I have a server with 12GB RAM, and max_heap_table_size in my.cnf is set to 6GB. ("max_heap_table_size=6442450944"). I restarted the MySQL server after setting this.
The trouble is, whenever my table gets to just 2GB during inserts I get error "table full". Why is it not letting me add more than 2GB worth of data? (The 2GB figure is what is shown as the size in phpMyAdmin)
A 32 bit MySQL server (or any 32 bit application for that matter) only have 2-3Gb(Depending on the OS, etc.) of virtual memory available, and thus can't address more memory. You need a 64 bit OS, and a 64 bit MySQL server to take advantage of more memory.
Related
Why MySQL server took time compare than MySQL inside wamp ?
Machine 1 installed MySQL 5.6.17(inside the wamp)
Machine 2 installed MySQL 5.7.24(separate server)
Both machines are same configuration and same OS.
I imported same DB dump file to Machine1 and Machine2.
Now I execute query (the query get data from 6 join tables) and return 400 rows.
Took time:
Machine 1 (5.6.17) inside wamp- Below 30 sec's
Machine 2 (5.7.24) - Morethan 230 sec's
Shall I use MySQL(wamp) instead of MySQL server?
I think MySQL server need to increase Innodb_bufferpool_size on my.ini which located from C;\Program Data (Default hidden folder)
Default Innodb_bufferpool_size is 8M
innodb_buffer_pool_size: This is a very important setting to look immediate after the installation using InnoDB. The InnoDB is the buffer pool where the data is indexed the cached, which has a very large possible size that will make sure and use the memory no the disk space for most of the read-write operations, generally the size of InnoDB values are 5-6GB for 8GB RAM.
Fix: Increase innodb_buffer_pool_size
innodb_buffer_pool_size=356M
i am running a wordpress website with on VULTR VPS 1GB RAM SSD,
my website has 20000+ posts and now its even slow on 4GB RAM VPS i think this is just for max mysql load right? im just noob in programming, please figure this out for me , how to load my website faster with this 20000+ posts or what to configure in the server ?
You provided very little info so it's impossible to diagnose the problem.
First you should monitor the system: CPU, memory, I/O and check if any of these are close to the limits.
Second you should monitor the database: have you access to the DB server? have you access to any monitoring facilities?
If the performance decreased when the post increased it's possible that the problem is the DB but you must understand what: a missing index? an outdated statistic?
Anyway nothing can be said without a proper monitoring
1GB RAM -- that is tiny by today's standards.
Check for swapping. That is a killer for MySQL.
Which "Engine" are your tables? (Do SHOW CREATE TABLE for a typical table.)
If ENGINE=MyISAM, look in my.cnf for key_buffer_size; it should be something like 50M. (400M for 4GB of RAM)
If ENGINE=InnoDB, look in my.cnf for innodb_buffer_pool_size; it should be something like 150M (1200M for 4GB of RAM) and key_buffer_size should be about 10M.
If your settings are significantly smaller than those, that is likely to be the problem. To double check the settings, do (from phpmyadmin, mysql commandline tool, or wherever):
SHOW VARIABLES LIKE '%buffer%';
I am a MYSQL beginner and I want to allocate more memory to MYSQL.
My machine is Windows 7 64 bit OS with 12GB RAM and Mysql version is 5.6.
Any one can give me the commands to increase memory for MYSQL.
there is a file called my.ini for mysql(windows) which contains
'innodb_buffer_pool_size=M'
(if no such field you can add explicitly under mysqld tag) where M is MB you can use G for GB increasing this value will solve your purpose and remember to verify using query
show variables like '%innodb_buffer_pool_size%';
I have mysql running on a windows machine with 3GB usable RAM and a single core. However, when I allocate more than 1GB to innodb_buffer_pool_size, I get an error saying
'mysql service cannot be started' because memory could not be
allocated to the innodb_buffer_pool.
I want to allocate atleast 2 GB to improve my performance. Any ideas/suggestions as to how I can achieve this. All my other mysql variable values are quite small (16M - 64M).
Very very late answer but I had the same problem and found this solution:
In 32 bit Windows w/ 4 Gb RAM, not all 4 Gb RAM is available for application space. In reality there is a 2Gb/2Gb split between userland and kernelspace.
The solution already given (and hopefully implemented) is to use a 64 bit OS along with 64 bit version of MySQL.
This post contains an idea to extend userland memory to 3Gb via a modification to the MySQL binary.
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?