Ok, some debugging ideas:

Let's investigate if the number of times we're calling the storage engine code.

What would be useful information to have: Can you run

show global status like '%handler%';

Both for MariaDB and MySQL (both 5.5 versions and 10.4 version), before and after the problematic query.

(In total you should have 6 outputs, 4 for MariaDB (5.5 and 10.4 before and after the query) and 2 for MySQL (before and after the query).

We should compare how big of an increase we see for both servers. This may give us some direction if we see a big difference between the two. Additionally, if you can share the data in any way so I can try to reproduce the problem that may help speed things up.

Vicențiu

Well I’ve had a go. Using MariaDB 5.5.68 and MyISAM tables I get times very similar to MySQL

 

Some more definitive timings all on the same hardware…

 

MySQL 5.5 MyISAM

 

mysql> 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;

+----------------------------------+

| rushid                           |

+----------------------------------+

| 4de1e340d664dd87c4afda2c27f700a8 |

| 455166dd2cefff65f578aa333f7a5581 |

| 44f02723e901d2e958c58b9813ebaeae |

+----------------------------------+

3 rows in set (3.63 sec)

 

 

MariaDB 5.5.68 MyISAM

 

MariaDB [quentin_v3]> 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;

+----------------------------------+

| rushid                           |

+----------------------------------+

| 4de1e340d664dd87c4afda2c27f700a8 |

| 455166dd2cefff65f578aa333f7a5581 |

| 44f02723e901d2e958c58b9813ebaeae |

+----------------------------------+

3 rows in set (3.01 sec)

 

MariaDB 10.4.2 MyISAM

 

MariaDB [quentin_v3]> 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;

+----------------------------------+

| rushid                           |

+----------------------------------+

| 4de1e340d664dd87c4afda2c27f700a8 |

| 455166dd2cefff65f578aa333f7a5581 |

| 44f02723e901d2e958c58b9813ebaeae |

+----------------------------------+

3 rows in set (12.890 sec)

 

MariaDB 10.4.2 Aria

 

MariaDB [quentin_v3]> 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;

+----------------------------------+

| rushid                           |

+----------------------------------+

| 4de1e340d664dd87c4afda2c27f700a8 |

| 455166dd2cefff65f578aa333f7a5581 |

| 44f02723e901d2e958c58b9813ebaeae |

+----------------------------------+

3 rows in set (16.268 sec)

 

So Aria is the slowest, but MariaDB 10 MyISAM is still a long way behind 5.5

 

Regards

 

Andy Ling

 

 

 

 

From: Vicențiu Ciorbaru [mailto:vicentiu@mariadb.org]
Sent: Tue 02 June 2020 13:18
To: Ling, Andy <Andy.Ling@grassvalley.com>
Cc: Mailing-List mariadb <maria-discuss@lists.launchpad.net>
Subject: [EXTERNAL] Re: [Maria-discuss] Poor performance compared to MySQL

 

External Message:Use caution before opening links or attachments

I don't really know what might have caused the slowdown. I'll ask around to see if any ideas come up.

I know this might be a bit tedious for you, but can you try with the latest MariaDB 5.5 and see if you get the same bad performance? You'll probably have to set-up a new datadir from the MySQL deployment.

 

MariaDB 5.5 should be very similar to MySQL 5.5. If we can narrow it down to a particular major version upgrade, it will be easier to track down where the slowdown happened. Probably analyzing performance logs could also hint towards a solution, but I have limited experience handling those.

 

Vicențiu

 

On Tue, 2 Jun 2020 at 14:12, Ling, Andy <Andy.Ling@grassvalley.com> wrote:

MariaDB is 10.4.12

 

MySQL is 5.5.34 – pretty old I know.

 

Regards

 

Andy Ling

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