Shared pools support¶

since 1.5.1

Sometimes, you may need to limit the number of connections for several users at once. A good example is splitting routes for application connections and those from human users, such as DBAs. The latter never connect simultaneously, so it's appropriate to limit their connections to a low number to avoid consuming too much of the max_connections quota.

You cannot achieve this with general rules, as each rule has its own pool. Instead, you need a shared pool.

Configuration¶

Suppose you have several users that you want to limit together: db1.dba1, db1.dba2, db2.dba1, and db2.dba2. You will need to define a shared_pool in the global section of your configuration file, then reference it by name in your rules. Here's an example:

shared_pool "idm" {
    pool_size 3
}

database "db1" {
    user "dba1" {
        shared_pool "idm"
        ...
    }

    user "dba2" {
        shared_pool "idm"
        ...
    }
}

database "db1" {
    user "dba1" {
        shared_pool "idm"
        ...
    }

    user "dba3" {
        shared_pool "idm"
        ...
    }
}

With this configuration, only 3 connections are available from those routes, and all others will be waiting, as per the standard rules.