MDEV-22535 TABLE::initialize_quick_structures() takes 0.5% in oltp_read_only

Fixed by:
- Make all quick_* variable allocated according to real number keys instead
  of MAX_KEY
- Store all the quick* items in separated allocated structure (OPT_RANGE)
- Ensure we don't access any quick* variable without first checking
  opt_range_keys.is_set().  Thanks to this, we don't need any
  pre-initialization of quick* variables anymore.

Some renames was done to use the new structure:
table->quick_keys                -> table->opt_range_keys
table->quick_rows[X]             -> table->opt_range[X].rows
table->quick_key_parts[X]        -> table->opt_range[X].key_parts
table->quick_costs[X]            -> table->opt_range[X].cost
table->quick_index_only_costs[X] -> table->opt_range[X].index_only_cost
table->quick_n_ranges[X]         -> table->opt_range[X].ranges
table->quick_condition_rows      -> table->opt_range_condition_rows

This patch should both decrease memory needed for TABLE objects
(3528 -> 984 + keyinfo) and increase performance, thanks to less
initializations per query, and more localized memory, thanks to the
opt_range structure.

sql/opt_range.cc

@@ -2599,10 +2599,10 @@ static int fill_used_fields_bitmap(PARAM *param)
     In the table struct the following information is updated:
       quick_keys           - Which keys can be used
       quick_rows           - How many rows the key matches
-      quick_condition_rows - E(# rows that will satisfy the table condition)
+      opt_range_condition_rows - E(# rows that will satisfy the table condition)
 
   IMPLEMENTATION
-    quick_condition_rows value is obtained as follows:
+    opt_range_condition_rows value is obtained as follows:
       
       It is a minimum of E(#output rows) for all considered table access
       methods (range and index_merge accesses over various indexes).
@@ -2626,7 +2626,7 @@ static int fill_used_fields_bitmap(PARAM *param)
     which is currently produced.
 
   TODO
-   * Change the value returned in quick_condition_rows from a pessimistic
+   * Change the value returned in opt_range_condition_rows from a pessimistic
      estimate to true E(#rows that satisfy table condition). 
      (we can re-use some of E(#rows) calcuation code from
      index_merge/intersection for this)
@@ -2957,7 +2957,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
         {
           best_trp= intersect_trp;
           best_read_time= best_trp->read_cost; 
-          set_if_smaller(param.table->quick_condition_rows, 
+          set_if_smaller(param.table->opt_range_condition_rows,
                          intersect_trp->records);
         }
       }
@@ -2977,7 +2977,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
         {
           new_conj_trp= get_best_disjunct_quick(&param, imerge, best_read_time);
           if (new_conj_trp)
-            set_if_smaller(param.table->quick_condition_rows, 
+            set_if_smaller(param.table->opt_range_condition_rows,
                            new_conj_trp->records);
           if (new_conj_trp &&
               (!best_conj_trp || 
@@ -3004,7 +3004,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
         restore_nonrange_trees(&param, tree, backup_keys);
       if ((group_trp= get_best_group_min_max(&param, tree, read_time)))
       {
-        param.table->quick_condition_rows= MY_MIN(group_trp->records,
+        param.table->opt_range_condition_rows= MY_MIN(group_trp->records,
                                                   head->stat_records());
         Json_writer_object grp_summary(thd, "best_group_range_summary");
 
@@ -3340,8 +3340,8 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item **cond)
 
   for (keynr= 0;  keynr < table->s->keys; keynr++)
   {
-    if (table->quick_keys.is_set(keynr))
-      set_if_bigger(max_quick_key_parts, table->quick_key_parts[keynr]);
+    if (table->opt_range_keys.is_set(keynr))
+      set_if_bigger(max_quick_key_parts, table->opt_range[keynr].key_parts);
   }
 
   /* 
@@ -3353,13 +3353,13 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item **cond)
   {
     for (keynr= 0;  keynr < table->s->keys; keynr++)
     {
-      if (table->quick_keys.is_set(keynr) &&
-          table->quick_key_parts[keynr] == quick_key_parts)
+      if (table->opt_range_keys.is_set(keynr) &&
+          table->opt_range[keynr].key_parts == quick_key_parts)
       {
         uint i;
-        uint used_key_parts= table->quick_key_parts[keynr];
-        double quick_cond_selectivity= table->quick_rows[keynr] / 
-	                               table_records;
+        uint used_key_parts= table->opt_range[keynr].key_parts;
+        double quick_cond_selectivity= (table->opt_range[keynr].rows /
+                                        table_records);
         KEY *key_info= table->key_info + keynr;
         KEY_PART_INFO* key_part= key_info->key_part;
         /*
@@ -5777,7 +5777,7 @@ bool prepare_search_best_index_intersect(PARAM *param,
       continue;
     }
 
-    cost= table->quick_index_only_costs[(*index_scan)->keynr];
+    cost= table->opt_range[(*index_scan)->keynr].index_only_cost;
 
     idx_scan.add("cost", cost);
 
@@ -7188,7 +7188,7 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
     ha_rows best_rows = double2rows(intersect_best->out_rows);
     if (!best_rows)
       best_rows= 1;
-    set_if_smaller(param->table->quick_condition_rows, best_rows);
+    set_if_smaller(param->table->opt_range_condition_rows, best_rows);
     trp->records= best_rows;
     trp->index_scan_costs= intersect_best->index_scan_costs;
     trp->cpk_scan= cpk_scan;
@@ -7357,7 +7357,7 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
   trp->read_cost= total_cost;
   trp->records= records;
   trp->cpk_scan= NULL;
-  set_if_smaller(param->table->quick_condition_rows, records); 
+  set_if_smaller(param->table->opt_range_condition_rows, records);
 
   DBUG_PRINT("info",
              ("Returning covering ROR-intersect plan: cost %g, records %lu",
@@ -11083,11 +11083,11 @@ void SEL_ARG::test_use_count(SEL_ARG *root)
                         about range scan we've evaluated.
       mrr_flags   INOUT MRR access flags
       cost        OUT   Scan cost
+      is_ror_scan       is set to reflect if the key scan is a ROR (see
+                        is_key_scan_ror function for more info)
 
   NOTES
-    param->is_ror_scan is set to reflect if the key scan is a ROR (see
-    is_key_scan_ror function for more info)
-    param->table->quick_*, param->range_count (and maybe others) are
+    param->table->opt_range*, param->range_count (and maybe others) are
     updated with data of given key scan, see quick_range_seq_next for details.
 
   RETURN
@@ -11157,6 +11157,7 @@ ha_rows check_quick_select(PARAM *param, uint idx, bool index_only,
   if (param->table->pos_in_table_list->is_non_derived())
     rows= file->multi_range_read_info_const(keynr, &seq_if, (void*)&seq, 0,
                                             bufsize, mrr_flags, cost);
+  param->quick_rows[keynr]= rows;
   if (rows != HA_POS_ERROR)
   {
     ha_rows table_records= param->table->stat_records();
@@ -11164,30 +11165,30 @@ ha_rows check_quick_select(PARAM *param, uint idx, bool index_only,
     {
       /*
         For any index the total number of records within all ranges
-        cannot be be bigger than the number of records in the table
+        cannot be be bigger than the number of records in the table.
+        This check is needed as sometimes that table statistics or range
+        estimates may be slightly out of sync.
       */
       rows= table_records;
       set_if_bigger(rows, 1);
+      param->quick_rows[keynr]= rows;
     }
-    param->quick_rows[keynr]= rows;
     param->possible_keys.set_bit(keynr);
     if (update_tbl_stats)
     {
-      param->table->quick_keys.set_bit(keynr);
-      param->table->quick_key_parts[keynr]= param->max_key_parts;
-      param->table->quick_n_ranges[keynr]= param->range_count;
-      param->table->quick_condition_rows=
-        MY_MIN(param->table->quick_condition_rows, rows);
-      param->table->quick_rows[keynr]= rows;
-      param->table->quick_costs[keynr]= cost->total_cost();
+      param->table->opt_range_keys.set_bit(keynr);
+      param->table->opt_range[keynr].key_parts= param->max_key_parts;
+      param->table->opt_range[keynr].ranges= param->range_count;
+      param->table->opt_range_condition_rows=
+        MY_MIN(param->table->opt_range_condition_rows, rows);
+      param->table->opt_range[keynr].rows= rows;
+      param->table->opt_range[keynr].cost= cost->total_cost();
       if (param->table->file->is_clustering_key(keynr))
-	param->table->quick_index_only_costs[keynr]= 0;
+	param->table->opt_range[keynr].index_only_cost= 0;
       else
-        param->table->quick_index_only_costs[keynr]= cost->index_only_cost();
+        param->table->opt_range[keynr].index_only_cost= cost->index_only_cost();
     }
   }
-  else
-    param->quick_rows[keynr]= HA_POS_ERROR;
 
   /* Figure out if the key scan is ROR (returns rows in ROWID order) or not */
   enum ha_key_alg key_alg= param->table->key_info[seq.real_keyno].algorithm;

sql/opt_subselect.cc

@@ -2500,7 +2500,7 @@ bool optimize_semijoin_nests(JOIN *join, table_map all_table_map)
           double rows= 1.0;
           while ((tableno = tm_it.next_bit()) != Table_map_iterator::BITMAP_END)
             rows= COST_MULT(rows,
-			    join->map2table[tableno]->table->quick_condition_rows);
+			    join->map2table[tableno]->table->opt_range_condition_rows);
           sjm->rows= MY_MIN(sjm->rows, rows);
         }
         memcpy((uchar*) sjm->positions,

sql/rowid_filter.cc

@@ -110,10 +110,12 @@ Range_rowid_filter_cost_info::set_adjusted_gain_param(double access_cost_factor)
 void Range_rowid_filter_cost_info::init(Rowid_filter_container_type cont_type,
                                         TABLE *tab, uint idx)
 {
+  DBUG_ASSERT(tab->opt_range_keys.is_set(idx));
+
   container_type= cont_type;
   table= tab;
   key_no= idx;
-  est_elements= (ulonglong) (table->quick_rows[key_no]);
+  est_elements= (ulonglong) table->opt_range[key_no].rows;
   b= build_cost(container_type);
   selectivity= est_elements/((double) table->stat_records());
   a= avg_access_and_eval_gain_per_row(container_type);
@@ -134,8 +136,9 @@ double
 Range_rowid_filter_cost_info::build_cost(Rowid_filter_container_type cont_type)
 {
   double cost= 0;
+  DBUG_ASSERT(table->opt_range_keys.is_set(key_no));
 
-  cost+= table->quick_index_only_costs[key_no];
+  cost+= table->opt_range[key_no].index_only_cost;
 
   switch (cont_type) {
 
@@ -345,7 +348,7 @@ void TABLE::init_cost_info_for_usable_range_rowid_filters(THD *thd)
   uint key_no;
   key_map usable_range_filter_keys;
   usable_range_filter_keys.clear_all();
-  key_map::Iterator it(quick_keys);
+  key_map::Iterator it(opt_range_keys);
 
   /*
     From all indexes that can be used for range accesses select only such that
@@ -359,7 +362,7 @@ void TABLE::init_cost_info_for_usable_range_rowid_filters(THD *thd)
       continue;
     if (file->is_clustering_key(key_no))                              // !2
       continue;
-   if (quick_rows[key_no] >
+   if (opt_range[key_no].rows >
        get_max_range_rowid_filter_elems_for_table(thd, this,
                                                   SORTED_ARRAY_CONTAINER)) // !3
       continue;

sql/sql_delete.cc

@@ -492,7 +492,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   set_statistics_for_table(thd, table);
 
   table->covering_keys.clear_all();
-  table->quick_keys.clear_all();		// Can't use 'only index'
+  table->opt_range_keys.clear_all();
 
   select=make_select(table, 0, 0, conds, (SORT_INFO*) 0, 0, &error);
   if (unlikely(error))
@@ -518,7 +518,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   }
 
   /* If running in safe sql mode, don't allow updates without keys */
-  if (table->quick_keys.is_clear_all())
+  if (table->opt_range_keys.is_clear_all())
   {
     thd->set_status_no_index_used();
     if (safe_update && !using_limit)

sql/sql_update.cc

@@ -443,7 +443,7 @@ int mysql_update(THD *thd,
   
   /* Calculate "table->covering_keys" based on the WHERE */
   table->covering_keys= table->s->keys_in_use;
-  table->quick_keys.clear_all();
+  table->opt_range_keys.clear_all();
 
   query_plan.select_lex= thd->lex->first_select_lex();
   query_plan.table= table;
@@ -577,7 +577,7 @@ int mysql_update(THD *thd,
   }
 
   /* If running in safe sql mode, don't allow updates without keys */
-  if (table->quick_keys.is_clear_all())
+  if (table->opt_range_keys.is_clear_all())
   {
     thd->set_status_no_index_used();
     if (safe_update && !using_limit)

sql/table.cc

@@ -3976,6 +3976,15 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
                                                   sizeof(Field*)))))
     goto err;                                   /* purecov: inspected */
 
+  /* Allocate storage for range optimizer */
+  if (!multi_alloc_root(&outparam->mem_root,
+                        &outparam->opt_range,
+                        share->keys * sizeof(TABLE::OPT_RANGE),
+                        &outparam->const_key_parts,
+                        share->keys * sizeof(key_part_map),
+                        NullS))
+    goto err;
+
   outparam->field= field_ptr;
 
   record= (uchar*) outparam->record[0]-1;	/* Fieldstart = 1 */
@@ -5383,9 +5392,9 @@ void TABLE::init(THD *thd, TABLE_LIST *tl)
   range_rowid_filter_cost_info_ptr= NULL;
   range_rowid_filter_cost_info= NULL;
   vers_write= s->versioned;
-  quick_condition_rows=0;
+  opt_range_condition_rows=0;
   no_cache= false;
-  initialize_quick_structures();
+  initialize_opt_range_structures();
 #ifdef HAVE_REPLICATION
   /* used in RBR Triggers */
   master_had_triggers= 0;
@@ -7773,12 +7782,28 @@ void TABLE::restore_blob_values(String *blob_storage)
 
 bool TABLE::alloc_keys(uint key_count)
 {
-  key_info= (KEY*) alloc_root(&mem_root, sizeof(KEY)*(s->keys+key_count));
+  KEY *new_key_info;
+  key_part_map *new_const_key_parts;
+  DBUG_ASSERT(s->tmp_table == INTERNAL_TMP_TABLE);
+
+  if (!multi_alloc_root(&mem_root,
+                        &new_key_info, sizeof(*key_info)*(s->keys+key_count),
+                        &new_const_key_parts,
+                        sizeof(*new_const_key_parts)*(s->keys+key_count),
+                        NullS))
+    return TRUE;
   if (s->keys)
-    memmove(key_info, s->key_info, sizeof(KEY)*s->keys);
-  s->key_info= key_info;
+  {
+    memmove(new_key_info, s->key_info, sizeof(*key_info) * s->keys);
+    memmove(new_const_key_parts, const_key_parts,
+            s->keys * sizeof(const_key_parts));
+  }
+  s->key_info= key_info= new_key_info;
+  const_key_parts= new_const_key_parts;
+  bzero((char*) (const_key_parts + s->keys),
+        sizeof(*const_key_parts) * key_count);
   max_keys= s->keys+key_count;
-  return !(key_info);
+  return FALSE;
 }
 
 
@@ -9898,20 +9923,18 @@ bool TABLE::export_structure(THD *thd, Row_definition_list *defs)
 
 /*
   @brief
-    Initialize all the quick structures that are used to stored the
+    Initialize all the opt_range structures that are used to stored the
     estimates when the range optimizer is run.
-  @details
-    This is specifically needed when we read the TABLE structure from the
-    table cache. There can be some garbage data from previous queries
-    that need to be reset here.
+    As these are initialized by the range optimizer for all index
+    marked in opt_range_keys, we only mark the memory as undefined
+    to be able to find wrong usage of data with valgrind or MSAN.
 */
 
-void TABLE::initialize_quick_structures()
+void TABLE::initialize_opt_range_structures()
 {
-  bzero(quick_rows, sizeof(quick_rows));
-  bzero(quick_key_parts, sizeof(quick_key_parts));
-  bzero(quick_costs, sizeof(quick_costs));
-  bzero(quick_n_ranges, sizeof(quick_n_ranges));
+  TRASH_ALLOC(&opt_range_keys, sizeof(opt_range_keys));
+  TRASH_ALLOC(opt_range, s->keys * sizeof(*opt_range));
+  TRASH_ALLOC(const_key_parts, s->keys * sizeof(*const_key_parts));
 }
 
 /*

sql/table.h

@@ -1257,8 +1257,7 @@ struct TABLE
     Map of keys that can be used to retrieve all data from this table 
     needed by the query without reading the row.
   */
-  key_map covering_keys;
-  key_map quick_keys, intersect_keys;
+  key_map covering_keys, intersect_keys;
   /*
     A set of keys that can be used in the query that references this
     table.
@@ -1340,28 +1339,29 @@ struct TABLE
   /* The estimate of the number of records in the table used by optimizer */ 
   ha_rows used_stat_records;
 
+  key_map opt_range_keys;
   /* 
-    For each key that has quick_keys.is_set(key) == TRUE: estimate of #records
-    and max #key parts that range access would use.
+    The following structure is filled for each key that has
+    opt_range_keys.is_set(key) == TRUE
   */
-  ha_rows	quick_rows[MAX_KEY];
-  uint          quick_key_parts[MAX_KEY];
-
-  double 	quick_costs[MAX_KEY];
-  /*
-    If there is a range access by i-th index then the cost of
-    index only access for it is stored in quick_index_only_costs[i]
-  */
-  double 	quick_index_only_costs[MAX_KEY];
-
+  struct OPT_RANGE
+  {
+    uint        key_parts;
+    uint        ranges;
+    ha_rows     rows;
+    double      cost;
+    /*
+      If there is a range access by i-th index then the cost of
+      index only access for it is stored in index_only_costs[i]
+    */
+    double      index_only_cost;
+  } *opt_range;
   /* 
-    Bitmaps of key parts that =const for the duration of join execution. If
-    we're in a subquery, then the constant may be different across subquery
-    re-executions.
+     Bitmaps of key parts that =const for the duration of join execution. If
+     we're in a subquery, then the constant may be different across subquery
+     re-executions.
   */
-  key_part_map  const_key_parts[MAX_KEY];
-
-  uint    quick_n_ranges[MAX_KEY];
+  key_part_map *const_key_parts;
 
   /* 
     Estimate of number of records that satisfy SARGable part of the table
@@ -1371,7 +1371,7 @@ struct TABLE
     that will pass the table condition (condition that depends on fields of 
     this table and constants)
   */
-  ha_rows       quick_condition_rows;
+  ha_rows       opt_range_condition_rows;
 
   double cond_selectivity;
   List<st_cond_statistic> *cond_selectivity_sampling_explain;
@@ -1637,7 +1637,7 @@ struct TABLE
   bool is_filled_at_execution();
 
   bool update_const_key_parts(COND *conds);
-  void initialize_quick_structures();
+  void initialize_opt_range_structures();
 
   my_ptrdiff_t default_values_offset() const
   { return (my_ptrdiff_t) (s->default_values - record[0]); }