Fix Bug#57252 disabling innobase_stats_on_metadata disables ANALYZE

In order to fix this bug we need to distinguish whether ha_innobase::info()
has been called from ::analyze() or not. Rename ::info() to ::info_low()
and add a boolean parameter that tells whether the call is from ::analyze()
or not. Create a new simple ::info() that just calls
::info_low(false => not called from analyze). From ::analyze() instead of
::info() call ::info_low(true => called from analyze).

Approved by:	Jimmy (rb://487)

mysql-test/suite/innodb/r/innodb_bug57252.result

+cardinality
+10
+Table	Op	Msg_type	Msg_text
+test.bug57252	analyze	status	OK
+cardinality
+10

mysql-test/suite/innodb/t/innodb_bug57252.test

+#
+# Bug#57252 disabling innobase_stats_on_metadata disables ANALYZE
+# http://bugs.mysql.com/57252
+#
+
+-- source include/have_innodb.inc
+
+-- disable_query_log
+-- disable_result_log
+
+SET @innodb_stats_on_metadata_orig = @@innodb_stats_on_metadata;
+
+CREATE TABLE bug57252 (a INT, KEY akey (a)) ENGINE=INNODB;
+
+BEGIN;
+let $i = 10;
+while ($i) {
+	eval INSERT INTO bug57252 VALUES ($i);
+	dec $i;
+}
+COMMIT;
+
+-- enable_result_log
+
+SET GLOBAL innodb_stats_on_metadata=0;
+
+# this calls ::info() without HA_STATUS_CONST and so
+# index->stat_n_diff_key_vals[] is not copied to the mysql-visible
+# rec_per_key
+SELECT cardinality FROM information_schema.statistics
+WHERE table_name='bug57252' AND index_name='akey';
+
+# this calls ::info() with HA_STATUS_CONST and so
+# index->stat_n_diff_key_vals[] is copied to the mysql-visible
+# rec_per_key at the end; when the bug is present dict_update_statistics()
+# is not called beforehand and so index->stat_n_diff_key_vals[] contains
+# an outdated data and thus we get an outdated data in the result when the
+# bug is present
+ANALYZE TABLE bug57252;
+
+SELECT cardinality FROM information_schema.statistics
+WHERE table_name='bug57252' AND index_name='akey';
+
+DROP TABLE bug57252;
+
+SET GLOBAL innodb_stats_on_metadata = @innodb_stats_on_metadata_orig;

storage/innobase/handler/ha_innodb.cc

@@ -6367,9 +6367,12 @@ Returns statistics information of the table to the MySQL interpreter,
 in various fields of the handle object. */
 
 int
-ha_innobase::info(
-/*==============*/
-	uint flag)	/* in: what information MySQL requests */
+ha_innobase::info_low(
+/*==================*/
+	uint	flag,			/* in: what information MySQL
+					requests */
+	bool	called_from_analyze)	/* in: TRUE if called from
+					::analyze() */
 {
 	dict_table_t*	ib_table;
 	dict_index_t*	index;
@@ -6400,7 +6403,7 @@ ha_innobase::info(
 	ib_table = prebuilt->table;
 
 	if (flag & HA_STATUS_TIME) {
-		if (innobase_stats_on_metadata) {
+		if (called_from_analyze || innobase_stats_on_metadata) {
 			/* In sql_show we call with this flag: update
 			then statistics so that they are up-to-date */
 
@@ -6616,6 +6619,18 @@ func_exit:
   	DBUG_RETURN(0);
 }
 
+/*************************************************************************
+Returns statistics information of the table to the MySQL interpreter,
+in various fields of the handle object. */
+
+int
+ha_innobase::info(
+/*==============*/
+	uint flag)	/* in: what information MySQL requests */
+{
+	return(info_low(flag, false /* not called from analyze */));
+}
+
 /**************************************************************************
 Updates index cardinalities of the table, based on 8 random dives into
 each index tree. This does NOT calculate exact statistics on the table. */
@@ -6632,7 +6647,8 @@ ha_innobase::analyze(
 	pthread_mutex_lock(&analyze_mutex);
 
 	/* Simply call ::info() with all the flags */
-	info(HA_STATUS_TIME | HA_STATUS_CONST | HA_STATUS_VARIABLE);
+	info_low(HA_STATUS_TIME | HA_STATUS_CONST | HA_STATUS_VARIABLE,
+		 true /* called from analyze */);
 
 	pthread_mutex_unlock(&analyze_mutex);
 

storage/innobase/handler/ha_innodb.h

@@ -80,6 +80,7 @@ class ha_innobase: public handler
 	ulong innobase_update_autoinc(ulonglong	auto_inc);
 	void innobase_initialize_autoinc();
 	dict_index_t* innobase_get_index(uint keynr);
+	int info_low(uint flag, bool called_from_analyze);
 
 	/* Init values for the class: */
  public: