Greenplum 6已合并到PostgreSQL 9.3版本 - 比上一代GP提升:8倍读,195倍更新、删除 - 另有大量PG新特性

11 minute read

背景

Greenplum 6已合并到PostgreSQL 9.3版本 - 相比5性能提升:读8倍,更新、删除195倍 - 另有大量PG新特性,详见PostgreSQL release notes

https://www.postgresql.org/docs/11/static/release.html

例如

1、GIN、SPGIST 索引接口。在模糊查询、全文检索、向量相似计算方面终于有索引加速了。

2、异步事务,小事务写入有大幅提升。

3、物化视图,OLAP中很好用的功能。

4、事件触发器,基于事件控制细粒度DDL权限。

5、整体性能增强。

以上特性都是通过升级PostgreSQL版本加入的。

其他增强:

1、增加跨表的分布式死锁检测。

2、更新、删除由表级排他锁改成行级排他锁,大幅提升DML性能。

gpdb 6 部署示例

与如下同测试环境:

《Deepgreen(Greenplum) 多机部署测试 , TPC-H VS citus》

配置ECS虚拟机OS参数 (all host)

1、内核参数

vi /etc/sysctl.conf      
      
# add by digoal.zhou          
fs.aio-max-nr = 1048576          
fs.file-max = 76724600          
          
# 可选:kernel.core_pattern = /data01/corefiles/core_%e_%u_%t_%s.%p                   
# /data01/corefiles 事先建好,权限777,如果是软链接,对应的目录修改为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%),单位为页。          
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,单位为字节。          
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          
#  默认为10%,大内存机器建议调整为直接指定多少字节          
          
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.swappiness = 0          
#  不使用交换分区          
          
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.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          
fs.nr_open=20480000          
# 单个进程允许打开的文件句柄上限          
          
# 以下参数请注意          
# vm.extra_free_kbytes = 4096000          
# vm.min_free_kbytes = 2097152          
# 如果是小内存机器,以上两个值不建议设置          
# vm.nr_hugepages = 66536              
#  建议shared buffer设置超过64GB时 使用大页,页大小 /proc/meminfo Hugepagesize          
# vm.lowmem_reserve_ratio = 1 1 1          
# 对于内存大于64G时,建议设置,否则建议默认值 256 256 32      

2、资源限制

vi /etc/security/limits.conf      
      
# nofile超过1048576的话,一定要先将sysctl的fs.nr_open设置为更大的值,并生效后才能继续设置nofile.          
          
* soft    nofile  1024000          
* hard    nofile  1024000          
* soft    nproc   unlimited          
* hard    nproc   unlimited          
* soft    core    unlimited          
* hard    core    unlimited          
* soft    memlock unlimited          
* hard    memlock unlimited         

3、关闭透明大页,使用精准时钟(可选)

vi /etc/rc.local      
      
touch /var/lock/subsys/local      
           
if test -f /sys/kernel/mm/transparent_hugepage/enabled; then          
   echo never > /sys/kernel/mm/transparent_hugepage/enabled          
fi        
    
# tsc 时钟    
echo tsc > /sys/devices/system/clocksource/clocksource0/current_clocksource      
chmod +x /etc/rc.d/rc.local  

部署gpdb (all host)

1、部署依赖(root执行)

rpm -ivh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm     
  
yum install -y coreutils glib2 lrzsz mpstat dstat sysstat e4fsprogs xfsprogs ntp readline-devel zlib-devel openssl-devel pam-devel libxml2-devel libxslt-devel python-devel tcl-devel gcc make smartmontools flex bison perl-devel perl-ExtUtils* openldap-devel jadetex  openjade bzip2 curl-devel curl apr-devel apr cmake3 python git iotop perf gcc-c++ dstat bzip2-devel krb5-devel libcurl-devel libevent-devel libkadm5 libyaml-devel libxml2-devel openssl-devel perl-ExtUtils-Embed python-devel sysstat python-pip xerces-c-devel  
  
  
  
pip install --upgrade pip  
  
pip install paramiko  pycrypto psutil lockfile pidlockfile  

2、部署gpdb(root执行)

cd ~  
git clone https://github.com/greenplum-db/gpdb  
cd gpdb  
  
pip install -r python-dependencies.txt  
  
pip install -r python-developer-dependencies.txt  
  
  
./configure --disable-orca --with-perl --with-python --with-libxml --prefix=/opt/gpdb6  
make -j 128  
make install  

3、检查当前GPDB的pg版本

/opt/gpdb6/bin/psql -V  
psql (PostgreSQL) 9.3beta1  

规划存储目录 (all host)

useradd digoal  
passwd digoal   
  
  
  
mkdir /data01/gpdb6  
chown digoal:digoal /data01/gpdb6  

初始化GPDB集群 (master host)

1、配置文件

vi /opt/gpdb6/greenplum_path.sh   
  
# 追加  
export MASTER_DATA_DIRECTORY=/data01/gpdb6/gp-1  
export PGDATA=$MASTER_DATA_DIRECTORY  
export PGHOST=127.0.0.1  
export PGPORT=18000  
export PGUSER=digoal  
export PGPASSWORD=123  
export PGDATABASE=postgres  

2、环境变量

su - digoal  
  
  
vi ~/.bash_profile  
  
# 追加  
. /opt/gpdb6/greenplum_path.sh  

3、配置集群主机文件,包含所有节点(master, standby, segment, mirror hosts)

su - digoal  
  
vi hostfile  
  
digoal-citus-gpdb-test001  
digoal-citus-gpdb-test002  
digoal-citus-gpdb-test003  
digoal-citus-gpdb-test004  
digoal-citus-gpdb-test005  
digoal-citus-gpdb-test006  
digoal-citus-gpdb-test007  
digoal-citus-gpdb-test008  
digoal-citus-gpdb-test009  

4、配置host认证

《Deepgreen(Greenplum) 多机部署测试 , TPC-H VS citus》

gpssh-exkeys -f ./hostfile  

5、配置集群初始化文件

如果master host不想配置segment node,则需要修改一下以上hostfile,把master host去掉。

本例在所有主机上初始化segment.

vi cluster.conf  
  
ARRAY_NAME="mpp1 cluster"  
CLUSTER_NAME="mpp1 cluster"  
MACHINE_LIST_FILE=hostfile  
SEG_PREFIX=gp  
DATABASE_PREFIX=gp  
PORT_BASE=28000  
declare -a DATA_DIRECTORY=(/data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6 /data01/gpdb6)  
MASTER_HOSTNAME=digoal-citus-gpdb-test001  
MASTER_DIRECTORY=/data01/gpdb6  
MASTER_PORT=18000  
IP_ALLOW=0.0.0.0/0  
TRUSTED_SHELL=/usr/bin/ssh  
CHECK_POINT_SEGMENTS=32  
ENCODING=UNICODE  
export MASTER_DATA_DIRECTORY  
export TRUSTED_SHELL  
DEFAULT_QD_MAX_CONNECT=250  
QE_CONNECT_FACTOR=5  

6、初始化集群

. /opt/gpdb6/greenplum_path.sh   
  
  
  
gpinitsystem -c cluster.conf -h hostfile   

7、配置参数

gpconfig -c max_connections -v 500 -m 400  
gpconfig -c shared_buffers -v '1GB'  
gpconfig -c max_prepared_transactions -v '1500'  
gpconfig -c max_stack_depth -v '4MB'  
gpconfig -c vacuum_cost_delay -v '0'  
gpconfig -c synchronous_commit -v 'off'  
gpconfig -c wal_buffers -v '16MB'  
gpconfig -c wal_writer_delay -v '10ms'  
gpconfig -c checkpoint_segments -v '128' --skipvalidation  
gpconfig -c random_page_cost -v '1.3'  
gpconfig -c log_statement -v 'ddl'  
gpconfig -c vacuum_freeze_table_age -v '1200000000'  
gpconfig -c autovacuum_freeze_max_age -v '1300000000' --skipvalidation  
gpconfig -c autovacuum_vacuum_cost_delay -v '0' --skipvalidation  
gpconfig -c autovacuum -v 'on' --skipvalidation  

重启实例

gpstop -M fast -a  
  
gpstart -a  

以下参数不允许修改,详见GUC文件

src/backend/utils/misc/guc.c

autovacuum  
autovacuum_freeze_max_age  
autovacuum_vacuum_cost_delay  

GPDB 6 改进评测

1 支持异步事务

PostgreSQL 8.3 就有了,异步事务开启后,对于IO性能较差的盘,小事务的性能提升非常明显。

synchronous_commit = off  
wal_buffers = 16MB  
wal_writer_delay = 10ms  

2 gin 倒排索引

GIN倒排索引,支持多值列(例如数组、JSON、HSTORE、全文检索),多列任意组合查询索引加速。

例子

postgres=# create table t(id int, c1 int[]);  
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.  
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.  
CREATE TABLE  
  
postgres=# create index idx_t_1 on t using gin (c1);  
CREATE INDEX  
  
postgres=# create or replace function gen_rand_arr(int,int) returns int[] as $$  
postgres$#   select array(select (random()*$1)::int from generate_series(1,$2));  
postgres$# $$ language sql strict;  
CREATE FUNCTION  
  
  
postgres=# select gen_rand_arr(100,10);  
         gen_rand_arr            
-------------------------------  
 {3,85,71,73,91,2,29,81,69,77}  
(1 row)  
  
postgres=# insert into t select id,gen_rand_arr(10000,10) from generate_series(1,10000000) t(id);  
INSERT 0 10000000  
  
  
postgres=# explain analyze select * from t where c1 @> array[1,2];  
                                                      QUERY PLAN                                                         
-----------------------------------------------------------------------------------------------------------------------  
 Gather Motion 4:1  (slice1; segments: 4)  (cost=6.50..7.81 rows=1 width=65) (actual time=0.340..0.426 rows=5 loops=2)  
   ->  Bitmap Heap Scan on t  (cost=6.50..7.81 rows=1 width=65) (actual time=0.329..0.335 rows=2 loops=2)  
         Recheck Cond: (c1 @> '{1,2}'::integer[])  
         ->  Bitmap Index Scan on idx_t_1  (cost=0.00..6.50 rows=1 width=0) (actual time=0.259..0.259 rows=0 loops=2)  
               Index Cond: (c1 @> '{1,2}'::integer[])  
   (slice0)    Executor memory: 322K bytes.  
   (slice1)    Executor memory: 779K bytes avg x 4 workers, 907K bytes max (seg1).  Work_mem: 33K bytes max.  
 Memory used:  128000kB  
 Optimizer: legacy query optimizer  
 Total runtime: 1.208 ms  
(10 rows)  
  
set enable_bitmapscan =off;  
  
postgres=# explain analyze select * from t where c1 @> array[1,2];  
                                                         QUERY PLAN                                                           
----------------------------------------------------------------------------------------------------------------------------  
 Gather Motion 4:1  (slice1; segments: 4)  (cost=0.00..16.50 rows=1 width=65) (actual time=503.962..636.780 rows=5 loops=2)  
   ->  Seq Scan on t  (cost=0.00..16.50 rows=1 width=65) (actual time=34.927..588.086 rows=2 loops=2)  
         Filter: (c1 @> '{1,2}'::integer[])  
   (slice0)    Executor memory: 322K bytes.  
   (slice1)    Executor memory: 54K bytes avg x 4 workers, 54K bytes max (seg0).  
 Memory used:  128000kB  
 Optimizer: legacy query optimizer  
 Total runtime: 1273.949 ms  
(8 rows)  

相比全表扫描,使用GIN索引的查询性能提升上千倍。

3 spgist 索引,范围类型

spgist索引接口,以及范围类型。

postgres=# create table t(id int, rg int4range);  
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.  
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.  
CREATE TABLE  
postgres=# create index idx_t_1 on t using spgist (rg);  
CREATE INDEX  
postgres=# insert into t values (1, int4range(1,100));  
INSERT 0 1  
postgres=# insert into t values (2, int4range(101,200));  
INSERT 0 1  
  
postgres=# explain select * from t where rg @> 1;  
                                 QUERY PLAN                                    
-----------------------------------------------------------------------------  
 Gather Motion 4:1  (slice1; segments: 4)  (cost=0.12..2.74 rows=1 width=18)  
   ->  Index Scan using idx_t_1 on t  (cost=0.12..2.74 rows=1 width=18)  
         Index Cond: (rg @> 1)  
 Optimizer: legacy query optimizer  
(4 rows)  
  
postgres=# select * from t where rg @> 1;  
 id |   rg      
----+---------  
  1 | [1,100)  
(1 row)  

范围类型在一些场景的应用

《会议室预定系统实践(解放开发) - PostgreSQL tsrange(时间范围类型) + 排他约束》

《PostgreSQL 黑科技 range 类型及 gist index 20x+ speedup than Mysql index combine query》

4 增加行级排他锁,优化分布式死锁检测

1、原有分布式死锁检测

postgres=# show deadlock_timeout ;  
 deadlock_timeout   
------------------  
 1s  
(1 row)  
  
  
postgres=# create table a (id int, c1 int);  
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.  
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.  
CREATE TABLE  
Time: 156.785 ms  
postgres=# create table b (id int, c1 int);  
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.  
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.  
CREATE TABLE  
Time: 87.583 ms  
  
  
postgres=# insert into a values (1,1);  
INSERT 0 1  
Time: 58.180 ms  
postgres=# insert into b values (1,1);  
INSERT 0 1  
Time: 72.548 ms  
  
  
postgres=# begin;  
BEGIN  
postgres=# update b set c1=2 where id=1;  
UPDATE 1  
...  
postgres=# update a set c1=2 where id=1;  
UPDATE 1  
  
  
postgres=# begin;  
BEGIN  
Time: 1.997 ms  
postgres=# update a set c1=2 where id=1;  
UPDATE 1  
Time: 1.425 ms  
...  
postgres=# update b set c1=2 where id=1;  
ERROR:  deadlock detected  
LINE 1: update b set c1=2 where id=1;  
               ^  
DETAIL:  Process 26021 waits for ExclusiveLock on relation 36930 of database 12097; blocked by process 26091.  
Process 26091 waits for ExclusiveLock on relation 36927 of database 12097; blocked by process 26021.  

gpdb 6 与 gpdb 5 行为一致

postgres=# begin;  
BEGIN  
postgres=# update a set c1=2 where id=1;  
UPDATE 1  
...  
postgres=# update b set c1=2 where id=1;  
UPDATE 1  
  
  
postgres=# begin;  
BEGIN  
postgres=# update b set c1=3 where id=1;  
UPDATE 1  
...  
postgres=# update a set c1=3 where id=1;  
ERROR:  deadlock detected  (seg2 127.0.0.1:24002 pid=3721)  
DETAIL:  Process 3721 waits for ShareLock on transaction 1306618; blocked by process 3703.  
Process 3703 waits for ShareLock on transaction 1306619; blocked by process 3721.  
HINT:  See server log for query details.  

2、gpdb6增加了行级锁

(gpdb6以前为表级排他锁)

对同一张表的delete\update操作,堵塞insert\update\delete

begin;  
update a set c1=2 where id=1;  

堵塞其他会话对同一张表的如下操作:insert\update\delete:

update a set c1=3 where id=2;  
insert into a values (3,1);  
delete from a where id=2;  

gpdb6

行级锁,以上操作不堵塞。

行级分布式死锁检测,参数gp_global_deadlock_detector_period

postgres=# show gp_global_deadlock_detector_period;  
 gp_global_deadlock_detector_period   
------------------------------------  
 2min  
(1 row)  
  
  
  
postgres=# create table a (id int, c1 int);  
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.  
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.  
CREATE TABLE  
postgres=# insert into a values (1,1),(2,2);  
INSERT 0 2  
postgres=# begin;  
BEGIN  
postgres=# update a set c1=2 where id=1;  
UPDATE 1  
...  
postgres=# update a set c1=1 where id=2;  
UPDATE 1  
  
  
postgres=# begin;  
BEGIN  
postgres=# update a set c1=3 where id=2;  
UPDATE 1  
...  
postgres=# update a set c1=3 where id=1;  
ERROR:  canceling statement due to user request: "cancelled by global deadlock detector"  

5 TP性能提升

1亿数据量,TPCB,只读,读写混合测试。

pgbench -i -s 1000 -h 127.0.0.1 -p 15432 -U postgres postgres  
  
pgbench -M simple -v -r -P 1 -c 16 -j 16 -h 127.0.0.1 -p 15432 -U postgres postgres -T 120 -S  
  
pgbench -M simple -v -r -P 1 -c 16 -j 16 -h 127.0.0.1 -p 15432 -U postgres postgres -T 120  

1 gpdb 5

postgres=# select version();  
                        version               
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------  
 PostgreSQL 8.3.23 (Greenplum Database 5.10.2+7615c3b build ga) on x86_64-pc-linux-gnu, compiled by GCC gcc (GCC) 6.3.1 20170216 (Red Hat 6.3.1-3), 64-bit compiled on Aug 25 2018 08:21:26  
(1 row)  
  
postgres=# show gp_server_version;  
    gp_server_version      
-------------------------  
 5.10.2+7615c3b build ga  
(1 row)  
  
postgres=# show gp_server_version_num;  
 gp_server_version_num   
-----------------------  
 51002  
(1 row)  

1、tpcb 只读

transaction type: <builtin: select only>  
scaling factor: 1000  
query mode: simple  
number of clients: 16  
number of threads: 16  
duration: 120 s  
number of transactions actually processed: 361911  
latency average = 5.306 ms  
latency stddev = 0.854 ms  
tps = 3014.205774 (including connections establishing)  
tps = 3014.474824 (excluding connections establishing)  
script statistics:  
 - statement latencies in milliseconds:  
         0.002  \set aid random(1, 100000 * :scale)  
         5.303  SELECT abalance FROM pgbench_accounts WHERE aid = :aid;  

2、tpcb 读写混合

transaction type: <builtin: TPC-B (sort of)>  
scaling factor: 1000  
query mode: simple  
number of clients: 16  
number of threads: 16  
duration: 120 s  
number of transactions actually processed: 1822  
latency average = 1057.754 ms  
latency stddev = 130.580 ms  
tps = 15.074113 (including connections establishing)  
tps = 15.075498 (excluding connections establishing)  
script statistics:  
 - statement latencies in milliseconds:  
         0.005  \set aid random(1, 100000 * :scale)  
         0.001  \set bid random(1, 1 * :scale)  
         0.001  \set tid random(1, 10 * :scale)  
         0.001  \set delta random(-5000, 5000)  
         2.417  BEGIN;  
       990.377  UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;  
         7.147  SELECT abalance FROM pgbench_accounts WHERE aid = :aid;  
         1.186  UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;  
         1.081  UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;  
         0.674  INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);  
        54.865  END;  

2 gpdb 6

psql  
psql (9.3beta1)  
Type "help" for help.  
  
postgres=# select version();  
                                   version                
---------------------------------------------------------------------------------------------------------------------------------------------------------  
 PostgreSQL 9.3beta1 (Greenplum Database 6.0.0-alpha.0+dev.11201.gb2e98d4 build dev-oss) on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28), 64-bit compiled on Sep 26 2018 15:00:09  
(1 row)  
  
postgres=# show gp_server_version;  
               gp_server_version                  
------------------------------------------------  
 6.0.0-alpha.0+dev.11201.gb2e98d4 build dev-oss  
(1 row)  
  
postgres=# show gp_server_version_num;  
 gp_server_version_num   
-----------------------  
 60000  
(1 row)  

1、tpcb 只读

transaction type: <builtin: select only>  
scaling factor: 1000  
query mode: simple  
number of clients: 16  
number of threads: 16  
duration: 120 s  
number of transactions actually processed: 3006326  
latency average = 0.639 ms  
latency stddev = 0.107 ms  
tps = 25052.487094 (including connections establishing)  
tps = 25056.694155 (excluding connections establishing)  
script statistics:  
 - statement latencies in milliseconds:  
         0.002  \set aid random(1, 100000 * :scale)  
         0.637  SELECT abalance FROM pgbench_accounts WHERE aid = :aid;  

2、tpcb 读写混合

transaction type: <builtin: TPC-B (sort of)>  
scaling factor: 1000  
query mode: simple  
number of clients: 16  
number of threads: 16  
duration: 120 s  
number of transactions actually processed: 351382  
latency average = 5.465 ms  
latency stddev = 9.487 ms  
tps = 2927.029739 (including connections establishing)  
tps = 2927.497105 (excluding connections establishing)  
script statistics:  
 - statement latencies in milliseconds:  
         0.002  \set aid random(1, 100000 * :scale)  
         0.001  \set bid random(1, 1 * :scale)  
         0.001  \set tid random(1, 10 * :scale)  
         0.000  \set delta random(-5000, 5000)  
         0.195  BEGIN;  
         0.779  UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;  
         0.692  SELECT abalance FROM pgbench_accounts WHERE aid = :aid;  
         0.703  UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;  
         0.685  UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;  
         0.566  INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);  
         1.838  END;  

小结

Greenplum 6已合并到PostgreSQL 9.3版本,相比5性能提升:读8倍,更新、删除195倍,同时有大量PG新特性,例如

1、GIN、SPGIST 索引接口。在模糊查询、全文检索、向量相似计算方面支持索引加速。 1000万行的数组检索,性能提升了1000倍。

2、支持异步事务,小事务写入有大幅提升。

3、支持物化视图,OLAP中很好用的功能。

4、事件触发器,基于事件控制细粒度DDL权限。

5、整体性能增强,OLTP 读8倍,更新、删除195倍。

以上特性都是通过升级PostgreSQL版本加入的。

其他增强:

1、增加跨表的分布式死锁检测。

2、更新、删除由表级排他锁改成行级排他锁,大幅提升DML性能。表现在OLTP方面,更新、删除混合测试TPCB 提升了195倍。

参考

https://www.postgresql.org/docs/11/static/release.html

https://github.com/greenplum-db/gpdb

《Deepgreen(Greenplum) 多机部署测试 , TPC-H VS citus》

《会议室预定系统实践(解放开发) - PostgreSQL tsrange(时间范围类型) + 排他约束》

《PostgreSQL 黑科技 range 类型及 gist index 20x+ speedup than Mysql index combine query》

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