root@ubuntu160:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Codename: trusty

# 总核数 = 物理CPU个数 X 每颗物理CPU的核数 
# 总逻辑CPU数 = 物理CPU个数 X 每颗物理CPU的核数 X 超线程数
 
# 查看物理CPU个数
cat /proc/cpuinfo| grep "physical id"| sort| uniq| wc -l
# 查看每个物理CPU中core的个数(即核数)
cat /proc/cpuinfo| grep "cpu cores"| uniq
 
# 查看逻辑CPU的个数
cat /proc/cpuinfo| grep "processor"| wc -l

cat /proc/meminfo

--查看所有数据库参数的值
show all； 

ALTER SYSTEM SET configuration_parameter { TO | = } { value | 'value' | DEFAULT }

--参数
show all;
 
show maintenance_work_mem;
--注意这里的设置不会改变postgresql.conf,只会改变postgresql.conf
ALTER SYSTEM SET maintenance_work_mem= 1048576;
 
--重启数据库
show maintenance_work_mem; 
 
--取消postgresql.auto.conf的参数设置
ALTER SYSTEM SET maintenance_work_mem= default;

cd /home/postgres/pgsql/data
cat postgresql.conf

superuser_reserved_connections = 3
unix_socket_directory = '/var/lib/pgsql/current/data/unix_socket'
unix_socket_permissions = 0700
log_min_duration_statement = 10000ms
 
deadlock_timeout = 5s
track_activity_query_size = 10000
stats_temp_directory = 'pg_stat_tmp'
 
autovacuum = on
log_autovacuum_min_duration = 0
shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.max = 10000
pg_stat_statements.track = all
 
track_activities = on
track_counts = on
track_io_timing = on 
 
#log parameter
log_destination = 'csvlog'
logging_collector = on
log_directory = 'pg_log'
log_truncate_on_rotation = on
log_rotation_age = 1d
log_rotation_size = 10MB
log_checkpoints = on
log_lock_waits = on
 
#性能参数调整
 
shared_buffers = 16384MB 
temp_buffers = 1024MB 
work_mem = 2048MB 
maintenance_work_mem = 4096MB