bzr commit into mysql-5.1-innodb branch (vasil.dimov:3618) Bug#56340

[vasil.dimov]

#At file:///usr/local/devel/bzrroot/server/mysql-5.1-innodb/ based on revid:vasil.dimov@stripped

 3618 Vasil Dimov	2010-09-30
      Fix Bug#56340 innodb updates index stats too frequently after non-index updates
      
      This is a simple optimization issue. All stats are related to only indexed
      columns, index size or number of rows in the whole table. UPDATEs that touch
      only non-indexed columns cannot affect stats and we can avoid calling the
      function row_update_statistics_if_needed() which may result in unnecessary I/O.
      
      Approved by:	Marko (rb://466)

    modified:
      storage/innobase/row/row0mysql.c
      storage/innodb_plugin/row/row0mysql.c
=== modified file 'storage/innobase/row/row0mysql.c'
--- a/storage/innobase/row/row0mysql.c	revid:vasil.dimov@stripped
+++ b/storage/innobase/row/row0mysql.c	revid:vasil.dimov@stripped
@@ -1447,7 +1447,12 @@ run_again:
 		srv_n_rows_updated++;
 	}
 
-	row_update_statistics_if_needed(prebuilt->table);
+	/* We update table statistics only if it is a DELETE or UPDATE
+	that changes indexed columns, UPDATEs that change only non-indexed
+	columns would not affect statistics. */
+	if (node->is_delete || !(node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) {
+		row_update_statistics_if_needed(prebuilt->table);
+	}
 
 	trx->op_info = "";
 

=== modified file 'storage/innodb_plugin/row/row0mysql.c'
--- a/storage/innodb_plugin/row/row0mysql.c	revid:vasil.dimov@stripped
+++ b/storage/innodb_plugin/row/row0mysql.c	revid:vasil.dimov@stripped
@@ -1422,7 +1422,12 @@ run_again:
 		srv_n_rows_updated++;
 	}
 
-	row_update_statistics_if_needed(prebuilt->table);
+	/* We update table statistics only if it is a DELETE or UPDATE
+	that changes indexed columns, UPDATEs that change only non-indexed
+	columns would not affect statistics. */
+	if (node->is_delete || !(node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)) {
+		row_update_statistics_if_needed(prebuilt->table);
+	}
 
 	trx->op_info = "";
 


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