RE: MySQL 4.0.13 Memory problem under heavy load
Keep in mind that Linux will allocate nearly all of its free RAM to the buffer cache as the kernel opens and reads files to increase filesystem performance (cat /proc/meminfo and look at the "buffers" row) So, lack of free RAM may not mean what you think it means. As for the "too many connections" issues, take a look at the connections table (mysqladmin proc, or show processlist from the mysql command prompt). You may need to raise the connection limit even further. --Michael > -Original Message- > From: Kayra Otaner [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 20, 2003 3:57 PM > To: [EMAIL PROTECTED] > Subject: MySQL 4.0.13 Memory problem under heavy load > > > Hi all, > > I want to get your opinions on how to increase available/free > memory and performance on a heavy volume database server. > > I have MySQL 4.0.13 running on RH 7.2 replicated to another > RH 7.2 using same MySQL version. Recently our master database > server (2 AMD Cpu + 2Gb memory + 2Gb swap > space) started to suffer from memory outages because of > heavy load. During day available free memory is changing from > 200Mb to 5Mb and when available memory reaches to 5Mb MySQL > starts to give 'Too many connections' messages. Db server is > working with 45-70 query/second and more than 25,712 > connection per hour. There are active 10-13 threads serving databases. > > To increase available free memory I've did the following : > 1- Optimized all tables > 2- Removed unneccessary/old indexes > 3- Moved unused databases to replication server > 4- Increased key_buffer_size from 8Mb to 128Mb > 5- Have increased max_connection from 100 to 150 > 6- Have increased thread_cache to 5 > > This changes helped a bit but still memory is a problem for > MySQL. What should I do to prevent 'too many connections' > messages and have more memory available on database servers? > Should I remove more indexes from tables? Should I increase > key_buffer_size to 256Mb or more? Key_buffer_size doesn't > look like a problem since key efficiency looks 100% most of the time. > > > Thank you for your time > > Kayra Otaner > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/mysql?> [EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL 4.0.13 Memory problem under heavy load
In the last episode (Aug 20), Kayra Otaner said: > I want to get your opinions on how to increase available/free memory and > performance on a heavy volume database server. > > I have MySQL 4.0.13 running on RH 7.2 replicated to another RH 7.2 using > same MySQL version. > Recently our master database server (2 AMD Cpu + 2Gb memory + 2Gb swap > space) started to suffer from memory outages because of heavy load. > During day available free memory is changing from 200Mb to 5Mb and when > available memory reaches to 5Mb MySQL starts to give 'Too many > connections' messages. Db server is working with 45-70 query/second and I don't think those two are related. After an hour of operation, it's expected to have zero "Free" memory; unix uses unused memory as disk cache, so Free memory is wasted memory. More important questions are: Are you swapping? and What is the current memory usage of mysql? -- Dan Nelson [EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL 4.0.13 Memory problem under heavy load
I would run the DB on a RAMDisk http://www.ibiblio.org/mdw/linuxfocus/English/November1999/article124.html Anyone else? Martin - Original Message - From: "Kayra Otaner" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, August 20, 2003 3:56 PM Subject: MySQL 4.0.13 Memory problem under heavy load > Hi all, > > I want to get your opinions on how to increase available/free memory and > performance on a heavy volume database server. > > I have MySQL 4.0.13 running on RH 7.2 replicated to another RH 7.2 using > same MySQL version. > Recently our master database server (2 AMD Cpu + 2Gb memory + 2Gb swap > space) started to suffer from memory outages because of heavy load. > During day available free memory is changing from 200Mb to 5Mb and when > available memory reaches to 5Mb MySQL starts to give 'Too many > connections' messages. Db server is working with 45-70 query/second and > more than 25,712 connection per hour. There are active 10-13 threads > serving databases. > > To increase available free memory I've did the following : > 1- Optimized all tables > 2- Removed unneccessary/old indexes > 3- Moved unused databases to replication server > 4- Increased key_buffer_size from 8Mb to 128Mb > 5- Have increased max_connection from 100 to 150 > 6- Have increased thread_cache to 5 > > This changes helped a bit but still memory is a problem for MySQL. What > should I do to prevent 'too many connections' messages and have more > memory available on database servers? Should I remove more indexes from > tables? Should I increase key_buffer_size to 256Mb or more? > Key_buffer_size doesn't look like a problem since key efficiency looks > 100% most of the time. > > > Thank you for your time > > Kayra Otaner > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
