[Optimization] Remove redundant pages allocations and frees

Tencent · Dec 2, 2020 · 4c10388 · 4c10388
1 parent 58e2751
commit 4c10388
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Showing 5 changed files with 15 additions and 5 deletions.
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
@@ -732,6 +732,7 @@ THD::THD(my_thread_id id, bool is_wsrep_applier, bool skip_global_sys_var_lock)
   spider_slow_query_num = 0;
   spider_current_partition_num = 0;
   spider_features_type = 0;
+  spider_const_index_read = FALSE;
   kill_self = FALSE;
 
   file_id = 0;

diff --git a/sql/sql_class.h b/sql/sql_class.h
@@ -2438,6 +2438,7 @@ class THD :public Statement,
   ulong current_global_server_version;
   bool is_support_ddl_by_ctl; // equal to tdbctl_is_ddl_by_ctl(thd,lex)
   bool do_ddl_by_ctl; // must do tcadmin_execute_command
+  bool spider_const_index_read; // const or system join type in spider
 
   // Process indicator
   struct {

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
@@ -7014,6 +7014,7 @@ void THD::reset_for_next_command(bool do_clear_error) {
   thd->spider_current_partition_num = 0;
   thd->spider_features_type = 0;
   thd->current_global_server_version = get_modify_server_version();
+  thd->spider_const_index_read = FALSE;
 
   DBUG_PRINT("debug", ("is_current_stmt_binlog_format_row(): %d",
                        is_current_stmt_binlog_format_row()));

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
@@ -17571,6 +17571,8 @@ static int join_read_const(JOIN_TAB *tab) {
     if (cp_buffer_from_ref(tab->join->thd, table, &tab->ref))
       error = HA_ERR_KEY_NOT_FOUND;
     else {
+      if (table->file->is_spider_storage_engine())
+        tab->join->thd->spider_const_index_read = TRUE;
       error = table->file->ha_index_read_idx_map(
           table->record[0], tab->ref.key, (uchar *)tab->ref.key_buff,
           make_prev_keypart_map(tab->ref.key_parts), HA_READ_KEY_EXACT);

diff --git a/storage/spider/spd_db_conn.cc b/storage/spider/spd_db_conn.cc
@@ -3034,11 +3034,16 @@ int spider_db_store_result(ha_spider *spider, int link_idx, TABLE *table) {
     SPIDER_DB_ROW *tmp_row;
     uint field_count = current->result->num_fields();
     SPIDER_POSITION *position;
-    longlong page_size =
-        !result_list->quick_page_size ||
-                result_list->limit_num < result_list->quick_page_size
-            ? result_list->limit_num
-            : result_list->quick_page_size;
+    longlong page_size = 0LL;
+    if (thd->spider_const_index_read) {
+      /* only one row for const index read */
+      page_size = 1;
+    } else {
+      page_size = !result_list->quick_page_size ||
+                          result_list->limit_num < result_list->quick_page_size
+                      ? result_list->limit_num
+                      : result_list->quick_page_size;
+    }
     int roop_count = 0;
     current->field_count = field_count;
     if (!(position = (SPIDER_POSITION *)spider_bulk_malloc(