maria-discuss team mailing list archive

["Ling, Andy" <Andy.Ling@xxxxxxxxxxxxxxx>]

MariaDB is still significantly slower.


From: Roberto Spadim [mailto:roberto@xxxxxxxxxxxxx]
Sent: Mon 01 June 2020 18:33
To: Ling, Andy <Andy.Ling@xxxxxxxxxxxxxxx>
Cc: Mailing-List mariadb <maria-discuss@xxxxxxxxxxxxxxxxxxx>
Subject: [EXTERNAL] Re: [Maria-discuss] Poor performance compared to MySQL


External Message:Use caution before opening links or attachments
what happen when comparing myisam-myisam?

Em seg., 1 de jun. de 2020 às 12:51, Ling, Andy <Andy.Ling@xxxxxxxxxxxxxxx<mailto:Andy.Ling@xxxxxxxxxxxxxxx>> escreveu:
I am looking at switching from MySQL to MariaDB and have been comparing the performance of the two.
I am using the same databases on the same Windows machine and running queries using MySQL and MariaDB
and I am finding that MariaDB is 6 times slower. A query that takes 5 seconds on MySQL is taking 28 seconds on MariaDB.

I am hoping I have some configuration wrong, so I looking for some help to work out what needs changing.

One of the problem queries is a join between two tables. Analyzing the query gives..

ANALYZE FORMAT=JSON SELECT r.rushid FROM rushes r LEFT JOIN browse b ON r.rushID = b.rushID WHERE b.rushID IS NULL AND r.updated < NOW() - INTERVAL 1 DAY;
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------+
| ANALYZE
                                                                                       |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------+
| {
  "query_block": {
    "select_id": 1,
    "r_loops": 1,
    "r_total_time_ms": 107974,
    "table": {
      "table_name": "r",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 784286,
      "r_rows": 784286,
      "r_total_time_ms": 245.5,
      "filtered": 100,
      "r_filtered": 100,
      "attached_condition": "r.updated < '2020-05-31 16:35:59'"
    },
    "table": {
      "table_name": "b",
      "access_type": "ref",
      "possible_keys": ["rushid_start", "rushid"],
      "key": "rushid",
      "key_length": "96",
      "used_key_parts": ["rushID"],
      "ref": ["quentin_v3afp.r.rushID"],
      "r_loops": 784286,
      "rows": 10,
      "r_rows": 1,
      "r_total_time_ms": 106252,
      "filtered": 100,
      "r_filtered": 100,
      "attached_condition": "trigcond(b.rushID is null)",
      "using_index": true,
      "not_exists": true
    }
  }
} |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------+
1 row in set (1 min 48.244 sec)

The table has been converted to the Aria engine from MyISAM. The my.ini file has had the following added/changed..

#Not using MyISAM so save memory
key_buffer_size=64k

#Setting to improve Aria performance
aria_pagecache_buffer_size=4007M

tmp_table_size=35M
max_heap_table_size=35M



Thanks for any help.

Andy Ling


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--
Roberto Spadim
SPAEmpresarial - Software ERP/Scada
Eng. Automação e Controle, Eng. Financeira