Update max open and idle postgresql connections. Update changelog.

Default max idle connections is documented as 2:
https://golang.org/pkg/database/sql/#DB.SetMaxIdleConns

cmd/lora-app-server/cmd/configfile.go

@@ -62,14 +62,19 @@ dsn="{{ .PostgreSQL.DSN }}"
 # App Server and / or applying migrations.
 automigrate={{ .PostgreSQL.Automigrate }}
 
-# Max open connections in the pool.
-# <= 0 means unlimited
+# Max open connections.
+#
+# This sets the max. number of open connections that are allowed in the
+# PostgreSQL connection pool (0 = unlimited).
 max_open_connections={{ .PostgreSQL.MaxOpenConnections }}
 
-# Max open connections in the pool.
-# Zero means defaultMaxIdleConns; negative means 0
+# Max idle connections.
+#
+# This sets the max. number of idle connections in the PostgreSQL connection
+# pool (0 = no idle connections are retained).
 max_idle_connections={{ .PostgreSQL.MaxIdleConnections }}
 
+
 # Redis settings
 #
 # Please note that Redis 2.6.0+ is required.

cmd/lora-app-server/cmd/root.go

@@ -38,8 +38,7 @@ func init() {
 	viper.SetDefault("general.password_hash_iterations", 100000)
 	viper.SetDefault("postgresql.dsn", "postgres://localhost/loraserver_as?sslmode=disable")
 	viper.SetDefault("postgresql.automigrate", true)
-	viper.SetDefault("postgresql.max_open_connections", -1)
-	viper.SetDefault("postgresql.max_idle_connections", 0)
+	viper.SetDefault("postgresql.max_idle_connections", 2)
 	viper.SetDefault("redis.url", "redis://localhost:6379")
 	viper.SetDefault("redis.max_idle", 10)
 	viper.SetDefault("redis.idle_timeout", 5*time.Minute)

docs/content/install/config.md

@@ -115,6 +115,18 @@ dsn="postgres://localhost/loraserver_as?sslmode=disable"
 # App Server and / or applying migrations.
 automigrate=true
 
+# Max open connections.
+#
+# This sets the max. number of open connections that are allowed in the
+# PostgreSQL connection pool (0 = unlimited).
+max_open_connections=0
+
+# Max idle connections.
+#
+# This sets the max. number of idle connections in the PostgreSQL connection
+# pool (0 = no idle connections are retained).
+max_idle_connections=2
+
 
 # Redis settings
 #

docs/content/overview/changelog.md

@@ -37,6 +37,10 @@ the timezone for aggregation and metrics retention.
 In the gateway list page, it is now possible to show a map showing all the
 gateways and their states.
 
+### Improvements
+
+* Add PostgreSQL max open / idle connections settings. ([#360](https://github.com/brocaar/lora-app-server/pull/360)
+
 ### Upgrading
 
 This release requires LoRa Server v3.3.0 or later (which will forward the