Slow writing database using `mysqldump`

I am trying to automate the mysql dump of all databases with Azure Database for MySQL Server. Current database size:

mysql> SELECT table_schema "DB Name", Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
       FROM information_schema.tables GROUP  BY table_schema;
+--------------------+---------------+
| DB Name            | DB Size in MB |
+--------------------+---------------+
| db1                |         278.3 |
| db2                |          51.8 |
| information_schema |           0.2 |
| mysql              |           8.9 |
| performance_schema |           0.0 |
| db3                |          43.3 |
| sys                |           0.0 |
+--------------------+---------------+
7 rows in set (31.80 sec)

I have a python script on another virtual machine that calls mysqldumpto upload all of them to a file. However, I ran into a problem with db1. It is flushed to the file, but it is very slow, less than ~ 4 MB in 30 minutes. However, db2they are db3reset almost immediately, in seconds.

I tried all of the following options and combinations to see if the writing speed has changed, but this is not the case:

--compress
--lock-tables (true / false)
--skip-lock-tables
--max-allowed-packet (512M)
--quick
--single-transaction
--opt

Currently, I don’t even use a script, I just run the commands in the shell with the same result.

mysqldump -h <host> -P <port> -u'<user>' -p'<password>' db1 > db1.sql

db1 has ~ 500 tables.

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Source: https://habr.com/ru/post/1684925/


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