PostgreSQL statistics for Go

This package contains helper functions to retrieve runtime statistcs of a
PostgreSQL DB server. The aim is to decouple the DB queries from Go
applications.

Statistics will always return as a list of structs where each statistic has its
own struct. The decision to do this instead of returning a list of
interface{} items was that this keeps type-safety and removes guesswork.

As of 2018-10-17, this package contains a couple of statistics. More will come
soon.

DSN & URLs

Please take note that URLs are not yet supported as database DSNs. Certain
statistics are only available on the databse of the currently active
connection. This means that in order to fetch statistics from all databases, a
new connection must be established per DB. gopgstats will reuse the DSN
which was used to create the Fetcher object and modify it as needed. This
modification is currently only coded for normal connection strings. Not for
URLs!

Usage

::

import (
    "database/sql"
    "github.com/exhuma/gopgstats"
    _ "github.com/lib/pq"
)

// Use a normal PostgreSQL DSN syntax here. Note that URLs are currently
// NOT supported!
dsn := "host=dbhost username=jdoe password=s3cr37"
db, err := sql.Open("postgres", dsn)
if err != nil {
    panic(err)
}

fmt.Println("--- Locks")
fetcher := gopgstats.MakeDefaultFetcher(db)
result, err := fetcher.Locks()
fmt.Println(err)
fmt.Println(result)

fmt.Println("--- Disk IO")
diskio, err := fetcher.DiskIOAll(dsn)
fmt.Println(err)
fmt.Println(diskio)