I have very limited resources (RAM) on my server (Debian lenny) and I need to install mySQL server, it will not be extensively used. I installed apt-get install mysql-server before but it was taking about 150MB of RAM and I am looking for alternative servers, are there any, I couldn't find anything.
Thank you in advance!
It can certainly be tuned to use less ram than the default. In particular, Debian may ship it with a configuration which is more suitable for a typical server-grade machine.
If you feel the need to run MySQL on a very memory-constrained platform, consider tuning its memory usage as described here: How MySQL Uses Memory
You probably want to use InnoDB; the most important thing to tune is to make your innodb_buffer_pool a sensible size (There are other InnoDB buffers you may want to tune too; read its documentation).
If you aren't using MyISAM, reduce its key_buffer_size to a small value (say 4M). MyISAM can't be disabled as it's used internally.
If you aren't using InnoDB, turn it off entirely.
Related
I'm trying to optimise the Digital Ocean droplet that my Laravel web app is running on, and have noticed that MySQL is constantly using ~50% of its 1GB RAM. By far the most common and well-attested method for decreasing MySQL's memory footprint is to disable its Performance Schema feature by setting performance_schema = 0 in /etc/mysql/my.cnf.
However, no answer I've seen yet makes any mention of what exactly this feature does, why it's enabled by default, and the implications of disabling it. To me it seems too be good to be true, and while I'm all for optimisation, I also don't want to compromise the integrity of my web app's server.
The performance_schema is for monitoring and instrumenting the MySQL Server. Many types of monitoring tools may depend on it. I won't describe the specific events it monitors, because that's in the manual.
You can run MySQL Server without the performance_schema enabled, but monitoring will be compromised. If you disable monitoring, you will not be able to diagnose performance problems or resource usage.
The IT industry is becoming increasingly aware that monitoring is an important feature of servers and infrastructure. I don't think it's a good tradeoff to disable the performance_schema in MySQL Server to gain a mere 512MB of memory. If you are that constrained on memory, then you should reconsider if MySQL Server is the right technology choice for your platform.
I have setup with Linux, Debian Jessie with Mysql 5.7.13 installed.
I have set following settings in
my.cnf: default_storage_engine= innodb, innodb_buffer_pool_size= 44G
When I start MySQL I manually set max_connections with SET GLOBAL max_connections = 1000;
Then I trigger my loadtest that sends a lot of traffic to the DB server which mostly consists of slow/bad queries.
The result I expected was that I would reach close to 1000 connections but somehow MySQL limits it to 462 connections and I can not find the setting that is responsible for this limit. We are not even close to maxing out the CPU or Memory.
If you have any idea or could point me in a direction where you think the error might be it would be really helpful.
What loadtest did you use? Are you sure that it can utilize about thousands of connections?
You may maxing out your server resources in the disk IO area, especially if you're talking about lot of slow/bad queries. Did you check for disk utilization on your server?
Even if your InnoDB pool size is large your DB still need to read your DB to the cache first, and if your entire DB is large it will not help you.
I can recommend you to perform such a test once more time and track your disk performance during loadtest using iostat or iotop utility.
Look here for more examples of the server performance troubleshooting.
I found the issue, it was du to limitation of Apache server, there is a "hidden" setting inside /etc/apache2/mods-enabled/mpm_prefork.conf which will overwrite setting inside /etc/apache2/apache2.conf
Thank you!
I have a mysql server in linux platform. I need to do performance tuning in that mysql server which is innodb engine.I want know the manual configuration in my.cnf file. so, what are all the important innodb parameters to be configure ? Because innodb and myisam engines are having different tuning operations. please tell some useful things to do
I would recommend using MySQL Tuner
This is good starting point for MySQL performance tuning.
You should also be running some kind of monitoring software that is able to graph
you MySQL health. This is vastly helpful when the performance trouble comes in.
I would recommend you munin with the MySQL plugins.
Regards -- Luke
Recently we changed app server of our rails website from mongrel to passenger [with REE and Rails 2.3.8]. The production setup has 6 machines pointing to a single mysql server and a memcache server. Before each machine had 5 mongrel instance. Now we have 45 passenger instance as the RAM in each machine is 16GB with 2, 4 core cpu. Once we deployed this passenger set up in production. the Website became so slow. and all the request starting to queue up. And eventually we had to roll back.
Now we suspect that the cause should be the increased load to the Mysql server. As before there where only 30 mysql connection and now we have 275 connection. The mysql server has the similar set up as our website machine. bUt all the configs were left to the defaul limit. The buffer_pool_size is only 8 mb though we have 16GB ram. and number of Concurrent threads is 8.
Will this increased simultaneous connection to mysql would have caused mysql to respond slowly than when we had only 30 connections? If so, how can we make mysql perform better with 275 simultaneous connection in place.
Any advice greatly appreciated.
UPDATE:
More information on the mysql server:
RAM : 16GB CPU: two processors each having 4 cores
Tables are innoDB. with only default innodb config values.
Thanks
An idle MySQL connection uses up a stack and a network buffer on the server. That is worth about 200 KB of memory and zero CPU.
In a database using InnoDB only, you should edit /etc/sysctl.conf to include vm.swappiness = 0 to delay swapping out processes as long as possible. You should then increase innodb_buffer_pool_size to about 80% of the systems memory assuming a dedicated database server machine. Make sure the box does not swap, that is, VSIZE should not exceed system RAM.
innodb_thread_concurrency can be set to 0 (unlimited) or 32 to 64, if you are a bit paranoid, assuming MySQL 5.5. The limit is lower in 5.1, and around 4-8 in MySQL 5.0. It is not recommended to use such outdated versions of MySQL in a machine with 8 or 16 cores, there are huge improvements wrt to concurrency in MySQL 5.5 with InnoDB 1.1.
The variable thread_concurrency has no meaning inside a current Linux. It is used to call pthread_setconcurrency() in Linux, which does nothing. It used to have a function in older Solaris/SunOS.
Without further information, the cause for your performance problems cannot be determined with any security, but the above general advice may help. More general advice geared at my limited experience with Ruby can be found in http://mysqldump.azundris.com/archives/72-Rubyisms.html That article is the summary of a consulting job I once did for an early version of a very popular Facebook application.
UPDATE:
According to http://pastebin.com/pT3r6A9q , you are running 5.0.45-community-log, which is awfully old and does not perform well under concurrent load. Use a current 5.5 build, it should perform way better than what you have there.
Also, fix the innodb_buffer_pool_size. You are going nowhere with only 8M of pool here.
While you are at it, innodb_file_per_table should be ON.
Do not switch on innodb_flush_log_at_trx_commit = 2 without understanding what that means, but it may help you temporarily, depending on your persistence requirements. It is not a permanent solution to your problems in any way, though.
If you have any substantial kind of writes going on, you need to review the innodb_log_file_size and innodb_log_buffer_size as well.
If that installation is earning money, you dearly need professional help. I am no longer doing this as a profession, but I can recommend people. Contact me outside of Stack Overflow if you want.
UPDATE:
According to your processlist, you have very many queries in state Sending data. MySQL is in this state when a query is being executed, that is, the main interior Join Loop/Query Execution loop is busy. SHOW ENGINE INNODB STATUS\G will show you something like
...
--------------
ROW OPERATIONS
--------------
3 queries inside InnoDB, 0 queries in queue
...
If that number is larger than say 4-8 (inside InnoDB), 5.0.x is going to have trouble. 5.5.x will perform a lot better here.
Regarding the my.cnf: See my previous comments on your InnoDB. See also my comments on thread_concurrency (without innodb_ prefix):
# On Linux, this does exactly nothing.
thread_concurrency = 8
You are missing all innodb configuration at all. Assuming that you ARE using innodb tables, you are not performing well, no matter what you do.
As far as I know, it's unlikely that merely maintaining/opening the connections would be the problem. Are you seeing this issue even when the site is idle?
I'd try http://www.quest.com/spotlight-on-mysql/ or similar to see if it's really your database that's the bottleneck here.
In the past, I've seen basic networking craziness lead to behaviour similar to what you describe - someone had set up the new machines with an incorrect submask.
Have you looked at any of the machine statistics on the database server? Memory/CPU/disk IO stats? Is the database server struggling?
How good it'd be to have 64 bit MySQL on 64 bit Linux ofcouse?
Presently I have 32bit Mysql / OS but 64bit hardware.
Shall I consider upgrade? What advantages do I have?
You will get the main advantage of 64bit software - you will be able to address more RAM
What advantages do I have?
Potentially bigger in-memory caches. And big caches can really help database performance ... in some cases. However, I've also noticed evidence that suggests that there is a limit to which application caches help, and that in some situations a OS level file caches work better at reducing disc IO delays.
For some hints on how 64bit MySQL (with appropriate tuning) might help, read How MySQL Uses Memory from the MySQL manual.