prototype of sampling code

4 files changed, 53 insertions, 2 deletions

diff --git a/sql/handler.h b/sql/handler.h
index 8ad521e189a..305b2afdf6a 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -4030,6 +4030,10 @@ public:
   virtual int ft_read(uchar *buf) { return HA_ERR_WRONG_COMMAND; }
   virtual int rnd_next(uchar *buf)=0;
   virtual int rnd_pos(uchar * buf, uchar *pos)=0;
+
+  virtual int sample_next(uchar *buf) { return 0;}
+
+
   /**
     This function only works for handlers having
     HA_PRIMARY_KEY_REQUIRED_FOR_POSITION set.
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc
index 1f034f490c8..ce856bc5204 100644
--- a/sql/sql_statistics.cc
+++ b/sql/sql_statistics.cc
@@ -2634,6 +2634,11 @@ int collect_statistics_for_table(THD *thd, TABLE *table)
   table->collected_stats->cardinality_is_null= TRUE;
   table->collected_stats->cardinality= 0;
 
+  int b = file->sample_next(table->record[0]);
+
+  b += 1;
+
+
   if (thd->variables.sample_percentage == 0)
   {
     if (file->records() < MIN_THRESHOLD_FOR_SAMPLING)
@@ -2650,14 +2655,18 @@ int collect_statistics_for_table(THD *thd, TABLE *table)
 
   for (field_ptr= table->field; *field_ptr; field_ptr++)
   {
-    table_field= *field_ptr;   
+    table_field= *field_ptr;
     if (!table_field->collected_stats)
-      continue; 
+      continue;
     table_field->collected_stats->init(thd, table_field);
   }
 
   restore_record(table, s->default_values);
 
+
+
+
+
   /* Perform a full table scan to collect statistics on 'table's columns */
   if (!(rc= file->ha_rnd_init(TRUE)))
   {
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 17a92a242fd..9d9a4453588 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -9489,6 +9489,42 @@ ha_innobase::rnd_next(
 	DBUG_RETURN(error);
 }
 
+#include "../row/row0sel.cc"
+
+int
+ha_innobase::sample_next(
+/*=====================*/
+    uchar *buf)
+{
+        int rc= ha_rnd_init(TRUE);
+        rc = rc;
+        mtr_t		mtr;
+        btr_pcur_t*	pcur = m_prebuilt->pcur;
+        rec_t*          rec;
+
+
+        rec_offs	offsets_[REC_OFFS_NORMAL_SIZE];
+        rec_offs*	offsets				= offsets_;
+        rec_offs_init(offsets_);
+        mtr.start();
+        dict_index_t*	index = innobase_get_index(MAX_KEY);
+        bool res = btr_pcur_open_at_rnd_pos(index, BTR_SEARCH_LEAF, pcur, &mtr);
+
+        rec = btr_pcur_get_rec(pcur);
+
+        mem_heap_t*	heap	= NULL;
+        offsets = rec_get_offsets(rec, index, offsets, index->n_core_fields, ULINT_UNDEFINED, &heap);
+        res = row_sel_store_mysql_rec(
+            buf, m_prebuilt, rec, NULL, true,
+            index, offsets);
+
+        res = res;
+
+        mtr.commit();
+        ha_rnd_end();
+        return 0;
+}
+
 /**********************************************************************//**
 Fetches a row from the table based on a row reference.
 @return 0, HA_ERR_KEY_NOT_FOUND, or error code */
diff --git a/storage/innobase/handler/ha_innodb.h b/storage/innobase/handler/ha_innodb.h
index 08501859ec9..f82d61e66f6 100644
--- a/storage/innobase/handler/ha_innodb.h
+++ b/storage/innobase/handler/ha_innodb.h
@@ -155,6 +155,8 @@ public:
 
 	int rnd_next(uchar *buf) override;
 
+        int sample_next(uchar *buf) override;
+
 	int rnd_pos(uchar * buf, uchar *pos) override;
 
 	int ft_init() override;