PostgreSQL11previewpgbench支持大于1000链接(ppoll()代替select())

作者

digoal

日期

2018-03-25

标签

PostgreSQL , pgbench , ppoll

背景

目前pgbench最大可以测试1000个连接，显然在某些时候是不够的，我们可能需要建立更多的连接进行测试。

$ pgbench -j 3000 -c 1500
invalid number of clients: "1500"

使用这里提到的方法修改一下pgbench，让它能够建立100万个连接。

《从PostgreSQL支持100万个连接聊起》

PostgreSQL 11这块会改掉，使用ppoll代替select，超过1000个连接。

```

[trying again for 2018-01]

This patch enables building pgbench to use ppoll() instead of select()

to allow for more than (FD_SETSIZE - 10) connections. As implemented,

when using ppoll(), the only connection limitation is system resources.

The patch has been implemented to introduce a minimal of #ifdef/#ifndef

clutter in the code.

Without this patch, one is limited to '(FD_SETSIZE - 10)’ number of connections.

Example of something that fails without this patch but works with the patch:

Without the patch:

$ pgbench -j 3000 -c 1500

invalid number of clients: "1500"

With the patch:

$ pgbench -j 3000 -c 1500

starting vacuum...end.

transaction type:

scaling factor: 2000

query mode: simple

number of clients: 1500

number of threads: 1500

number of transactions per client: 10

number of transactions actually processed: 15000/15000

latency average = 631.730 ms

tps = 2374.430587 (including connections establishing)

tps = 4206.524986 (excluding connections establishing)

doug

Doug Rady

Amazon Aurora, RDS PostgreSQL

radydoug(at)amazon(dot)com

```

参考

https://www.postgresql.org/message-id/flat/3B729131-C891-41F3-B911-8DEB05515D63@amazon.com#3B729131-C891-41F3-B911-8DEB05515D63@amazon.com

https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=60e612b602999e670f2d57a01e52799eaa903ca9

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