diff -Naru ../senna-1.1.3.orig/lib/index.c ./lib/index.c
--- ../senna-1.1.3.orig/lib/index.c	2008-05-21 18:26:19.000000000 +0900
+++ ./lib/index.c	2008-11-04 07:34:05.000000000 +0900
@@ -585,6 +585,12 @@
   return r;
 }
 
+void
+sen_index_set_abort_callback(sen_index *i, int (*cb)(void*), void *arg)
+{
+  sen_inv_set_abort_callback(i->inv, cb, arg);
+}
+
 /* sen_records_heap class */
 
 struct _sen_records_heap {
diff -Naru ../senna-1.1.3.orig/lib/inv.c ./lib/inv.c
--- ../senna-1.1.3.orig/lib/inv.c	2008-05-21 18:26:19.000000000 +0900
+++ ./lib/inv.c	2008-11-04 07:36:28.000000000 +0900
@@ -51,6 +51,8 @@
   sen_io *chunk;
   sen_sym *lexicon;
   struct sen_inv_header *header;
+  int (*check_abort)(void*);
+  void *check_abort_arg;
 };
 
 struct sen_inv_header {
@@ -1302,6 +1304,8 @@
   inv->chunk = chunk;
   inv->header = header;
   inv->lexicon = lexicon;
+  inv->check_abort = NULL;
+  inv->check_abort_arg = NULL;
   inv->header->total_chunk_size = 0;
   SEN_GET(path,inv);
   return inv;
@@ -1408,6 +1412,13 @@
   }
 }
 
+void
+sen_inv_set_abort_callback(sen_inv *inv, int (*cb)(void*), void *arg)
+{
+  inv->check_abort = cb;
+  inv->check_abort_arg = arg;
+}
+
 sen_rc
 sen_inv_update_one(sen_inv *inv, uint32_t key, sen_inv_updspec *u, sen_set *h, int hint)
 {
@@ -2249,12 +2260,16 @@
   uint32_t *offset2;
   sen_set_cursor *c;
   sen_id *tp, *tq;
+  int check_abort_cnt = 0;
   if ((h = sen_sym_prefix_search(lexicon, key))) {
     // sen_log("key=%s h->n=%d", key, h->n_entries);
     if ((ti->cursors = cursor_heap_open(h->n_entries + 256))) {
       if ((c = sen_set_cursor_open(h))) {
         while (sen_set_cursor_next(c, (void **) &tp, NULL)) {
           const char *key2 = _sen_sym_key(lexicon, *tp);
+	  if (inv->check_abort != NULL && (++check_abort_cnt & 0x3f) == 0
+	      && (*inv->check_abort)(inv->check_abort_arg))
+	    break;
           if (!key2) { break; }
           // sen_log("key2=%s", key2);
           if (sen_str_len(key2, lexicon->encoding, NULL) == 1) { // todo:
diff -Naru ../senna-1.1.3.orig/lib/inv.h ./lib/inv.h
--- ../senna-1.1.3.orig/lib/inv.h	2008-05-21 18:26:19.000000000 +0900
+++ ./lib/inv.h	2008-11-04 07:36:49.000000000 +0900
@@ -80,6 +80,8 @@
 void sen_inv_seg_expire(sen_inv *inv, int32_t threshold);
 void sen_inv_expire(void);
 
+void sen_inv_set_abort_callback(sen_inv *inv, int (*cb)(void*), void *arg);
+
 typedef struct {
   sen_id rid;
   uint32_t sid;
diff -Naru ../senna-1.1.3.orig/lib/inv08.c ./lib/inv08.c
--- ../senna-1.1.3.orig/lib/inv08.c	2008-05-21 18:26:19.000000000 +0900
+++ ./lib/inv08.c	2008-11-04 07:37:19.000000000 +0900
@@ -29,6 +29,8 @@
   sen_io *chunk;
   sen_sym *lexicon;
   struct sen_inv_header *header;
+  int (*check_abort)(void*);
+  void *check_abort_arg;
   uint32_t total_chunk_size;
   uint16_t ainfo[SEN_INV_MAX_SEGMENT];
   uint16_t binfo[SEN_INV_MAX_SEGMENT];
@@ -1066,6 +1068,8 @@
   inv->chunk = chunk;
   inv->header = header;
   inv->lexicon = lexicon;
+  inv->check_abort = NULL;
+  inv->check_abort_arg = NULL;
   inv->total_chunk_size = 0;
   load_all_segments(inv);
   return inv;
diff -Naru ../senna-1.1.3.orig/senna.h ./senna.h
--- ../senna-1.1.3.orig/senna.h	2008-06-12 14:18:12.000000000 +0900
+++ ./senna.h	2008-11-04 07:38:05.000000000 +0900
@@ -310,6 +310,7 @@
                      const char *newvalue, unsigned int newvalue_len);
 sen_records *sen_index_sel(sen_index *i,
                            const char *string, unsigned int string_len);
+void sen_index_set_abort_callback(sen_index *i, int (*cb)(void*), void *arg);
 int sen_records_next(sen_records *r, void *keybuf, int buf_size, int *score);
 sen_rc sen_records_rewind(sen_records *r);
 int sen_records_curr_score(sen_records *r);