pgbench使用记录

1.初始化：

　　pgbench -i pgbench

　　如果端口号有变化，需要先手动创建数据库，再执行。

　　pgbench -i -s 10 -p 5433 pgbench

　重点：主要用到两个参数，-i：初始化模式，-s 插入的倍数，默认是1，即插入100000条；也就是执行多少次generate_series(1,100000)。

2.开始测试：

　　pgbench -c 96  -j 12 -T 20 -r -p 5433 pgbench

-bash-4.1$ pgbench -c 96  -j 12 -T 20 -r -p 5433 pgbench
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor:
query mode: simple
number of clients:
number of threads:
duration:  s
number of transactions actually processed:
latency average: 1345.443 ms
tps = 71.351954 (including connections establishing)
tps = 71.400363 (excluding connections establishing)
statement latencies in milliseconds:
        0.003744        \set nbranches  * :scale
        0.001051        \set ntellers  * :scale
        0.000855        \set naccounts  * :scale
        0.001345        \setrandom aid  :naccounts
        0.000850        \setrandom bid  :nbranches
        0.000680        \setrandom tid  :ntellers
        0.000797        \setrandom delta -
        0.425127        BEGIN;
        3.685616        UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;
        0.189167        SELECT abalance FROM pgbench_accounts WHERE aid = :aid;
        1144.710503     UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;
        121.211975      UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;
        0.194937        INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);
        13.740971       END;

　　主要参数：

　　-c 总连接数，创建多少个连接到数据库，一般数据库接受连接数默认为100，其中需要预留3个左右的连接。

　　-j 进程数量，每个进程创建n个连接，那么就存在如下关系：－c ＝ －j ＊n。

　　-T 测试持续时间，指定了-T就不能指定-t,每个连接执行的事物数量。即，要么指定测试多长时间，要么指定测试多少个事物。

　　-r 显示每一步操作的平均时间。

　　-f 指定测试脚本，不指定则使用默认脚本。

3.测试结果分析

　　可以看看设置的参数，也可以看到TPS，当然可以算到QPS，也可以看到系统的读写更新的速度，知道该往哪方面优化。

4.pgbench初始化参数：

 

pgbench accepts the following command-line initialization arguments: 

-F fillfactor
Create the pgbench_accounts, pgbench_tellers and pgbench_branches tables with the given fillfactor. Default is . 

-i
Required to invoke initialization mode. 

-s scale_factor
Multiply the number of rows generated by the scale factor. For example, -s  will create ,, rows in the pgbench_accounts table. Default is . 

5.pgbench 压力测试参数：

pgbench accepts the following command-line benchmarking arguments: 

-c clients
Number of clients simulated, that is, number of concurrent database sessions. Default is . 

-C
Establish a new connection for each transaction, rather than doing it just once per client session. This is useful to measure the connection overhead. 

-d
Print debugging output. 

-D varname=value
Define a variable for use by a custom script (see below). Multiple -D options are allowed. 

-f filename
Read transaction script from filename. See below for details. -N, -S, and -f are mutually exclusive. 

-j threads
Number of worker threads within pgbench. Using more than one thread can be helpful on multi-CPU machines. The number of clients must be a multiple of the number of threads, since each thread is given the same number of client sessions to manage. Default is . 

-l
Write the time taken by each transaction to a log file. See below for details. 

-M querymode
Protocol to use for submitting queries to the server: 

simple: use simple query protocol.

extended: use extended query protocol.

prepared: use extended query protocol with prepared statements.

The default is simple query protocol. (See Chapter  for more information.) 

-n
Perform no vacuuming before running the test. This option is necessary if you are running a custom test scenario that does not include the standard tables pgbench_accounts, pgbench_branches, pgbench_history, and pgbench_tellers. 

-N
Do not update pgbench_tellers and pgbench_branches. This will avoid update contention on these tables, but it makes the test case even less like TPC-B. 

-s scale_factor
Report the specified scale factor in pgbench is output. With the built-in tests, this is not necessary; the correct scale factor will be detected by counting the number of rows in the pgbench_branches table. However, when testing custom benchmarks (-f option), the scale factor will be reported as  unless this option is used. 

-S
Perform select-only transactions instead of TPC-B-like test. 

-t transactions
Number of transactions each client runs. Default is . 

-T seconds
Run the test for this many seconds, rather than a fixed number of transactions per client. -t and -T are mutually exclusive. 

-v
Vacuum all four standard tables before running the test. With neither -n nor -v, pgbench will vacuum the pgbench_tellers and pgbench_branches tables, and will truncate pgbench_history.

6.默认测试脚本：

\set nbranches :scale
\set ntellers  * :scale
\set naccounts  * :scale
\setrandom delta -
\setrandom aid  :naccounts
\setrandom bid  :nbranches
\setrandom tid  :ntellers

BEGIN;
UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;
SELECT abalance FROM pgbench_accounts WHERE aid = :aid;
UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;
UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;
INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);
END;

    备注：上面是 pgbench 自带的测试脚本，用户也可以自己编写测试脚本。

补充20190619：

7.在pg11上测试时，\setrandom报错，修改脚本：

\set nbranches :scale
\set ntellers  * :scale
\set naccounts  * :scale
\set delta random(-,)
\set aid random(,:naccounts)
\set bid random(,:nbranches)
\set tid random(,:ntellers)

BEGIN;
    UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;
    SELECT abalance FROM pgbench_accounts WHERE aid = :aid;
    UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;
    UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;
    INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);
END;

二、如果我们有绘图需要，一般可以这样解决：

1）使用pgbench 选用-P 选项，多少s报告一次进程的tps等信息，将这些信息可以放到excel或者Gnuplot、Matlab中绘图。

2）使用pgbench_tools来做综合测试，并给出一个趋势报告图。

下面是对pgbench_tools的介绍和使用：

https://github.com/kuang17/pgbench-tools

需要注意的是：

1）PG10修改了几个函数，例如pg_current_xlog_location变为了pg_current_wal_lsn。

2）在测试脚本中，\setrandom 需要对应的修改为\set xxx random(xxx, xxx)的方式。

3）在绘图时，需要先按照Gnuplot绘图工具及相关的字体。

yum install gnuplot -y

wget http://olea.org/paquetes-rpm//msttcore-fonts-2.0-6.noarch.rpm

rpm -ivh msttcore-fonts-2.0-6.noarch.rpm

修改/etc/profile或~/.bashrc，这样设置可以固定下来。

export GDFONTPATH="/usr/share/fonts/msttcore"

export GNUPLOT_DEFAULT_GDFONT="arial"

. /etc/profile