MDEV-16232: Use fewer mini-transactions10.9-MDEV-16232

SQL Layer support #3.
Add checks of applicability for UPDATEs and DELETEs.

Rename "operations batch" to "mini transactions" to disambiguate
the term "batch" which is already used.

Temporary disable mini-transactions for SELECTs.

1 files changed, 10 insertions, 1 deletions

diff --git a/sql/opt_range.h b/sql/opt_range.h
index f3ccd4d8311..22ddce91e96 100644
--- a/sql/opt_range.h
+++ b/sql/opt_range.h
@@ -1264,6 +1264,8 @@ public:
     This is used by an optimization in filesort.
   */
   virtual void add_used_key_part_to_set()=0;
+
+  virtual bool are_mini_transactions_applicable() const= 0;
 };
 
 
@@ -1361,6 +1363,8 @@ public:
   QUICK_SELECT_I *make_reverse(uint used_key_parts_arg);
 
   virtual void add_used_key_part_to_set();
+  bool are_mini_transactions_applicable() const override
+  { return !in_ror_merged_scan && !mrr_flags; }
 
 private:
   /* Default copy ctor used by QUICK_SELECT_DESC */
@@ -1398,7 +1402,6 @@ private:
 
 };
 
-
 class QUICK_RANGE_SELECT_GEOM: public QUICK_RANGE_SELECT
 {
 public:
@@ -1531,6 +1534,7 @@ public:
   READ_RECORD read_record;
 
   virtual void add_used_key_part_to_set();
+  bool are_mini_transactions_applicable() const override { return false; }
 };
 
 
@@ -1642,6 +1646,8 @@ public:
     return valid;
   }
 
+  bool are_mini_transactions_applicable() const override { return false; }
+
   /*
     Merged quick select that uses Clustered PK, if there is one. This quick
     select is not used for row retrieval, it is used for row retrieval.
@@ -1710,6 +1716,8 @@ public:
     return valid;
   }
 
+  bool are_mini_transactions_applicable() const override { return false; }
+
   QUEUE queue;    /* Priority queue for merge operation */
   MEM_ROOT alloc; /* Memory pool for this and merged quick selects data. */
 
@@ -1836,6 +1844,7 @@ public:
   bool is_agg_distinct() { return have_agg_distinct; }
   bool loose_scan_is_scanning() { return is_index_scan; }
   Explain_quick_select *get_explain(MEM_ROOT *alloc);
+  bool are_mini_transactions_applicable() const override { return true; }
 };