PG数据库提供了一款轻量级的压力测试工具叫pgbench,其实就是一个编译好后的扩展性的可执行文件。介绍如下。
 环境：
CentOS 5.7(final)
PG:9.1.2
Vmware 8.0
数据库参数： max_connection=100 ,其他略，默认

1.安装
进入源码安装包,编译,安装

[postgres@localhost  ~]$ cd postgresql-9.1.2/contrib/pgbench/  [postgres@localhost  pgbench]$ ll  total 164  -rw-r--r--. 1 postgres postgres   538 Dec  1  2011 Makefile  -rwxrwxr-x. 1 postgres postgres 50203 Apr 26 23:50 pgbench  -rw-r--r--. 1 postgres postgres 61154 Dec  1  2011 pgbench.c  -rw-rw-r--. 1 postgres postgres 47920 Apr 26 23:50 pgbench.o  [postgres@localhost  pgbench]$make all  [postgres@localhost  pgbench]$make install

安装完毕以后可以在bin文件夹下看到新生成的pgbench文件

[postgres@localhost  bin]$ ll $PGHOME/bin pgbench  -rwxr-xr-x. 1 postgres postgres 50203 Jul  8 20:28 pgbench

2.参数介绍

[postgres@localhost  bin]$ pgbench --help  pgbench is a benchmarking tool for PostgreSQL.    Usage:    pgbench [OPTIONS]... [DBNAME]    Initialization options:    -i           invokes initialization mode    -F NUM       fill factor    -s NUM       scaling factor    Benchmarking options:    -c NUM       number of concurrent database clients (default: 1)    -C           establish new connection for each transaction    -D VARNAME=VALUE                 define variable for use by custom script    -f FILENAME  read transaction script from FILENAME    -j NUM       number of threads (default: 1)    -l           write transaction times to log file    -M {simple|extended|prepared}                 protocol for submitting queries to server (default: simple)    -n           do not run VACUUM before tests    -N           do not update tables "pgbench_tellers" and "pgbench_branches"    -r           report average latency per command    -s NUM       report this scale factor in output    -S           perform SELECT-only transactions    -t NUM       number of transactions each client runs (default: 10)    -T NUM       duration of benchmark test in seconds    -v           vacuum all four standard tables before tests    Common options:    -d           print debugging output    -h HOSTNAME  database server host or socket directory    -p PORT      database server port number    -U USERNAME  connect as specified database user    --help       show this help, then exit    --version    output version information, then exit    Report bugs to .

3.初始化测试数据

[postgres@localhost  ~]$ pgbench -i pgbench  creating tables...  10000 tuples done.  20000 tuples done.  30000 tuples done.  40000 tuples done.  50000 tuples done.  60000 tuples done.  70000 tuples done.  80000 tuples done.  90000 tuples done.  100000 tuples done.  set primary key...  NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "pgbench_branches_pkey" for table "pgbench_branches"  NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "pgbench_tellers_pkey" for table "pgbench_tellers"  NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "pgbench_accounts_pkey" for table "pgbench_accounts"  vacuum...done.  [postgres@localhost  ~]$ psql -d pgbench  psql (9.1.2)  Type "help" for help.    pgbench=# select count(1) from pgbench_accounts;   count    --------   100000  (1 row)    pgbench=# select count(1) from pgbench_branches;   count   -------       1  (1 row)    pgbench=# select count(1) from pgbench_history;   count   -------       0  (1 row)    pgbench=# select count(1) from pgbench_tellers;   count   -------      10  (1 row)    pgbench=# \d+ pgbench_accounts                  Table "public.pgbench_accounts"    Column  |     Type      | Modifiers | Storage  | Description   ----------+---------------+-----------+----------+-------------   aid      | integer       | not null  | plain    |    bid      | integer       |           | plain    |    abalance | integer       |           | plain    |    filler   | character(84) |           | extended |   Indexes:      "pgbench_accounts_pkey" PRIMARY KEY, btree (aid)  Has OIDs: no  Options: fillfactor=100    pgbench=# \d+ pgbench_branches                  Table "public.pgbench_branches"    Column  |     Type      | Modifiers | Storage  | Description   ----------+---------------+-----------+----------+-------------   bid      | integer       | not null  | plain    |    bbalance | integer       |           | plain    |    filler   | character(88) |           | extended |   Indexes:      "pgbench_branches_pkey" PRIMARY KEY, btree (bid)  Has OIDs: no  Options: fillfactor=100    pgbench=# \d+ pgbench_history                         Table "public.pgbench_history"   Column |            Type             | Modifiers | Storage  | Description   --------+-----------------------------+-----------+----------+-------------   tid    | integer                     |           | plain    |    bid    | integer                     |           | plain    |    aid    | integer                     |           | plain    |    delta  | integer                     |           | plain    |    mtime  | timestamp without time zone |           | plain    |    filler | character(22)               |           | extended |   Has OIDs: no    pgbench=# \d+ pgbench_tellers                   Table "public.pgbench_tellers"    Column  |     Type      | Modifiers | Storage  | Description   ----------+---------------+-----------+----------+-------------   tid      | integer       | not null  | plain    |    bid      | integer       |           | plain    |    tbalance | integer       |           | plain    |    filler   | character(84) |           | extended |   Indexes:      "pgbench_tellers_pkey" PRIMARY KEY, btree (tid)  Has OIDs: no  Options: fillfactor=100

说明：
a.这里使用的是默认的参数值,带-s 参数时可指定测试数据的数据量,-f可以指定测试的脚本,这里用的是默认脚本
b.不要在生产的库上做，新建一个测试库，当生产上有同名的测试表时将被重置

4.测试过程 
4.1 1个session

[postgres@localhost  ~]$ nohup pgbench -c 1 -T 20 -r pgbench > file.out  2>&1  [postgres@localhost  ~]$ more file.out   nohup: ignoring input  starting vacuum...end.  transaction type: TPC-B (sort of)  scaling factor: 1  query mode: simple  number of clients: 1  number of threads: 1  duration: 20 s  number of transactions actually processed: 12496                                                     tps = 624.747958 (including connections establishing)                                                tps = 625.375564 (excluding connections establishing)  statement latencies in milliseconds:          0.005299        \set nbranches 1 * :scale          0.000619        \set ntellers 10 * :scale          0.000492        \set naccounts 100000 * :scale          0.000700        \setrandom aid 1 :naccounts          0.000400        \setrandom bid 1 :nbranches          0.000453        \setrandom tid 1 :ntellers          0.000430        \setrandom delta -5000 5000          0.050707        BEGIN;          0.200909        UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;          0.098718        SELECT abalance FROM pgbench_accounts WHERE aid = :aid;          0.111621        UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;          0.107297        UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;          0.095156        INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);          0.919101        END;

4.2 30个session

[postgres@localhost  ~]$nohup pgbench -c 30 -T 20 -r pgbench > file.out  2>&1  [postgres@localhost  ~]$ more file.out   nohup: ignoring input  starting vacuum...end.  transaction type: TPC-B (sort of)  scaling factor: 1  query mode: simple  number of clients: 30  number of threads: 1  duration: 20 s  number of transactions actually processed: 8056                                                      tps = 399.847446 (including connections establishing)                                                tps = 404.089024 (excluding connections establishing)  statement latencies in milliseconds:      0.004195        \set nbranches 1 * :scale      0.000685        \set ntellers 10 * :scale      0.000887        \set naccounts 100000 * :scale      0.000805        \setrandom aid 1 :naccounts      0.000656        \setrandom bid 1 :nbranches      0.000523        \setrandom tid 1 :ntellers      0.000499        \setrandom delta -5000 5000      0.515565        BEGIN;      0.865217        UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;      0.307207        SELECT abalance FROM pgbench_accounts WHERE aid = :aid;      50.543371       UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;      19.210089       UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;      0.384190        INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);      2.116383        END;

4.3 50个session

[postgres@localhost  ~]$nohup pgbench -c 50 -T 20 -r pgbench > file.out  2>&1  [postgres@localhost  ~]$ more file.out   nohup: ignoring input  starting vacuum...end.  transaction type: TPC-B (sort of)  scaling factor: 1  query mode: simple  number of clients: 50  number of threads: 1  duration: 20 s  number of transactions actually processed: 7504                                                      tps = 370.510431 (including connections establishing)                                                tps = 377.964565 (excluding connections establishing)  statement latencies in milliseconds:          0.004291        \set nbranches 1 * :scale          0.000769        \set ntellers 10 * :scale          0.000955        \set naccounts 100000 * :scale          0.000865        \setrandom aid 1 :naccounts          0.000513        \setrandom bid 1 :nbranches          0.000580        \setrandom tid 1 :ntellers          0.000522        \setrandom delta -5000 5000          0.604671        BEGIN;          1.480723        UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;          0.401148        SELECT abalance FROM pgbench_accounts WHERE aid = :aid;          104.713566      UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;          21.562787       UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;          0.412209        INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);          2.243497        END;

4.4 100个session
超过100个会报错，因为数据库当前设置最大session是100

[postgres@localhost  ~]$ nohup pgbench -c 100 -T 20 -r pgbench> file.out  2>&1  [postgres@localhost  ~]$ more file.out   nohup: ignoring input  starting vacuum...end.  transaction type: TPC-B (sort of)  scaling factor: 1  query mode: simple  number of clients: 100  number of threads: 1  duration: 20 s  number of transactions actually processed: 6032                                                      tps = 292.556692 (including connections establishing)                                                tps = 305.595090 (excluding connections establishing)  statement latencies in milliseconds:          0.004508        \set nbranches 1 * :scale          0.000787        \set ntellers 10 * :scale          0.000879        \set naccounts 100000 * :scale          0.001620        \setrandom aid 1 :naccounts          0.000485        \setrandom bid 1 :nbranches          0.000561        \setrandom tid 1 :ntellers          0.000656        \setrandom delta -5000 5000          3.660809        BEGIN;          4.198062        UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;          1.727076        SELECT abalance FROM pgbench_accounts WHERE aid = :aid;          281.955832      UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;          27.054125       UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;          0.524155        INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);          2.710619        END;

5.说明
我们主要关心的是最后的输出报告中的TPS值，里面有两个,一个是包含网络开销(including),另一个是不包含网络开销的 (excluding),这个值是反映的每秒处理的事务数，反过来也可以查出每个事务数所消耗的平均时间，一般认为能将硬件用到极致，速度越快越好。

参考：http://www.postgresql.org/docs/9.1/static/pgbench.html