我对独角兽，Sidekiq和数据库池大小的理解正确吗？ [英] Is my understanding of Unicorn, Sidekiq and DB Pool size correct?

问题描述

我有独角兽，Sidekiq和Postgres设置。

I have Unicorn, Sidekiq and Postgres setup.

我试图了解要设置的正确配置，以免达到最大数据库连接限制。在Opsworks中，m1.small Postgres RDS实例最多可具有121个连接。

I am trying to understand the right configuration to set up so that I don't hit the maximum db connection limit. In Opsworks, the m1.small Postgres RDS instance can have a max of 121 connections.

我的数据库池大小为5。

I have a db pool size of 5.

考虑一下。 Sidekiq和Unicorn是它自己的过程。因此，每个进程的数据库池大小为5。如果我的理解错误，请纠正我。

Consider this. Sidekiq and Unicorn are its own process. So the db pool size for each process is 5. Correct me if my understanding here is wrong.

如果我有5个独角兽进程，这意味着5 * 5 = 25个数据库连接

If I have 5 unicorn process', that means 5*5=25 database connections

现在这是我有点困惑的部分，因为Sidekiq是多线程的。如果Sidekiq的并发性为5，并且数据库池大小也设置为5。这是否也意味着在给定的时间有25个潜在的数据库连接？

Now this is the part where I am slightly confused, since Sidekiq is multithreaded. If Sidekiq has a concurrency of 5. and the db pool size is also set to 5. Does that mean 25 potential db connections at a given time too?

这意味着，例如，我可能有50个数据库连接？

This means, for one instance, I could have 50 db connections?

推荐答案

在Unicorn中，每个进程都建立自己的连接池，因此，如果您的数据库池设置为5，并且您有5个Unicorn worker，则最多可以有25个连接。但是，由于每个独角兽工作者一次只能处理一个连接，因此除非您的应用在内部使用线程，否则每个工作者只会实际使用一个数据库连接。

In Unicorn each process establishes its own connection pool, so you if your db pool setting is 5 and you have 5 Unicorn workers then you can have up to 25 connections. However, since each unicorn worker can handle only one connection at a time, then unless your app uses threading internally each worker will only actually use one db connection.

在Sidekiq中，池中的连接在线程之间共享，因此每个工作人员至少需要一个连接。如果您的并发数为5，则您的池必须至少为5。

In Sidekiq, the connections in the pool are shared across threads, so you need to have at least one connection available per worker. If you have a concurrency of 5, then your pool needs to be at least 5.

池的大小大于1意味着每个Unicorn工作者都可以访问连接

Having a pool size greater than 1 means each Unicorn worker has access to connections it can't use, but it won't actually open the connections, so that doesn't matter.

您的应用程序需要的实际连接总数，除非您不使用，但实际上并不会打开连接，因此没关系。在您的应用程序代码中使用线程（并且它们不共享db连接），每个Sidekiq工作者一个线程，每个Unicorn工作者一个线程。

The total number of actual connections your app requires, unless you're using threads in your application code (and they don't share a db connection), is one per Sidekiq worker plus one per Unicorn worker.

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