Added new status variables to make it easier to debug certain problems:

- Handler_read_retry
- Update_scan
- Delete_scan

7 files changed, 27 insertions, 3 deletions

diff --git a/sql/handler.cc b/sql/handler.cc
index 1816b9aa7eb..0edff665a33 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -2757,6 +2757,15 @@ int handler::ha_index_next_same(uchar *buf, const uchar *key, uint keylen)
   return result;
 }
 
+
+bool handler::ha_was_semi_consistent_read()
+{
+  bool result= was_semi_consistent_read();
+  if (result)
+    increment_statistics(&SSV::ha_read_retry_count);
+  return result;
+}
+
 /* Initialize handler for random reading, with error handling */
 
 int handler::ha_rnd_init_with_error(bool scan)
diff --git a/sql/handler.h b/sql/handler.h
index e2176f04933..772f2e68dab 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -3090,6 +3090,7 @@ public:
     If this method returns nonzero, it will also signal the storage
     engine that the next read will be a locking re-read of the row.
   */
+  bool ha_was_semi_consistent_read();
   virtual bool was_semi_consistent_read() { return 0; }
   /**
     Tell the engine whether it should avoid unnecessary lock waits.
diff --git a/sql/multi_range_read.cc b/sql/multi_range_read.cc
index 3f55ff3684d..e856400466d 100644
--- a/sql/multi_range_read.cc
+++ b/sql/multi_range_read.cc
@@ -267,7 +267,7 @@ int handler::multi_range_read_next(range_id_t *range_info)
     }
     else
     {
-      if (was_semi_consistent_read())
+      if (ha_was_semi_consistent_read())
       {
         /*
           The following assignment is redundant, but for extra safety and to
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index a1c13505304..826f2af3a85 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -7887,6 +7887,7 @@ SHOW_VAR status_vars[]= {
   {"Delayed_errors",           (char*) &delayed_insert_errors,  SHOW_LONG},
   {"Delayed_insert_threads",   (char*) &delayed_insert_threads, SHOW_LONG_NOFLUSH},
   {"Delayed_writes",           (char*) &delayed_insert_writes,  SHOW_LONG},
+  {"Delete_scan",	       (char*) offsetof(STATUS_VAR, delete_scan_count), SHOW_LONG_STATUS},
   {"Empty_queries",            (char*) offsetof(STATUS_VAR, empty_queries), SHOW_LONG_STATUS},
   {"Executed_events",          (char*) &executed_events, SHOW_LONG_NOFLUSH },
   {"Executed_triggers",        (char*) offsetof(STATUS_VAR, executed_triggers), SHOW_LONG_STATUS},
@@ -7915,6 +7916,7 @@ SHOW_VAR status_vars[]= {
   {"Handler_read_last",        (char*) offsetof(STATUS_VAR, ha_read_last_count), SHOW_LONG_STATUS},
   {"Handler_read_next",        (char*) offsetof(STATUS_VAR, ha_read_next_count), SHOW_LONG_STATUS},
   {"Handler_read_prev",        (char*) offsetof(STATUS_VAR, ha_read_prev_count), SHOW_LONG_STATUS},
+  {"Handler_read_retry",       (char*) offsetof(STATUS_VAR, ha_read_retry_count), SHOW_LONG_STATUS},
   {"Handler_read_rnd",         (char*) offsetof(STATUS_VAR, ha_read_rnd_count), SHOW_LONG_STATUS},
   {"Handler_read_rnd_deleted", (char*) offsetof(STATUS_VAR, ha_read_rnd_deleted_count), SHOW_LONG_STATUS},
   {"Handler_read_rnd_next",    (char*) offsetof(STATUS_VAR, ha_read_rnd_next_count), SHOW_LONG_STATUS},
@@ -8031,6 +8033,7 @@ SHOW_VAR status_vars[]= {
   {"Threads_connected",        (char*) &connection_count,       SHOW_INT},
   {"Threads_created",	       (char*) &thread_created,		SHOW_LONG_NOFLUSH},
   {"Threads_running",          (char*) &thread_running,         SHOW_INT},
+  {"Update_scan",	       (char*) offsetof(STATUS_VAR, update_scan_count), SHOW_LONG_STATUS},
   {"Uptime",                   (char*) &show_starttime,         SHOW_SIMPLE_FUNC},
 #ifdef ENABLED_PROFILING
   {"Uptime_since_flush_status",(char*) &show_flushstatustime,   SHOW_SIMPLE_FUNC},
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 8820205e8a2..f56ffbc1cc3 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -666,9 +666,11 @@ typedef struct system_status_var
   ulong ha_read_key_count;
   ulong ha_read_next_count;
   ulong ha_read_prev_count;
+  ulong ha_read_retry_count;
   ulong ha_read_rnd_count;
   ulong ha_read_rnd_next_count;
   ulong ha_read_rnd_deleted_count;
+
   /*
     This number doesn't include calls to the default implementation and
     calls made by range access. The intent is to count only calls made by
@@ -702,6 +704,8 @@ typedef struct system_status_var
   ulong select_range_count_;
   ulong select_range_check_count_;
   ulong select_scan_count_;
+  ulong update_scan_count;
+  ulong delete_scan_count;
   ulong executed_triggers;
   ulong long_query_count;
   ulong filesort_merge_passes_;
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index 64f5c85ef22..ce7da3cd33a 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -466,6 +466,9 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   DBUG_EXECUTE_IF("show_explain_probe_delete_exec_start", 
                   dbug_serve_apcs(thd, 1););
 
+  if (!(select && select->quick))
+    status_var_increment(thd->status_var.delete_scan_count);
+
   if (query_plan.using_filesort)
   {
     ha_rows examined_rows;
diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index b2af075e2f4..55dc26ef043 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -528,6 +528,9 @@ int mysql_update(THD *thd,
   DBUG_EXECUTE_IF("show_explain_probe_update_exec_start", 
                   dbug_serve_apcs(thd, 1););
   
+  if (!(select && select->quick))
+    status_var_increment(thd->status_var.update_scan_count);
+
   if (query_plan.using_filesort || query_plan.using_io_buffer)
   {
     /*
@@ -594,6 +597,7 @@ int mysql_update(THD *thd,
         close_cached_file(&tempfile);
         goto err;
       }
+
       table->file->try_semi_consistent_read(1);
 
       /*
@@ -631,7 +635,7 @@ int mysql_update(THD *thd,
         thd->inc_examined_row_count(1);
 	if (!select || (error= select->skip_record(thd)) > 0)
 	{
-          if (table->file->was_semi_consistent_read())
+          if (table->file->ha_was_semi_consistent_read())
 	    continue;  /* repeat the read of the same row if it still exists */
 
 	  table->file->position(table->record[0]);
@@ -746,7 +750,7 @@ int mysql_update(THD *thd,
     thd->inc_examined_row_count(1);
     if (!select || select->skip_record(thd) > 0)
     {
-      if (table->file->was_semi_consistent_read())
+      if (table->file->ha_was_semi_consistent_read())
         continue;  /* repeat the read of the same row if it still exists */
 
       store_record(table,record[1]);