--- btr/btr0sea.c.orig	2005-09-03 01:38:01.000000000 +0300
+++ btr/btr0sea.c	2006-01-24 14:25:10.000000000 +0200
@@ -191,7 +191,7 @@
 void
 btr_search_info_update_hash(
 /*========================*/
-	btr_search_t*	info,	/* in: search info */
+	btr_search_t*	info,	/* in/out: search info */
 	btr_cur_t*	cursor)	/* in: cursor which was just positioned */
 {
 	dict_index_t*	index;
@@ -443,7 +443,7 @@
 void
 btr_search_info_update_slow(
 /*========================*/
-	btr_search_t*	info,	/* in: search info */
+	btr_search_t*	info,	/* in/out: search info */
 	btr_cur_t*	cursor)	/* in: cursor which was just positioned */
 {
 	buf_block_t*	block;
@@ -931,7 +931,7 @@
 	ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_SHARED));
 	ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_EX));
 #endif /* UNIV_SYNC_DEBUG */
-
+retry:
 	rw_lock_s_lock(&btr_search_latch);
 
 	block = buf_block_align(page);
@@ -1007,6 +1007,24 @@
 
 	rw_lock_x_lock(&btr_search_latch);
 
+	if (!block->is_hashed) {
+		/* Someone else has meanwhile dropped the hash index */
+
+		goto cleanup;
+	}
+
+	if (block->curr_n_fields != n_fields
+	    || block->curr_n_bytes != n_bytes) {
+
+		/* Someone else has meanwhile built a new hash index on the
+		page, with different parameters */
+
+		rw_lock_x_unlock(&btr_search_latch);
+
+		mem_free(folds);
+		goto retry;
+	}
+
 	for (i = 0; i < n_cached; i++) {
 
 		ha_remove_all_nodes_to_page(table, folds[i], page);
@@ -1014,6 +1032,7 @@
 
 	block->is_hashed = FALSE;
 
+cleanup:
 	rw_lock_x_unlock(&btr_search_latch);
 
 	mem_free(folds);