MySQL reserves too much RAM
- by Buddy
I have a cheap VPS with 128Mb RAM and 256Mb burst. MySQL starts and reserves about 110Mb, but uses not more than 20Mb of them. My VPS Control Panel shows, that I use 127Mb (I also running nginx and sphinx), I know, that it shows reserved RAM, but when I reach over 128Mb, my VPS reboots automatically every 4 hours. So I want to force MySQL to reserve less RAM. How can i do that? I did some tweaks with my.conf but it helped not so much.
top output:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 15 0 2156 668 572 S 0.0 0.3 0:00.03 init
11311 root 15 0 11212 356 228 S 0.0 0.1 0:00.00 vzctl
11312 root 18 0 3712 1484 1248 S 0.0 0.6 0:00.01 bash
11347 root 18 0 2284 916 732 R 0.0 0.3 0:00.00 top
13978 root 17 -4 2248 552 344 S 0.0 0.2 0:00.00 udevd
14262 root 15 0 1812 564 472 S 0.0 0.2 0:00.03 syslogd
14293 sphinx 15 0 11816 1172 672 S 0.0 0.4 0:00.07 searchd
14305 root 25 0 7192 1036 636 S 0.0 0.4 0:00.00 sshd
14321 root 25 0 2832 836 668 S 0.0 0.3 0:00.00 xinetd
15389 root 18 0 3708 1300 1132 S 0.0 0.5 0:00.00 mysqld_safe
15441 mysql 15 0 113m 16m 4440 S 0.0 6.4 0:00.15 mysqld
15489 root 21 0 13056 1456 340 S 0.0 0.6 0:00.00 nginx
15490 nginx 18 0 13328 2388 992 S 0.0 0.9 0:00.06 nginx
15507 nginx 25 0 19520 5888 4244 S 0.0 2.2 0:00.00 php-cgi
15508 nginx 18 0 19636 4876 2748 S 0.0 1.9 0:00.12 php-cgi
15509 nginx 15 0 19668 4872 2716 S 0.0 1.9 0:00.11 php-cgi
15518 root 18 0 4492 1116 568 S 0.0 0.4 0:00.01 crond
MySQL tuner:
>> MySQLTuner 1.0.1 - Major Hayden <[email protected]>
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with '--help' for additional options and output filtering
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password:
-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.0.77
[OK] Operating on 32-bit architecture with less than 2GB RAM
-------- Storage Engine Statistics -------------------------------------------
[--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in InnoDB tables: 1M (Tables: 1)
[OK] Total fragmented tables: 0
-------- Performance Metrics -------------------------------------------------
[--] Up for: 38m 43s (37 q [0.016 qps], 20 conn, TX: 4M, RX: 3K)
[--] Reads / Writes: 100% / 0%
[--] Total buffers: 28.1M global + 832.0K per thread (100 max threads)
[OK] Maximum possible memory usage: 109.4M (42% of installed RAM)
[OK] Slow queries: 0% (0/37)
[OK] Highest usage of available connections: 1% (1/100)
[OK] Key buffer size / total MyISAM indexes: 128.0K/64.0K
[OK] Query cache efficiency: 42.1% (8 cached / 19 selects)
[OK] Query cache prunes per day: 0
[!!] Temporary tables created on disk: 27% (3 on disk / 11 total)
[!!] Thread cache is disabled
[OK] Table cache hit rate: 57% (8 open / 14 opened)
[OK] Open file limit used: 1% (12/1K)
[OK] Table locks acquired immediately: 100% (22 immediate / 22 locks)
[!!] Connections aborted: 10%
[OK] InnoDB data size / buffer pool: 1.5M/8.0M
-------- Recommendations -----------------------------------------------------
General recommendations:
MySQL started within last 24 hours - recommendations may be inaccurate
Enable the slow query log to troubleshoot bad queries
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries without LIMIT clauses
Set thread_cache_size to 4 as a starting value
Your applications are not closing MySQL connections properly
Variables to adjust:
tmp_table_size (> 32M)
max_heap_table_size (> 16M)
thread_cache_size (start at 4)
I think if I do what MySQLtuner says, MySQL will use more RAM.
