[v11.0.x] Revert "Postgres: Switch the datasource plugin from lib/pq to pgx (#8… (#85517)

Revert "Postgres: Switch the datasource plugin from lib/pq to pgx (#8… (#85509)

Revert "Postgres: Switch the datasource plugin from lib/pq to pgx (#83768)"

This reverts commit ecd6de826a.

(cherry picked from commit 8159e1db3a)

Co-authored-by: Gábor Farkas <gabor.farkas@gmail.com>

pkg/tsdb/grafana-postgresql-datasource/postgres_snapshot_test.go

@@ -3,6 +3,7 @@ package postgres
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -48,6 +49,20 @@ func TestIntegrationPostgresSnapshots(t *testing.T) {
 		t.Skip()
 	}
 
+	getCnnStr := func() string {
+		host := os.Getenv("POSTGRES_HOST")
+		if host == "" {
+			host = "localhost"
+		}
+		port := os.Getenv("POSTGRES_PORT")
+		if port == "" {
+			port = "5432"
+		}
+
+		return fmt.Sprintf("user=grafanatest password=grafanatest host=%s port=%s dbname=grafanadstest sslmode=disable",
+			host, port)
+	}
+
 	sqlQueryCommentRe := regexp.MustCompile(`^-- (.+)\n`)
 
 	readSqlFile := func(path string) (string, string) {
@@ -134,34 +149,18 @@ func TestIntegrationPostgresSnapshots(t *testing.T) {
 				ConnMaxLifetime:     14400,
 				Timescaledb:         false,
 				ConfigurationMethod: "file-path",
-				Mode:                "disable",
-			}
-
-			host := os.Getenv("POSTGRES_HOST")
-			if host == "" {
-				host = "localhost"
-			}
-			port := os.Getenv("POSTGRES_PORT")
-			if port == "" {
-				port = "5432"
 			}
 
 			dsInfo := sqleng.DataSourceInfo{
-				JsonData: jsonData,
-				DecryptedSecureJSONData: map[string]string{
-					"password": "grafanatest",
-				},
-				URL:      host + ":" + port,
-				Database: "grafanadstest",
-				User:     "grafanatest",
+				JsonData:                jsonData,
+				DecryptedSecureJSONData: map[string]string{},
 			}
 
 			logger := log.New()
 
-			settings := backend.DataSourceInstanceSettings{}
-			proxyClient, err := settings.ProxyClient(context.Background())
-			require.NoError(t, err)
-			db, handler, err := newPostgres("error", 10000, dsInfo, logger, proxyClient)
+			cnnstr := getCnnStr()
+
+			db, handler, err := newPostgres(context.Background(), "error", 10000, dsInfo, cnnstr, logger, backend.DataSourceInstanceSettings{})
 
 			t.Cleanup((func() {
 				_, err := db.Exec("DROP TABLE tbl")