = !cache
 
@@ -52,8 +52,8 @@
        false, then expression is definitely not effectful if effs is fully
        populated. The intended pattern is to use this a number of times equal
        to the number of declarations in a file, Bellman-Ford style. *)
-    (* TODO: make incrementing of bound less janky, probably by using [MonoUtil]
-       instead of all this. *)
+    (* TODO: make incrementing of the number of bound variables cleaner,
+       probably by using [MonoUtil] instead of all this. *)
     let
         (* DEBUG: remove printing when done. *)
         fun tru msg = if doPrint then (print (msg ^ "\n"); true) else true
@@ -138,14 +138,14 @@
 
 (* Boolean formula normalization. *)
 
-datatype normalForm = Cnf | Dnf
+datatype junctionType = Conj | Disj
 
 datatype 'atom formula =
          Atom of 'atom
        | Negate of 'atom formula
-       | Combo of normalForm * 'atom formula list
+       | Combo of junctionType * 'atom formula list
 
-val flipNf = fn Cnf => Dnf | Dnf => Cnf
+val flipJt = fn Conj => Disj | Disj => Conj
 
 fun bind xs f = List.concat (map f xs)
 
@@ -158,7 +158,7 @@
 fun pushNegate (negate : 'atom -> 'atom) (negating : bool) =
  fn Atom x => Atom (if negating then negate x else x)
   | Negate f => pushNegate negate (not negating) f
-  | Combo (n, fs) => Combo (if negating then flipNf n else n, map (pushNegate negate negating) fs)
+  | Combo (n, fs) => Combo (if negating then flipJt n else n, map (pushNegate negate negating) fs)
 
 val rec flatten =
  fn Combo (n, fs) =>
@@ -170,17 +170,17 @@
                          (map flatten fs))
   | f => f
 
-fun normalize' (negate : 'atom -> 'atom) (norm : normalForm) =
+fun normalize' (negate : 'atom -> 'atom) (junc : junctionType) =
  fn Atom x => [[x]]
-  | Negate f => map (map negate) (normalize' negate (flipNf norm) f)
-  | Combo (n, fs) =>
+  | Negate f => map (map negate) (normalize' negate (flipJt junc) f)
+  | Combo (j, fs) =>
     let
-        val fss = bind fs (normalize' negate n)
+        val fss = bind fs (normalize' negate j)
     in
-        if n = norm then fss else cartesianProduct fss
+        if j = junc then fss else cartesianProduct fss
     end
 
-fun normalize negate norm = normalize' negate norm o flatten o pushNegate negate false
+fun normalize negate junc = normalize' negate junc o flatten o pushNegate negate false
 
 fun mapFormula mf =
  fn Atom x => Atom (mf x)
@@ -200,36 +200,29 @@
        | Prim of Prim.t
        | Field of string * string
 
-val equalAtomExp =
-    let
-        val isEqual = fn EQUAL => true | _ => false
-    in
-     fn (QueryArg n1, QueryArg n2) => n1 = n2
-      | (DmlRel n1, DmlRel n2) => n1 = n2
-      | (Prim p1, Prim p2) => isEqual (Prim.compare (p1, p2))
-      | (Field (t1, f1), Field (t2, f2)) => isEqual (String.compare (t1 ^ "." ^ f1, t2 ^ "." ^ f2))
-      | _ => false
-    end
-
 structure AtomExpKey : ORD_KEY = struct
 
-type ord_key = atomExp
+    type ord_key = atomExp
 
-val compare =
- fn (QueryArg n1, QueryArg n2) => Int.compare (n1, n2)
-  | (QueryArg _, _) => LESS
-  | (_, QueryArg _) => GREATER
-  | (DmlRel n1, DmlRel n2) => Int.compare (n1, n2)
-  | (DmlRel _, _) => LESS
-  | (_, DmlRel _) => GREATER
-  | (Prim p1, Prim p2) => Prim.compare (p1, p2)
-  | (Prim _, _) => LESS
-  | (_, Prim _) => GREATER
-  | (Field (t1, f1), Field (t2, f2)) => String.compare (t1 ^ "." ^ f1, t2 ^ "." ^ f2)
+    val compare =
+     fn (QueryArg n1, QueryArg n2) => Int.compare (n1, n2)
+      | (QueryArg _, _) => LESS
+      | (_, QueryArg _) => GREATER
+      | (DmlRel n1, DmlRel n2) => Int.compare (n1, n2)
+      | (DmlRel _, _) => LESS
+      | (_, DmlRel _) => GREATER
+      | (Prim p1, Prim p2) => Prim.compare (p1, p2)
+      | (Prim _, _) => LESS
+      | (_, Prim _) => GREATER
+      | (Field (t1, f1), Field (t2, f2)) =>
+        case String.compare (t1, t2) of
+            EQUAL => String.compare (f1, f2)
+          | ord => ord
 
 end
 
 structure UF = UnionFindFn(AtomExpKey)
+
 val conflictMaps : (Sql.cmp * Sql.sqexp * Sql.sqexp) formula
                    * (Sql.cmp * Sql.sqexp * Sql.sqexp) formula
                    -> atomExp IM.map list =
@@ -246,7 +239,9 @@
             o List.mapPartial toKnownEquality
         fun addToEqs (eqs, n, e) =
             case IM.find (eqs, n) of
-                (* Comparing to a constant seems better? *)
+                (* Comparing to a constant is probably better than comparing to
+                   a variable? Checking that an existing constant matches a new
+                   one is handled by [accumulateEqs]. *)
                 SOME (Prim _) => eqs
               | _ => IM.insert (eqs, n, e)
         val accumulateEqs =
@@ -263,6 +258,9 @@
           (* TODO: deal with equalities involving just [DmlRel]s and [Prim]s.
              This would involve guarding the invalidation with a check for the
              relevant comparisons. *)
+          (* DEBUG: remove these print statements. *)
+          (* | ((DmlRel r, Prim p), eqso) => (print ("sadness " ^ Int.toString r ^ " = " ^ Prim.toString p ^ "\n"); eqso) *)
+          (* | ((Prim p, DmlRel r), eqso) => (print ("sadness " ^ Int.toString r ^ " = " ^ Prim.toString p ^ "\n"); eqso) *)
           | (_, eqso) => eqso
         val eqsOfClass : atomExp list -> atomExp IM.map option =
             List.foldl accumulateEqs (SOME IM.empty)
@@ -275,7 +273,8 @@
                   | Sql.Field tf => SOME (Field tf)
                   | Sql.Inj (EPrim p, _) => SOME (Prim p)
                   | Sql.Inj (ERel n, _) => SOME (rel n)
-                  (* We can't deal with anything else. *)
+                  (* We can't deal with anything else, e.g., CURRENT_TIMESTAMP
+                     becomes Sql.Unmodeled, which becomes NONE here. *)
                   | _ => NONE
             in
                 (cmp, qa e1, qa e2)
@@ -302,17 +301,17 @@
             List.foldr (fn (SOME eqs, SOME acc) => SOME (IM.unionWith #1 (eqs, acc)) | _ => NONE)
                        (SOME IM.empty)
         fun dnf (fQuery, fDml) =
-            normalize negateCmp Dnf (Combo (Cnf, [markQuery fQuery, markDml fDml]))
+            normalize negateCmp Disj (Combo (Conj, [markQuery fQuery, markDml fDml]))
     in
         List.mapPartial (mergeEqs o map eqsOfClass o equivClasses) o dnf
     end
 
 val rec sqexpToFormula =
- fn Sql.SqTrue => Combo (Cnf, [])
-  | Sql.SqFalse => Combo (Dnf, [])
+ fn Sql.SqTrue => Combo (Conj, [])
+  | Sql.SqFalse => Combo (Disj, [])
   | Sql.SqNot e => Negate (sqexpToFormula e)
   | Sql.Binop (Sql.RCmp c, e1, e2) => Atom (c, e1, e2)
-  | Sql.Binop (Sql.RLop l, p1, p2) => Combo (case l of Sql.And => Cnf | Sql.Or => Dnf,
+  | Sql.Binop (Sql.RLop l, p1, p2) => Combo (case l of Sql.And => Conj | Sql.Or => Disj,
                                              [sqexpToFormula p1, sqexpToFormula p2])
   (* ASK: any other sqexps that can be props? *)
   | _ => raise Match
@@ -332,13 +331,13 @@
     end
 
 val rec queryToFormula =
- fn Sql.Query1 {Where = NONE, ...} => Combo (Cnf, [])
+ fn Sql.Query1 {Where = NONE, ...} => Combo (Conj, [])
   | Sql.Query1 {From = tablePairs, Where = SOME e, ...} =>
     renameTables tablePairs (sqexpToFormula e)
-  | Sql.Union (q1, q2) => Combo (Dnf, [queryToFormula q1, queryToFormula q2])
+  | Sql.Union (q1, q2) => Combo (Disj, [queryToFormula q1, queryToFormula q2])
 
 fun valsToFormula (table, vals) =
-    Combo (Cnf, map (fn (field, v) => Atom (Sql.Eq, Sql.Field (table, field), v)) vals)
+    Combo (Conj, map (fn (field, v) => Atom (Sql.Eq, Sql.Field (table, field), v)) vals)
 
 val rec dmlToFormula =
  fn Sql.Insert (table, vals) => valsToFormula (table, vals)
@@ -354,8 +353,8 @@
         val mark = mapFormula (fn (cmp, e1, e2) => (cmp, markField e1, markField e2))
     in
         renameTables [(table, "T")]
-                     (Combo (Dnf, [Combo (Cnf, [fVals, mark fWhere]),
-                                   Combo (Cnf, [mark fVals, fWhere])]))
+                     (Combo (Disj, [Combo (Conj, [fVals, mark fWhere]),
+                                   Combo (Conj, [mark fVals, fWhere])]))
     end
 
 val rec tablesQuery =
@@ -370,6 +369,13 @@
 
 (* Program instrumentation. *)
 
+val varName =
+    let
+        val varNumber = ref 0
+    in
+        fn s => (varNumber := !varNumber + 1; s ^ Int.toString (!varNumber))
+    end
+
 val {check, store, flush, ...} = getCache ()
 
 val dummyLoc = ErrorMsg.dummySpan
@@ -412,8 +418,8 @@
     in
         ECase (check,
                [((PNone stringTyp, loc),
-                 (ELet ("q", resultTyp, query, (ESeq (store, rel0), loc)), loc)),
-                ((PSome (stringTyp, (PVar ("hit", stringTyp), loc)), loc),
+                 (ELet (varName "q", resultTyp, query, (ESeq (store, rel0), loc)), loc)),
+                ((PSome (stringTyp, (PVar (varName "hit", stringTyp), loc)), loc),
                  (* Boolean is false because we're not unurlifying from a cookie. *)
                  (EUnurlify (rel0, resultTyp, false), loc))],
                {disc = stringTyp, result = resultTyp})
@@ -454,7 +460,7 @@
                 chunks
         fun wrapLets e' =
             (* Important that this is foldl (to oppose foldr above). *)
-            List.foldl (fn (v, e') => ELet ("sqlArg", stringTyp, v, (e', loc)))
+            List.foldl (fn (v, e') => ELet (varName "sqlArg", stringTyp, v, (e', loc)))
                        e'
                        newVariables
         val numArgs = length newVariables
@@ -482,6 +488,7 @@
                                                 exps = exps},
                                         dummyLoc)
                 val (EQuery {query = queryText, ...}, _) = queryExp
+                (* DEBUG: we can remove the following line at some point. *)
                 val () = Print.preface ("sqlcache> ", (MonoPrint.p_exp MonoEnv.empty queryText))
                 val args = List.tabulate (numArgs, fn n => (ERel n, dummyLoc))
                 fun bind x f = Option.mapPartial f x
@@ -530,9 +537,11 @@
         (* Tests if [ys] makes [xs] a redundant cache invalidation. [NONE] here
            represents unknown, which means a wider invalidation. *)
         val rec madeRedundantBy : atomExp option list * atomExp option list -> bool =
-         fn ([], []) => true
+         fn ([], []) => (print "hey!\n"; true)
           | (NONE :: xs, _ :: ys) => madeRedundantBy (xs, ys)
-          | (SOME x :: xs, SOME y :: ys) => equalAtomExp (x, y) andalso madeRedundantBy (xs, ys)
+          | (SOME x :: xs, SOME y :: ys) => (case AtomExpKey.compare (x, y) of
+                                                 EQUAL => madeRedundantBy (xs, ys)
+                                               | _ => false)
           | _ => false
         fun removeRedundant' (xss, yss) =
             case xss of