[MySql] mysql 사용 메모리 줄이기

mysql memory usage and process count reduce

쓰레드 기본 27개

프로세서의 메모리 사용량 보기
ps aux | grep mysql  

ps -eLf  | grep mysql  //쓰레드 수 보기

- 메모리 감시
watch "ps axuw| grep mysql"


//==================
리눅스

     - 설정파일 읽는 순서 알아내기 명령

> mysqladmin --help | grep -A1 'Default options'

Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf

 

or /etc/mysql/mysql.cnf 파일에 옵션이 없으면 직접 추가

 

윈도우 

C:\ProgramData\MySQL\MySQL Server 5.7\my.ini


[mysqld]

performance_schema = off
show_compatibility_56 = 1

innodb_buffer_pool_size = 100M #기본 134M

max_connections = 10 # 기본 150
max_user_connections = 5 # 0
# max_delayed_threads = 1

# thread_cache_size=1

# key_buffer              = 8M        #에러 발생
query_cache_size        = 8M     # v8이상에서는 미지원
query_cache_limit       = 512K
thread_stack            = 128K

 

//====
performance_schema 설정은 처음 시작에선 효과가 있지만 사용을 시작하면 별 효과 없음

//======
- 재시작
systemctl restart mysql

//==================================
- mysql 메모리 보기 스크립트
https://tech.labelleassiette.com/how-to-reduce-the-memory-usage-of-mysql-61ea7d1a9bd
#!/bin/sh
# you might want to add some user authentication here
mysql -u 사용자ID -p  -e "show variables; show status" | awk '
{
VAR[$1]=$2
}
END {
MAX_CONN = VAR["max_connections"]
MAX_USED_CONN = VAR["Max_used_connections"]
BASE_MEM=VAR["key_buffer_size"] + VAR["query_cache_size"] + VAR["innodb_buffer_pool_size"] + VAR["innodb_additional_mem_pool_size"] + VAR["innodb_log_buffer_size"]
MEM_PER_CONN=VAR["read_buffer_size"] + VAR["read_rnd_buffer_size"] + VAR["sort_buffer_size"] + VAR["join_buffer_size"] + VAR["binlog_cache_size"] + VAR["thread_stack"] + VAR["tmp_table_size"]
MEM_TOTAL_MIN=BASE_MEM + MEM_PER_CONN*MAX_USED_CONN
MEM_TOTAL_MAX=BASE_MEM + MEM_PER_CONN*MAX_CONNprintf "+------------------------------------------+--------------------+\n"
printf "| %40s | %15.3f MB |\n", "key_buffer_size", VAR["key_buffer_size"]/1048576
printf "| %40s | %15.3f MB |\n", "query_cache_size", VAR["query_cache_size"]/1048576
printf "| %40s | %15.3f MB |\n", "innodb_buffer_pool_size", VAR["innodb_buffer_pool_size"]/1048576
printf "| %40s | %15.3f MB |\n", "innodb_additional_mem_pool_size", VAR["innodb_additional_mem_pool_size"]/1048576
printf "| %40s | %15.3f MB |\n", "innodb_log_buffer_size", VAR["innodb_log_buffer_size"]/1048576
printf "+------------------------------------------+--------------------+\n"
printf "| %40s | %15.3f MB |\n", "BASE MEMORY", BASE_MEM/1048576
printf "+------------------------------------------+--------------------+\n"
printf "| %40s | %15.3f MB |\n", "sort_buffer_size", VAR["sort_buffer_size"]/1048576
printf "| %40s | %15.3f MB |\n", "read_buffer_size", VAR["read_buffer_size"]/1048576
printf "| %40s | %15.3f MB |\n", "read_rnd_buffer_size", VAR["read_rnd_buffer_size"]/1048576
printf "| %40s | %15.3f MB |\n", "join_buffer_size", VAR["join_buffer_size"]/1048576
printf "| %40s | %15.3f MB |\n", "thread_stack", VAR["thread_stack"]/1048576
printf "| %40s | %15.3f MB |\n", "binlog_cache_size", VAR["binlog_cache_size"]/1048576
printf "| %40s | %15.3f MB |\n", "tmp_table_size", VAR["tmp_table_size"]/1048576
printf "+------------------------------------------+--------------------+\n"
printf "| %40s | %15.3f MB |\n", "MEMORY PER CONNECTION", MEM_PER_CONN/1048576
printf "+------------------------------------------+--------------------+\n"
printf "| %40s | %18d |\n", "Max_used_connections", MAX_USED_CONN
printf "| %40s | %18d |\n", "max_connections", MAX_CONN
printf "+------------------------------------------+--------------------+\n"
printf "| %40s | %15.3f MB |\n", "TOTAL (MIN)", MEM_TOTAL_MIN/1048576
printf "| %40s | %15.3f MB |\n", "TOTAL (MAX)", MEM_TOTAL_MAX/1048576
printf "+------------------------------------------+--------------------+\n"
}'

 

//=======================================

실행 결과
|                          key_buffer_size |          16.000 MB |
|                         query_cache_size |          16.000 MB |
|                  innodb_buffer_pool_size |         100.000 MB |
|          innodb_additional_mem_pool_size |           0.000 MB |
|                   innodb_log_buffer_size |          16.000 MB |
+------------------------------------------+--------------------+
|                              BASE MEMORY |         148.000 MB |
+------------------------------------------+--------------------+
|                         sort_buffer_size |           0.250 MB |
|                         read_buffer_size |           0.125 MB |
|                     read_rnd_buffer_size |           0.250 MB |
|                         join_buffer_size |           0.250 MB |
|                             thread_stack |           0.188 MB |
|                        binlog_cache_size |           0.031 MB |
|                           tmp_table_size |          16.000 MB |
+------------------------------------------+--------------------+
|                    MEMORY PER CONNECTION |          17.094 MB |
+------------------------------------------+--------------------+
|                     Max_used_connections |                  1 |
|                          max_connections |                 30 |
+------------------------------------------+--------------------+
|                              TOTAL (MIN) |         165.094 MB |
|                              TOTAL (MAX) |         148.000 MB |
+------------------------------------------+--------------------+

//==================================

// 참고
- mysql 설정 보기
show global variables like "%connection%";
show global status like '%thread%';
show global variables like '%thread%';

- 에러 보기
systemctl status mysql.service
journalctl -xe