merge with 4.0

include/my_tree.h

@@ -22,7 +22,9 @@ extern "C" {
 
 #include "my_base.h"		/* get 'enum ha_rkey_function' */
 
-#define MAX_TREE_HEIGHT	40	/* = max 1048576 leafs in tree */
+/* Worst case tree is half full. This gives use 2^(MAX_TREE_HIGHT/2) leafs */
+#define MAX_TREE_HIGHT	64
+
 #define ELEMENT_KEY(tree,element)\
 (tree->offset_to_key ? (void*)((byte*) element+tree->offset_to_key) :\
 			*((void**) (element+1)))

innobase/btr/btr0cur.c

@@ -65,6 +65,16 @@ this many index pages */
 /*--------------------------------------*/
 #define BTR_BLOB_HDR_SIZE		8
 
+/***********************************************************************
+Marks all extern fields in a record as owned by the record. This function
+should be called if the delete mark of a record is removed: a not delete
+marked record always owns all its extern fields. */
+static
+void
+btr_cur_unmark_extern_fields(
+/*=========================*/
+	rec_t*	rec,	/* in: record in a clustered index */
+	mtr_t*	mtr);	/* in: mtr */
 /***********************************************************************
 Adds path information to the cursor for the current page, for which
 the binary search has been performed. */
@@ -2933,7 +2943,7 @@ btr_cur_mark_dtuple_inherited_extern(
 Marks all extern fields in a record as owned by the record. This function
 should be called if the delete mark of a record is removed: a not delete
 marked record always owns all its extern fields. */
-
+static
 void
 btr_cur_unmark_extern_fields(
 /*=========================*/

innobase/btr/btr0sea.c

@@ -22,7 +22,9 @@ Created 2/17/1996 Heikki Tuuri
 ulint	btr_search_this_is_zero = 0;	/* A dummy variable to fool the
 					compiler */
 
+#ifdef UNIV_SEARCH_PERF_STAT
 ulint	btr_search_n_succ	= 0;
+#endif /* UNIV_SEARCH_PERF_STAT */
 ulint	btr_search_n_hash_fail	= 0;
 
 byte	btr_sea_pad1[64];	/* padding to prevent other memory update

innobase/cry/makefilewin

-include ..\include\makefile.i
-
-doall: cr.exe dcr.exe wro.exe
-
-cr.exe: cry0cry.c
-	$(CCOM) $(CFLW) -o cr.exe -I.. cry0cry.c ..\ut.lib ..\os.lib
-
-dcr.exe: cry0dcr.c
-	$(CCOM) $(CFLW) -o dcr.exe -I.. cry0dcr.c ..\ut.lib ..\os.lib
-
-wro.exe: cry0wro.c
-	$(CCOM) $(CFLW) -o wro.exe -I.. cry0wro.c ..\ut.lib ..\os.lib

innobase/include/btr0cur.h

@@ -435,16 +435,6 @@ btr_cur_mark_dtuple_inherited_extern(
 	ulint		n_ext_vec,	/* in: number of elements in ext_vec */
 	upd_t*		update);	/* in: update vector */
 /***********************************************************************
-Marks all extern fields in a record as owned by the record. This function
-should be called if the delete mark of a record is removed: a not delete
-marked record always owns all its extern fields. */
-
-void
-btr_cur_unmark_extern_fields(
-/*=========================*/
-	rec_t*	rec,	/* in: record in a clustered index */
-	mtr_t*	mtr);	/* in: mtr */
-/***********************************************************************
 Marks all extern fields in a dtuple as owned by the record. */
 
 void

innobase/include/btr0sea.h

@@ -214,7 +214,9 @@ extern rw_lock_t*	btr_search_latch_temp;
 
 #define btr_search_latch	(*btr_search_latch_temp)
 
+#ifdef UNIV_SEARCH_PERF_STAT
 extern ulint	btr_search_n_succ;
+#endif /* UNIV_SEARCH_PERF_STAT */
 extern ulint	btr_search_n_hash_fail;
 
 /* After change in n_fields or n_bytes in info, this many rounds are waited

innobase/include/log0log.h

@@ -18,7 +18,9 @@ typedef struct log_struct	log_t;
 typedef struct log_group_struct	log_group_t;
 
 extern	ibool	log_do_write;
+#ifdef UNIV_LOG_DEBUG
 extern 	ibool	log_debug_writes;
+#endif /* UNIV_LOG_DEBUG */
 
 /* Wait modes for log_write_up_to */
 #define LOG_NO_WAIT		91
@@ -719,11 +721,13 @@ struct log_struct{
 	ulint		max_buf_free;	/* recommended maximum value of
 					buf_free, after which the buffer is
 					flushed */
+#ifdef UNIV_LOG_DEBUG
 	ulint		old_buf_free;	/* value of buf free when log was
 					last time opened; only in the debug
 					version */
 	dulint		old_lsn;	/* value of lsn when log was last time
 					opened; only in the debug version */
+#endif /* UNIV_LOG_DEBUG */
 	ibool		check_flush_or_checkpoint;
 					/* this is set to TRUE when there may
 					be need to flush the log buffer, or

innobase/include/log0log.ic

@@ -10,6 +10,7 @@ Created 12/9/1995 Heikki Tuuri
 #include "mach0data.h"
 #include "mtr0mtr.h"
 
+#ifdef UNIV_LOG_DEBUG
 /**********************************************************
 Checks by parsing that the catenated log segment for a single mtr is
 consistent. */
@@ -21,6 +22,7 @@ log_check_log_recs(
 				in the log_sys->buf log buffer */
 	ulint	len,		/* in: segment length in bytes */
 	dulint	buf_start_lsn);	/* in: buffer start lsn */
+#endif /* UNIV_LOG_DEBUG */
 
 /****************************************************************
 Gets a log block flush bit. */

innobase/include/page0cur.h

@@ -32,8 +32,11 @@ Created 10/4/1994 Heikki Tuuri
 				 which extend it */
 #define	PAGE_CUR_DBG	6
 
-
+#ifdef PAGE_CUR_ADAPT
+# ifdef UNIV_SEARCH_PERF_STAT
 extern ulint	page_cur_short_succ;
+# endif /* UNIV_SEARCH_PERF_STAT */
+#endif /* PAGE_CUR_ADAPT */
 
 /*************************************************************
 Gets pointer to the page frame where the cursor is positioned. */

innobase/include/que0que.h

@@ -307,22 +307,6 @@ que_thr_peek_stop(
 				mutex reserved is necessary before deciding
 				the actual stopping */
 	que_thr_t*	thr);	/* in: query thread */
-/***************************************************************************
-Returns TRUE if the query graph is for a SELECT statement. */
-UNIV_INLINE
-ibool
-que_graph_is_select(
-/*================*/
-					/* out: TRUE if a select */
-	que_t*		graph);		/* in: graph */
-/**************************************************************************
-Prints info of an SQL query graph node. */
-
-void
-que_node_print_info(
-/*================*/
-	que_node_t*	node);	/* in: query graph node */
-
 
 /* Query graph query thread node: the fields are protected by the kernel
 mutex with the exceptions named below */

innobase/include/que0que.ic

@@ -238,21 +238,3 @@ que_thr_peek_stop(
 
 	return(FALSE);
 }
-
-/***************************************************************************
-Returns TRUE if the query graph is for a SELECT statement. */
-UNIV_INLINE
-ibool
-que_graph_is_select(
-/*================*/
-					/* out: TRUE if a select */
-	que_t*		graph)		/* in: graph */
-{
-	if (graph->fork_type == QUE_FORK_SELECT_SCROLL
-			|| graph->fork_type == QUE_FORK_SELECT_NON_SCROLL) {
-
-	    	return(TRUE);
-	}
-
-	return(FALSE);
-}

innobase/log/log0log.c

@@ -32,7 +32,9 @@ ulint	log_fsp_current_free_limit		= 0;
 log_t*	log_sys	= NULL;
 
 ibool	log_do_write = TRUE;
+#ifdef UNIV_LOG_DEBUG
 ibool	log_debug_writes = FALSE;
+#endif /* UNIV_LOG_DEBUG */
 
 /* These control how often we print warnings if the last checkpoint is too
 old */
@@ -86,9 +88,8 @@ the previous */
 Completes a checkpoint write i/o to a log file. */
 static
 void
-log_io_complete_checkpoint(
-/*=======================*/
-	log_group_t*	group);	/* in: log group */
+log_io_complete_checkpoint(void);
+/*============================*/
 /**********************************************************
 Completes an archiving i/o. */
 static
@@ -928,11 +929,12 @@ log_group_check_flush_completion(
 #endif /* UNIV_SYNC_DEBUG */
 
 	if (!log_sys->one_flushed && group->n_pending_writes == 0) {
-
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			printf("Log flushed first to group %lu\n",
 			       (ulong) group->id);
 		}
+#endif /* UNIV_LOG_DEBUG */
 	
 		log_sys->written_to_some_lsn = log_sys->write_lsn;
 		log_sys->one_flushed = TRUE;
@@ -940,10 +942,12 @@ log_group_check_flush_completion(
 		return(LOG_UNLOCK_NONE_FLUSHED_LOCK);
 	}
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes && (group->n_pending_writes == 0)) {
 
 		printf("Log flushed to group %lu\n", (ulong) group->id);
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	return(0);
 }
@@ -1019,7 +1023,15 @@ log_io_complete(
 		        fil_flush(group->space_id);
 		}
 
-		log_io_complete_checkpoint(group);
+#ifdef UNIV_LOG_DEBUG
+		if (log_debug_writes) {
+			fprintf(stderr,
+				"Checkpoint info written to group %lu\n",
+				group->id);
+		}
+#endif /* UNIV_LOG_DEBUG */
+
+		log_io_complete_checkpoint();
 
 		return;
 	}
@@ -1084,11 +1096,13 @@ log_group_file_header_flush(
 
 	dest_offset = nth_file * group->file_size;
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		printf(
 		"Writing log file header to group %lu file %lu\n",
 		(ulong) group->id, (ulong) nth_file);
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	if (log_do_write) {
 		log_sys->n_log_ios++;	
@@ -1173,6 +1187,7 @@ loop:
 		write_len = len;
 	}
 	
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 
 		printf(
@@ -1197,6 +1212,7 @@ loop:
 					+ i * OS_FILE_LOG_BLOCK_SIZE));
 		}
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	/* Calculate the checksums for each log block and write them to
 	the trailer fields of the log blocks */
@@ -1324,6 +1340,7 @@ loop:
 		return;
 	}
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		printf("Writing log from %lu %lu up to lsn %lu %lu\n",
 			(ulong) ut_dulint_get_high(log_sys->written_to_all_lsn),
@@ -1331,6 +1348,7 @@ loop:
 			(ulong) ut_dulint_get_high(log_sys->lsn),
 			(ulong)	ut_dulint_get_low(log_sys->lsn));
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	log_sys->n_pending_writes++;
 
@@ -1556,9 +1574,8 @@ log_complete_checkpoint(void)
 Completes an asynchronous checkpoint info write i/o to a log file. */
 static
 void
-log_io_complete_checkpoint(
-/*=======================*/
-	log_group_t*	group)	/* in: log group */
+log_io_complete_checkpoint(void)
+/*============================*/
 {
 	mutex_enter(&(log_sys->mutex));
 
@@ -1566,11 +1583,6 @@ log_io_complete_checkpoint(
 	
 	log_sys->n_pending_checkpoint_writes--;
 
-	if (log_debug_writes) {
-		printf("Checkpoint info written to group %lu\n",
-		       (ulong) group->id);
-	}
-
 	if (log_sys->n_pending_checkpoint_writes == 0) {
 		log_complete_checkpoint();
 	}	
@@ -1895,12 +1907,14 @@ log_checkpoint(
 
 	log_sys->next_checkpoint_lsn = oldest_lsn;
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		printf("Making checkpoint no %lu at lsn %lu %lu\n",
 			(ulong) ut_dulint_get_low(log_sys->next_checkpoint_no),
 			(ulong) ut_dulint_get_high(oldest_lsn),
 			(ulong) ut_dulint_get_low(oldest_lsn));
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	log_groups_write_checkpoint_info();
 
@@ -2287,9 +2301,11 @@ loop:
 		  exit(1);
 		}
 
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			printf("Created archive file %s\n", name);
 		}
+#endif /* UNIV_LOG_DEBUG */
 
 		ret = os_file_close(file_handle);
 	
@@ -2316,6 +2332,7 @@ loop:
 		len = group->file_size - (next_offset % group->file_size);
 	}
 	
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		printf(
 		"Archiving starting at lsn %lu %lu, len %lu to group %lu\n",
@@ -2323,6 +2340,7 @@ loop:
 					(ulong) ut_dulint_get_low(start_lsn),
 					(ulong) len, (ulong) group->id);
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	log_sys->n_pending_archive_ios++;
 
@@ -2417,10 +2435,12 @@ log_archive_write_complete_groups(void)
 		trunc_files = n_files - 1;
 	}
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes && trunc_files) {
 		printf("Complete file(s) archived to group %lu\n",
 							  (ulong) group->id);
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	/* Calculate the archive file space start lsn */
 	start_lsn = ut_dulint_subtract(log_sys->next_archived_lsn,
@@ -2443,9 +2463,11 @@ log_archive_write_complete_groups(void)
 	fil_space_truncate_start(group->archive_space_id,
 					trunc_files * group->file_size);
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		printf("Archiving writes completed\n");
 	}
+#endif /* UNIV_LOG_DEBUG */
 }
 
 /**********************************************************
@@ -2464,9 +2486,11 @@ log_archive_check_completion_low(void)
 	if (log_sys->n_pending_archive_ios == 0
 			&& log_sys->archiving_phase == LOG_ARCHIVE_READ) {
 
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			printf("Archiving read completed\n");
 		}
+#endif /* UNIV_LOG_DEBUG */
 
 	    	/* Archive buffer has now been read in: start archive writes */
 
@@ -2729,12 +2753,14 @@ log_archive_close_groups(
 			group->archived_file_no += 2;
 		}
 
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			printf(
 			"Incrementing arch file no to %lu in log group %lu\n",
 				(ulong) group->archived_file_no + 2,
 			        (ulong) group->id);
 		}
+#endif /* UNIV_LOG_DEBUG */
 	}
 }
 
@@ -3204,6 +3230,7 @@ loop:
 	ut_a(0 == ut_dulint_cmp(lsn, log_sys->lsn));
 }
 
+#ifdef UNIV_LOG_DEBUG
 /**********************************************************
 Checks by parsing that the catenated log segment for a single mtr is
 consistent. */
@@ -3256,6 +3283,7 @@ log_check_log_recs(
 			
 	return(TRUE);
 }
+#endif /* UNIV_LOG_DEBUG */
 
 /**********************************************************
 Peeks the current lsn. */

innobase/log/log0recv.c

@@ -487,6 +487,7 @@ recv_find_max_checkpoint(
 			log_group_read_checkpoint_info(group, field);
 
 			if (!recv_check_cp_is_consistent(buf)) {
+#ifdef UNIV_LOG_DEBUG
 				if (log_debug_writes) {
 					fprintf(stderr, 
 	    "InnoDB: Checkpoint in group %lu at %lu invalid, %lu\n",
@@ -496,6 +497,7 @@ recv_find_max_checkpoint(
 					      + LOG_CHECKPOINT_CHECKSUM_1));
 
 				}
+#endif /* UNIV_LOG_DEBUG */
 
 				goto not_consistent;
 			}
@@ -509,12 +511,14 @@ recv_find_max_checkpoint(
 			checkpoint_no =
 				mach_read_from_8(buf + LOG_CHECKPOINT_NO);
 
+#ifdef UNIV_LOG_DEBUG
 			if (log_debug_writes) {
 				fprintf(stderr, 
 			"InnoDB: Checkpoint number %lu found in group %lu\n",
 				(ulong) ut_dulint_get_low(checkpoint_no),
 				(ulong) group->id);
 			}
+#endif /* UNIV_LOG_DEBUG */
 				
 			if (ut_dulint_cmp(checkpoint_no, max_no) >= 0) {
 				*max_group = group;
@@ -1147,6 +1151,7 @@ recv_recover_page(
 				start_lsn = recv->start_lsn;
 			}
 
+#ifdef UNIV_LOG_DEBUG
 			if (log_debug_writes) {
 				fprintf(stderr, 
      "InnoDB: Applying log rec type %lu len %lu to space %lu page no %lu\n",
@@ -1154,7 +1159,8 @@ recv_recover_page(
 					(ulong) recv_addr->space,
 					(ulong) recv_addr->page_no);
 			}
-					
+#endif /* UNIV_LOG_DEBUG */
+
 			recv_parse_or_apply_log_rec_body(recv->type, buf,
 						buf + recv->len, page, &mtr);
 			mach_write_to_8(page + UNIV_PAGE_SIZE
@@ -1984,12 +1990,14 @@ loop:
 		recv_sys->recovered_offset += len;
 		recv_sys->recovered_lsn = new_recovered_lsn;
 
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			fprintf(stderr, 
 "InnoDB: Parsed a single log rec type %lu len %lu space %lu page no %lu\n",
 				(ulong) type, (ulong) len, (ulong) space,
 				(ulong) page_no);
 		}
+#endif /* UNIV_LOG_DEBUG */
 
 		if (type == MLOG_DUMMY_RECORD) {
 			/* Do nothing */
@@ -2071,13 +2079,15 @@ loop:
 */
 			}
 			
+#ifdef UNIV_LOG_DEBUG
 			if (log_debug_writes) {
 				fprintf(stderr, 
 "InnoDB: Parsed a multi log rec type %lu len %lu space %lu page no %lu\n",
 				(ulong) type, (ulong) len, (ulong) space,
 				(ulong) page_no);
 			}
-		
+#endif /* UNIV_LOG_DEBUG */
+
 			total_len += len;
 			n_recs++;
 
@@ -2482,6 +2492,7 @@ recv_group_scan_log_recs(
 		start_lsn = end_lsn;
 	}
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		fprintf(stderr,
 	"InnoDB: Scanned group %lu up to log sequence number %lu %lu\n",
@@ -2489,6 +2500,7 @@ recv_group_scan_log_recs(
 				(ulong) ut_dulint_get_high(*group_scanned_lsn),
 				(ulong) ut_dulint_get_low(*group_scanned_lsn));
 	}
+#endif /* UNIV_LOG_DEBUG */
 }
 
 /************************************************************
@@ -2869,10 +2881,12 @@ recv_recovery_from_checkpoint_finish(void)
 		recv_apply_hashed_log_recs(TRUE);
 	}
 
+#ifdef UNIV_LOG_DEBUG
 	if (log_debug_writes) {
 		fprintf(stderr,
 		"InnoDB: Log records applied to the database\n");
 	}
+#endif /* UNIV_LOG_DEBUG */
 
 	if (recv_needed_recovery) {
 		trx_sys_print_mysql_master_log_pos();
@@ -3184,6 +3198,7 @@ ask_again:
 			break;
 		}
 	
+#ifdef UNIV_LOG_DEBUG
 		if (log_debug_writes) {
 			fprintf(stderr, 
 "InnoDB: Archive read starting at lsn %lu %lu, len %lu from file %s\n",
@@ -3191,6 +3206,7 @@ ask_again:
 					(ulong) ut_dulint_get_low(start_lsn),
 					(ulong) len, name);
 		}
+#endif /* UNIV_LOG_DEBUG */
 
 		fil_io(OS_FILE_READ | OS_FILE_LOG, TRUE,
 			group->archive_space_id, read_offset / UNIV_PAGE_SIZE,

innobase/page/page0cur.c

@@ -16,11 +16,12 @@ Created 10/4/1994 Heikki Tuuri
 #include "log0recv.h"
 #include "rem0cmp.h"
 
-ulint	page_cur_short_succ	= 0;
-
-ulint	page_rnd	= 976722341;
+static ulint	page_rnd	= 976722341;
 
 #ifdef PAGE_CUR_ADAPT
+# ifdef UNIV_SEARCH_PERF_STAT
+ulint	page_cur_short_succ	= 0;
+# endif /* UNIV_SEARCH_PERF_STAT */
 
 /********************************************************************
 Tries a search shortcut based on the last insert. */

innobase/que/que0que.c

@@ -1036,9 +1036,10 @@ que_thr_stop_for_mysql_no_error(
 	trx->n_active_thrs--;
 }
 
+#ifdef UNIV_DEBUG
 /**************************************************************************
 Prints info of an SQL query graph node. */
-
+static
 void
 que_node_print_info(
 /*================*/
@@ -1095,6 +1096,7 @@ que_node_print_info(
 
 	fprintf(stderr, "Node type %lu: %s, address %p\n", (ulong) type, str, node);
 }
+#endif /* UNIV_DEBUG */
 
 /**************************************************************************
 Performs an execution step on a query thread. */

myisam/myisam_ftdump.c

@@ -267,7 +267,7 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
 
 static void usage()
 {
-  printf("Use: ft_dump <table_name> <index_no>\n");
+  printf("Use: myisam_ftdump <table_name> <index_num>\n");
   my_print_help(my_long_options);
   my_print_variables(my_long_options);
   exit(1);

mysql-test/r/func_if.result

@@ -59,6 +59,12 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 Warnings:
 Note	1003	select high_priority nullif((test.t1.u = 0),_latin1'test') AS `nullif(u=0, 'test')` from test.t1
 drop table t1;
+select NULLIF(NULL,NULL), NULLIF(NULL,1), NULLIF(NULL,1.0), NULLIF(NULL,"test");
+NULLIF(NULL,NULL)	NULLIF(NULL,1)	NULLIF(NULL,1.0)	NULLIF(NULL,"test")
+NULL	NULL	NULL	NULL
+select NULLIF(1,NULL), NULLIF(1.0, NULL), NULLIF("test", NULL);
+NULLIF(1,NULL)	NULLIF(1.0, NULL)	NULLIF("test", NULL)
+1	1.0	test
 create table t1 (num  double(12,2));
 insert into t1 values (144.54);
 select sum(if(num is null,0.00,num)) from t1;

mysql-test/t/func_if.test

@@ -29,6 +29,12 @@ select nullif(u=0, 'test') from t1;
 explain extended select nullif(u=0, 'test') from t1;
 drop table t1;
 
+#
+# Bug 2629
+#
+select NULLIF(NULL,NULL), NULLIF(NULL,1), NULLIF(NULL,1.0), NULLIF(NULL,"test");
+select NULLIF(1,NULL), NULLIF(1.0, NULL), NULLIF("test", NULL);
+
 #
 # Problem with IF()
 #

sql/item_cmpfunc.cc

@@ -977,7 +977,7 @@ double
 Item_func_nullif::val()
 {
   double value;
-  if (!cmp.compare() || null_value)
+  if (!cmp.compare())
   {
     null_value=1;
     return 0.0;
@@ -991,7 +991,7 @@ longlong
 Item_func_nullif::val_int()
 {
   longlong value;
-  if (!cmp.compare() || null_value)
+  if (!cmp.compare())
   {
     null_value=1;
     return 0;
@@ -1005,7 +1005,7 @@ String *
 Item_func_nullif::val_str(String *str)
 {
   String *res;
-  if (!cmp.compare() || null_value)
+  if (!cmp.compare())
   {
     null_value=1;
     return 0;