MySQL Forums
Forum List  »  Performance

Re: MySQL became too slowly when using O_DIRECT
Posted by: Jerry Lin
Date: June 08, 2018 04:00AM

Hi ,

My server is Ubuntu 16.04 and MySQL 5.7.22
This server is a VM that has 2 cores and 8G ram.
This server has a SATA and a SSD disk.

I run MySQL on SSD ,the tps of o_direct and fsync almost the same ,but I run MySQL on SATA ,the tps will get big gap.

I used sysbench 0.4.12 to run my test.
My test script as below:
sysbench --test=oltp --db-driver=mysql --mysql-table-engine=innodb --mysql-host= --mysql-port=3306 --mysql-db=sysbench --oltp-table-size=20000000 --mysql-user=dba --mysql-password=dba --max-time=30 --max-requests=0 --num-threads=16 run

My configuration as below:
user = mysql
port = 3306
basedir = /usr/local/mysql
datadir = /var/lib/mysql/data
socket = /var/lib/mysql/mysql.sock
pid-file = /var/lib/mysql/
character-set-server = utf8mb4
skip_name_resolve = 1
log-error = /var/lib/mysql/error.log
server-id = 83
#log-bin = /var/lib/mysql/binlog/mydbsrv4-bin
gtid_mode = on
enforce_gtid_consistency = 1
binlog_format = row
master_info_repository = TABLE
relay_log_info_repository = TABLE
#slave-parallel-workers = 2
#slave-preserve-commit-order = 1
#slave-parallel-type = LOGICAL_CLOCK
#innodb_additional_mem_pool_size = 16M
innodb_buffer_pool_size = 2048M
innodb_buffer_pool_instances = 8
innodb_buffer_pool_load_at_startup = 1
innodb_buffer_pool_dump_at_shutdown = 1
innodb_data_file_path = ibdata1:1G:autoextend
innodb_flush_log_at_trx_commit = 1
innodb_log_buffer_size = 32M
innodb_log_file_size = 256M
innodb_log_files_in_group = 2

If you need more information ,please tell me what kind of information you should know ,thank you.

Options: ReplyQuote

Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.