pg-promise中的查询超时 [英] Query timeout in pg-promise
问题描述
我想向pg-promise查询添加超时,因此如果数据库尚未响应,则它们将在一段时间后失败。
是否有任何建议的方法可以做到这一点,或者我应该制作自定义包装来处理计时器并在太晚时拒绝promise?
来自 pg-promise ...
pg-promise 不支持查询取消,因为它可以解决数据库设计错误或查询执行不正确的问题。
PostgreSQL支持事件在执行耗时的查询时应使用该函数,因此无需等待,可以将事件侦听器设置为在特定数据/视图可用时触发。参见 LISTEN / NOTIFY 示例。
您可以扩展 pg-promise 使用您自己的自定义查询方法,该方法将因拒绝而超时(请参见下面的示例),但这还是设计问题之外的另一种解决方法。
使用蓝鸟的示例:
const Promise = require('bluebird');
Promise.config({
cancel:true
});
const initOptions = {
promiseLib:承诺,
extend(obj){
obj.queryTimeout =(查询,值,延迟)=> ; {
return obj.any(query,values).timeout(delay);
}
}
};
const pgp = require(’pg-promise’)(initOptions);
const db = pgp(/ *连接详细信息* /);
然后您可以使用 db.queryTimeout(query,values,delay)
在每个级别上。
或者,如果您使用的是蓝鸟 ,您可以将 .timeout(delay)
链接到任何现有方法:
db.any(查询,值)
.timeout(500)
.then(数据=> {})
.catch(错误=> {})
另请参见:
更新
从版本 8.5.3 , pg-promise 开始通过属性 query_time支持查询超时
您可以覆盖默认值:
pgp.pg.defaults.query_timeout = 3000; // 3秒后每个查询超时
或在连接对象中指定该查询:
const db = pgp({
/ *所有连接详细信息* /
query_timeout:3000
});
I want to add timeout to pg-promise queries so they will fail after some amount of time if database have not yet responded. Is there any recommended way to do that or should I make custom wrapper that will handle timer and reject promise if it's too late?
From the author of pg-promise...
pg-promise doesn't support query cancellation, because it is a hack to work-around incorrect database design or bad query execution.
PostgreSQL supports events that should be used when executing time-consuming queries, so instead of waiting, one can set an event listener to be triggered when specific data/view becomes available. See LISTEN/NOTIFY example.
You can extend pg-promise with your own custom query method that will time out with a reject (see example below), but that's again another work-around on top of a design problem.
Example using Bluebird:
const Promise = require('bluebird');
Promise.config({
cancellation: true
});
const initOptions = {
promiseLib: Promise,
extend(obj) {
obj.queryTimeout = (query, values, delay) => {
return obj.any(query, values).timeout(delay);
}
}
};
const pgp = require('pg-promise')(initOptions);
const db = pgp(/* connection details */);
Then you can use db.queryTimeout(query, values, delay)
on every level.
Alternatively, if you are using Bluebird, you can chain .timeout(delay)
to any of the existing methods:
db.any(query, values)
.timeout(500)
.then(data => {})
.catch(error => {})
See also:
- extend event
- Bluebird.timeout
UPDATE
From version 8.5.3, pg-promise started supporting query timeouts, via property query_timeout
within the connection object.
You can either override the defaults:
pgp.pg.defaults.query_timeout = 3000; // timeout every query after 3 seconds
Or specify it within the connection object:
const db = pgp({
/* all connection details */
query_timeout: 3000
});
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