From a8c164432ab88be0484cd4ade7ab911aa87289d3 Mon Sep 17 00:00:00 2001
From: Cameron Sparr <cameronsparr@gmail.com>
Date: Sat, 19 Dec 2015 15:58:57 -0700
Subject: [PATCH] 0.3.0 Removing internal parallelism: postgresql

---
 plugins/postgresql/postgresql.go | 61 +++++++++-----------------------
 1 file changed, 16 insertions(+), 45 deletions(-)

diff --git a/plugins/postgresql/postgresql.go b/plugins/postgresql/postgresql.go
index 5da776cbd..eaefadb50 100644
--- a/plugins/postgresql/postgresql.go
+++ b/plugins/postgresql/postgresql.go
@@ -11,46 +11,32 @@ import (
 	_ "github.com/lib/pq"
 )
 
-type Server struct {
+type Postgresql struct {
 	Address        string
 	Databases      []string
 	OrderedColumns []string
 }
 
-type Postgresql struct {
-	Servers []*Server
-}
-
 var ignoredColumns = map[string]bool{"datid": true, "datname": true, "stats_reset": true}
 
 var sampleConfig = `
-  # specify servers via an array of tables
-  [[plugins.postgresql.servers]]
-
   # specify address via a url matching:
   #   postgres://[pqgotest[:password]]@localhost[/dbname]?sslmode=[disable|verify-ca|verify-full]
   # or a simple string:
   #   host=localhost user=pqotest password=... sslmode=... dbname=app_production
   #
-  # All connection parameters are optional. By default, the host is localhost
-  # and the user is the currently running user. For localhost, we default
-  # to sslmode=disable as well.
+  # All connection parameters are optional.
   #
   # Without the dbname parameter, the driver will default to a database
   # with the same name as the user. This dbname is just for instantiating a
   # connection with the server and doesn't restrict the databases we are trying
   # to grab metrics for.
   #
-
   address = "host=localhost user=postgres sslmode=disable"
 
   # A list of databases to pull metrics about. If not specified, metrics for all
   # databases are gathered.
-
-  # databases = ["app_production", "blah_testing"]
-
-  # [[plugins.postgresql.servers]]
-  # address = "influx@remoteserver"
+  # databases = ["app_production", "testing"]
 `
 
 func (p *Postgresql) SampleConfig() string {
@@ -65,42 +51,27 @@ func (p *Postgresql) IgnoredColumns() map[string]bool {
 	return ignoredColumns
 }
 
-var localhost = &Server{Address: "sslmode=disable"}
+var localhost = "host=localhost sslmode=disable"
 
 func (p *Postgresql) Gather(acc plugins.Accumulator) error {
-	if len(p.Servers) == 0 {
-		p.gatherServer(localhost, acc)
-		return nil
-	}
-
-	for _, serv := range p.Servers {
-		err := p.gatherServer(serv, acc)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func (p *Postgresql) gatherServer(serv *Server, acc plugins.Accumulator) error {
 	var query string
 
-	if serv.Address == "" || serv.Address == "localhost" {
-		serv = localhost
+	if p.Address == "" || p.Address == "localhost" {
+		p.Address = localhost
 	}
 
-	db, err := sql.Open("postgres", serv.Address)
+	db, err := sql.Open("postgres", p.Address)
 	if err != nil {
 		return err
 	}
 
 	defer db.Close()
 
-	if len(serv.Databases) == 0 {
+	if len(p.Databases) == 0 {
 		query = `SELECT * FROM pg_stat_database`
 	} else {
-		query = fmt.Sprintf(`SELECT * FROM pg_stat_database WHERE datname IN ('%s')`, strings.Join(serv.Databases, "','"))
+		query = fmt.Sprintf(`SELECT * FROM pg_stat_database WHERE datname IN ('%s')`,
+			strings.Join(p.Databases, "','"))
 	}
 
 	rows, err := db.Query(query)
@@ -111,13 +82,13 @@ func (p *Postgresql) gatherServer(serv *Server, acc plugins.Accumulator) error {
 	defer rows.Close()
 
 	// grab the column information from the result
-	serv.OrderedColumns, err = rows.Columns()
+	p.OrderedColumns, err = rows.Columns()
 	if err != nil {
 		return err
 	}
 
 	for rows.Next() {
-		err = p.accRow(rows, acc, serv)
+		err = p.accRow(rows, acc)
 		if err != nil {
 			return err
 		}
@@ -130,20 +101,20 @@ type scanner interface {
 	Scan(dest ...interface{}) error
 }
 
-func (p *Postgresql) accRow(row scanner, acc plugins.Accumulator, serv *Server) error {
+func (p *Postgresql) accRow(row scanner, acc plugins.Accumulator) error {
 	var columnVars []interface{}
 	var dbname bytes.Buffer
 
 	// this is where we'll store the column name with its *interface{}
 	columnMap := make(map[string]*interface{})
 
-	for _, column := range serv.OrderedColumns {
+	for _, column := range p.OrderedColumns {
 		columnMap[column] = new(interface{})
 	}
 
 	// populate the array of interface{} with the pointers in the right order
 	for i := 0; i < len(columnMap); i++ {
-		columnVars = append(columnVars, columnMap[serv.OrderedColumns[i]])
+		columnVars = append(columnVars, columnMap[p.OrderedColumns[i]])
 	}
 
 	// deconstruct array of variables and send to Scan
@@ -159,7 +130,7 @@ func (p *Postgresql) accRow(row scanner, acc plugins.Accumulator, serv *Server)
 		dbname.WriteString(string(dbnameChars[i]))
 	}
 
-	tags := map[string]string{"server": serv.Address, "db": dbname.String()}
+	tags := map[string]string{"server": p.Address, "db": dbname.String()}
 
 	fields := make(map[string]interface{})
 	for col, val := range columnMap {