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  1. MariaDB Server
  2. MDEV-7947

my_charset_same: strcmp() takes 0.37% in OLTP RO

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.1
    • Fix Version/s: 10.5.5
    • Component/s: Performance
    • Labels:
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      Description

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

      Call graphs:

      -   0.37%  mysqld  libc-2.15.so
         - __strcmp_sse42
            + 43.10% Protocol::store_string_aux(char const*, unsigned long, charset_info_st const*, charset_info_st const*)
            + 27.26% ha_innobase::change_active_index(unsigned int)
            + 20.46% open_table(THD*, TABLE_LIST*, Open_table_context*)
            + 7.66% ha_innobase::records_in_range(unsigned int, st_key_range*, st_key_range*)
            + 1.52% Item::set_name(char const*, unsigned int, charset_info_st const*)

      Protocol::store_string_aux() calls my_charset_same(), which does strcmp(). This can be optimized out.

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            Assignee:
            monty Michael Widenius
            Reporter:
            svoj Sergey Vojtovich
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              Updated:
              Resolved: