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  1. MariaDB Server
  2. MDEV-7966

Item::real_item() takes 0.12% in OLTP RO

Details

    • Bug
    • Status: Open (View Workflow)
    • Minor
    • Resolution: Unresolved
    • 10.1(EOL)
    • 10.2(EOL)
    • None
    • None

    Description

      Data comes from Sandy Bridge system running sysbench OLTP RO in 1 thread against 1 table.

      Call graphs:

      -   0.12%  mysqld  mysqld
         - Item::real_item()
            + 29.39% Item_func::setup_args_and_comparator(THD*, Arg_comparator*)
            + 20.40% update_ref_and_keys(THD*, st_dynamic_array*, st_join_table*, unsigned int, Item*, unsigned long long, st_select_lex*, st_sargable_param**) [clone .isra.253]
            + 13.81% add_key_fields(JOIN*, key_field_t**, unsigned int*, Item*, unsigned long long, st_sargable_param**)
            + 8.36% SQL_SELECT::test_quick_select(THD*, Bitmap<64u>, unsigned long long, unsigned long long, bool, bool, bool)
            + 8.17% Item_func::fix_fields(THD*, Item**)
            + 3.35% create_sort_index(THD*, JOIN*, st_order*, unsigned long long, unsigned long long, bool)
            + 3.34% JOIN::prepare_stage2()
            + 3.34% JOIN::exec_inner()
            + 2.73% Item_func::compile(bool (Item::*)(unsigned char**), unsigned char**, Item* (Item::*)(unsigned char*), unsigned char*)
            + 2.48% get_mm_tree(RANGE_OPT_PARAM*, Item**)
            + 1.90% Item::compile(bool (Item::*)(unsigned char**), unsigned char**, Item* (Item::*)(unsigned char*), unsigned char*)
            + 1.51% make_join_statistics(JOIN*, List<TABLE_LIST>&, st_dynamic_array*)

      This is virtual method which can't be inlined. Most time spent for function call convention. Check if we can revoke it's virtual status.

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            bar Alexander Barkov
            svoj Sergey Vojtovich
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            Dates

              Created:
              Updated:

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