PostgreSQL 系统参数调整及并行设置（转）

转自：https://yq.aliyun.com/teams/5

OS 准备

# yum -y install coreutils glib2 lrzsz sysstat e4fsprogs xfsprogs ntp readline-devel zlib zlib-devel openssl openssl-devel pam-devel libxml2-devel libxslt-devel python-devel tcl-devel gcc make smartmontools flex bison perl perl-devel perl-ExtUtils* openldap openldap-devel

# vi /etc/sysctl.conf
# add by digoal.zhou
fs.aio-max-nr = 1048576
fs.file-max = 76724600
kernel.core_pattern= /data01/corefiles/core_%e_%u_%t_%s.%p
# /data01/corefiles事先建好，权限777
kernel.sem = 4096 2147483647 2147483646 512000
# 信号量, ipcs -l 或 -u 查看，每16个进程一组，每组信号量需要17个信号量。
kernel.shmall = 107374182
# 所有共享内存段相加大小限制(建议内存的80%)
kernel.shmmax = 274877906944
# 最大单个共享内存段大小(建议为内存一半), >9.2的版本已大幅降低共享内存的使用
kernel.shmmni = 819200
# 一共能生成多少共享内存段，每个PG数据库集群至少2个共享内存段
net.core.netdev_max_backlog = 10000
net.core.rmem_default = 262144
# The default setting of the socket receive buffer in bytes.
net.core.rmem_max = 4194304
# The maximum receive socket buffer size in bytes
net.core.wmem_default = 262144
# The default setting (in bytes) of the socket send buffer.
net.core.wmem_max = 4194304
# The maximum send socket buffer size in bytes.
net.core.somaxconn = 4096
net.ipv4.tcp_max_syn_backlog = 4096
net.ipv4.tcp_keepalive_intvl = 20
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_time = 60
net.ipv4.tcp_mem = 8388608 12582912 16777216
net.ipv4.tcp_fin_timeout = 5
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syncookies = 1
# 开启SYN Cookies。当出现SYN等待队列溢出时，启用cookie来处理，可防范少量的SYN攻击
net.ipv4.tcp_timestamps = 1
# 减少time_wait
net.ipv4.tcp_tw_recycle = 0
# 如果=1则开启TCP连接中TIME-WAIT套接字的快速回收，但是NAT环境可能导致连接失败，建议服务端关闭它
net.ipv4.tcp_tw_reuse = 1
# 开启重用。允许将TIME-WAIT套接字重新用于新的TCP连接
net.ipv4.tcp_max_tw_buckets = 262144
net.ipv4.tcp_rmem = 8192 87380 16777216
net.ipv4.tcp_wmem = 8192 65536 16777216
net.nf_conntrack_max = 1200000
net.netfilter.nf_conntrack_max = 1200000
vm.dirty_background_bytes = 409600000
#  系统脏页到达这个值，系统后台刷脏页调度进程 pdflush（或其他） 自动将(dirty_expire_centisecs/100）秒前的脏页刷到磁盘
vm.dirty_expire_centisecs = 3000
#  比这个值老的脏页，将被刷到磁盘。3000表示30秒。
vm.dirty_ratio = 95
#  如果系统进程刷脏页太慢，使得系统脏页超过内存 95 % 时，则用户进程如果有写磁盘的操作（如fsync, fdatasync等调用），则需要主动把系统脏页刷出。
#  有效防止用户进程刷脏页，在单机多实例，并且使用CGROUP限制单实例IOPS的情况下非常有效。
vm.dirty_writeback_centisecs = 100
#  pdflush（或其他）后台刷脏页进程的唤醒间隔， 100表示1秒。
vm.extra_free_kbytes = 4096000
vm.min_free_kbytes = 2097152
vm.mmap_min_addr = 65536
vm.overcommit_memory = 0
#  在分配内存时，允许少量over malloc, 如果设置为 1, 则认为总是有足够的内存，内存较少的测试环境可以使用 1 .
vm.overcommit_ratio = 90
#  当overcommit_memory = 2 时，用于参与计算允许指派的内存大小。
vm.swappiness = 0
#  关闭交换分区
vm.zone_reclaim_mode = 0
# 禁用 numa, 或者在vmlinux中禁止.
net.ipv4.ip_local_port_range = 40000 65535
# 本地自动分配的TCP, UDP端口号范围
#  vm.nr_hugepages = 102352
#  建议shared buffer设置超过64GB时 使用大页，页大小 /proc/meminfo Hugepagesize

# sysctl -p

# vi /etc/security/limits.conf
* soft    nofile  1024000
* hard    nofile  1024000
* soft    nproc   unlimited
* hard    nproc   unlimited
* soft    core    unlimited
* hard    core    unlimited
* soft    memlock unlimited
* hard    memlock unlimited

# rm -f /etc/security/limits.d/*

安装

$ wget https://ftp.postgresql.org/pub/source/v9.6.0/postgresql-9.6.0.tar.bz2

$ tar -jxvf postgresql-9.6.0.tar.bz2

$ cd postgresql-9.6.0

$ ./configure --prefix=/home/digoal/pgsql9.6.0

$ make world -j 32
$ make install-world -j 32

$ vi ~/.bash_profile
export PS1="$USER@`/bin/hostname -s`-> "
export PGPORT=5281
export PGDATA=/u02/digoal/pg_root$PGPORT
export LANG=en_US.utf8
export PGHOME=/home/digoal/pgsql9.6.0
export LD_LIBRARY_PATH=$PGHOME/lib:/lib64:/usr/lib64:/usr/local/lib64:/lib:/usr/lib:/usr/local/lib:$LD_LIBRARY_PATH
export DATE=`date +"%Y%m%d%H%M"`
export PATH=$PGHOME/bin:$PATH:.
export MANPATH=$PGHOME/share/man:$MANPATH
export PGHOST=$PGDATA
export PGUSER=postgres
export PGDATABASE=postgres
alias rm='rm -i'
alias ll='ls -lh'
unalias vi

$ . ~/.bash_profile 

$ df -h
/dev/mapper/vgdata01-lv03
                      4.0T  1.3T  2.8T  32% /u01
/dev/mapper/vgdata01-lv04
                      7.7T  899G  6.8T  12% /u02

初始化集群

$ initdb -D $PGDATA -E UTF8 --locale=C -U postgres -X /u01/digoal/pg_xlog$PGPORT

配置数据库参数

$ cd $PGDATA

$ vi postgresql.conf
listen_addresses = '0.0.0.0'
port = 5281
max_connections = 800
superuser_reserved_connections = 13
unix_socket_directories = '.'
unix_socket_permissions = 0700
tcp_keepalives_idle = 60
tcp_keepalives_interval = 10
tcp_keepalives_count = 10
shared_buffers = 128GB
huge_pages = try
maintenance_work_mem = 2GB
dynamic_shared_memory_type = sysv
vacuum_cost_delay = 0
bgwriter_delay = 10ms
bgwriter_lru_maxpages = 1000
bgwriter_lru_multiplier = 10.0
bgwriter_flush_after = 256
max_worker_processes = 128
max_parallel_workers_per_gather = 16
old_snapshot_threshold = 8h
backend_flush_after = 256
synchronous_commit = off
full_page_writes = off
wal_buffers = 128MB
wal_writer_delay = 10ms
wal_writer_flush_after = 4MB
checkpoint_timeout = 55min
max_wal_size = 256GB
checkpoint_flush_after = 1MB
random_page_cost = 1.0
effective_cache_size = 512GB
constraint_exclusion = on
log_destination = 'csvlog'
logging_collector = on
log_checkpoints = on
log_connections = on
log_disconnections = on
log_error_verbosity = verbose
log_timezone = 'PRC'
autovacuum = on
log_autovacuum_min_duration = 0
autovacuum_max_workers = 8
autovacuum_naptime = 10s
autovacuum_vacuum_scale_factor = 0.02
autovacuum_analyze_scale_factor = 0.01
statement_timeout = 0
lock_timeout = 0
idle_in_transaction_session_timeout = 0
gin_fuzzy_search_limit = 0
gin_pending_list_limit = 4MB
datestyle = 'iso, mdy'
timezone = 'PRC'
lc_messages = 'C'
lc_monetary = 'C'
lc_numeric = 'C'
lc_time = 'C'
default_text_search_config = 'pg_catalog.english'
deadlock_timeout = 1s

$ vi pg_hba.conf
local   all             all                                     trust
host    all             all             127.0.0.1/32            trust
host    all             all             ::1/128                 trust
host all all 0.0.0.0/0 md5

启动数据库

$ pg_ctl start

二、多核并行计算相关参数与用法

1. 控制整个数据库集群同时能开启多少个work process，必须设置。

max_worker_processes = 128              # (change requires restart)

2. 控制一个并行的EXEC NODE最多能开启多少个并行处理单元，同时还需要参考表级参数parallel_workers，或者PG内核内置的算法，根据表的大小计算需要开启多少和并行处理单元。  
实际取小的。

max_parallel_workers_per_gather = 16    # taken from max_worker_processes

3. 计算并行处理的成本，如果成本高于非并行，则不会开启并行处理。

#parallel_tuple_cost = 0.1              # same scale as above
#parallel_setup_cost = 1000.0   # same scale as above

4. 小于这个值的表，不会开启并行。

#min_parallel_relation_size = 8MB

5. 告诉优化器，强制开启并行。

#force_parallel_mode = off

6. 表级参数，不通过表的大小计算并行度，而是直接告诉优化器这个表需要开启多少个并行计算单元。

parallel_workers (integer)

This sets the number of workers that should be used to assist a parallel scan of this table.
If not set, the system will determine a value based on the relation size.
The actual number of workers chosen by the planner may be less, for example due to the setting of max_worker_processes.