Postgred pg_notify/listen only working if channel name is lower case

Question

I've read https://www.postgresql.org/docs/9.6/static/sql-notify.html and the channel name is just described as an 'identifier'.

I'm using NodeJS and pg https://www.npmjs.com/package/pg to access postgres.

If I use a lower case word in both, e.g. pg_notify('foo', ... and LISTEN foo it works. I've tested all combinations:

pg_notify  LISTEN  outcome
lower      lower   works
lower      upper   works
upper      lower   fails
upper      upper   fails

Is this a bug, or is it a logical result of being an 'identifier'? (If so, should this be documented on pg_notify page?)

Answer 1

混乱来自于引号。单引号用于字符串，双引号用于标识符，如果您不使用混合大小写/从数字开始/或其他技巧，则可以跳到无。

当您运行pg_notify函数时，您将“foo”作为字符串参数传递，因此使用单引号，当您运行时，NOTIFY "Virtual"您使用Virtual通道名称 - 标识符，因此您需要"在此处使用。

所以当你回答自己时，改变

client.query("LISTEN 'Virtual'");

到

client.query('LISTEN "Virtual"');

修复了一个问题