Dan, Heikki, ----- Original Message ----- From: "Heikki Tuuri" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, February 07, 2004 11:39 AM Subject: Re: Memory Leak using InnoDB ?
> Geoffrey, Dan, > > ----- Original Message ----- > From: "Dan Nelson" <[EMAIL PROTECTED]> > Newsgroups: mailing.database.myodbc > Sent: Saturday, February 07, 2004 5:27 AM > Subject: Re: Memory Leak using InnoDB ? > > > > In the last episode (Feb 07), Geoffrey said: > > > I'm running MySQL 4.0.17 with RH Linux 8 on Xeon 3.0/1GB RAM. > > > > > > One application has to access the database (1 connection to the DB is > > > open on startup and left open). However this application performs a > > > lot of queries on the DB. > > > > > > Thanks to "top", I can see that the "used memory" is constantly > > > increasing and never freed (up to 1 GB) when performing a lot of > > > queries. In fact, I can see the total memory usage increasing but the > > > mysqld process memory usage remains the same. > > > > > > When the DB is not accessed, the memory usage is stable. Stopping MySQL > > > server doesn't free the abnormaly allocated memory. > > > > Ideally, you should have very little "free" memory according to top > > (most systems will see under 20MB free). Free memory is wasted memory. > > Unix uses memory not allocated to processes for a disk cache. To > > determine whether you are truly low on memory, run iostat and watch the > > swap columns. Constant swap activity means you're low on memory. > > Dan is right. A memory leak in the mysqld process should show up in the > 'top' line for that process. > > By the way, monitoring if InnoDB has memory leaks is very easy. Just look > with SHOW INNODB STATUS at the 'total allocated memory'. If that keeps > climbing without bounds, that is an indication of a memory leak. > Thanks for your help. For testing, I tried the following my.cnf : server-id=1 socket=/tmp/mysql.sock innodb_data_file_path = ibdata1:750M:autoextend set-variable = innodb_buffer_pool_size=50M set-variable = innodb_additional_mem_pool_size=10M set-variable = innodb_log_file_size=300M set-variable = innodb_log_buffer_size=2M innodb_flush_log_at_trx_commit=0 skip-locking set-variable = max_connections=5 set-variable = read_buffer_size=1M set-variable = sort_buffer=1M set-variable = key_buffer=10M Here is the result of "top" after 20 hours : 8:26pm up 18:35, 1 user, load average: 0.42, 0.26, 0.20 46 processes: 44 sleeping, 2 running, 0 zombie, 0 stopped CPU states: 3.7% user, 0.5% system, 0.0% nice, 95.6% idle Mem: 1031048K av, 1021460K used, 9588K free, 0K shrd, 55288K buff Swap: 2044072K av, 0K used, 2044072K free 845544K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 960 mysql 15 0 67872 66M 2656 S 0.1 6.5 6:29 mysqld Here is the result of "top" after a reboot : 8:54pm up 9 min, 1 user, load average: 0.16, 0.17, 0.10 46 processes: 44 sleeping, 2 running, 0 zombie, 0 stopped CPU states: 4.5% user, 0.3% system, 0.0% nice, 95.0% idle Mem: 1031048K av, 136512K used, 894536K free, 0K shrd, 13276K buff Swap: 2044072K av, 0K used, 2044072K free 61620K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 774 mysql 15 0 36276 35M 2496 S 0.7 3.5 0:03 mysqld Here is the SHOW INNODB STATUS after 20 hours : ---------------------- BUFFER POOL AND MEMORY ---------------------- Total memory allocated 75115912; in additional pool allocated 1611008 Buffer pool size 3200 Free buffers 1 Database pages 3091 Modified db pages 160 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages read 7212, created 2274, written 801221 0.00 reads/s, 0.02 creates/s, 12.45 writes/s Buffer pool hit rate 1000 / 1000 As far as I understand, the "Total Mem" increasing constantly when MySQL is heavily accessed is not really memory allocated by MySQL but allocated by Linux to take advantage of the unused memory ? So I should not pay attention to it (as long as used swap is 0). Correct ? Regards. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
