read aggregate functions from database

public/app/plugins/datasource/postgres/postgres_query.ts

@@ -24,9 +24,10 @@ export default class PostgresQuery {
     target.where = target.where || [];
     target.select = target.select || [[{ type: 'column', params: ['value'] }]];
 
-    this.updateProjection();
     // give interpolateQueryStr access to this
     this.interpolateQueryStr = this.interpolateQueryStr.bind(this);
+
+    this.updateProjection();
   }
 
   quoteIdentifier(value) {

public/app/plugins/datasource/postgres/query_ctrl.ts

@@ -77,9 +77,19 @@ export class PostgresQueryCtrl extends QueryCtrl {
     });
     this.panelCtrl.events.on('data-received', this.onDataReceived.bind(this), $scope);
     this.panelCtrl.events.on('data-error', this.onDataError.bind(this), $scope);
+
   }
 
   buildSelectMenu() {
+
+    if (!queryPart.hasAggregates()) {
+      this.datasource.metricFindQuery(this.queryBuilder.buildAggregateQuery())
+        .then(results => {
+          queryPart.clearAggregates();
+          _.map(results, segment => { queryPart.registerAggregate(segment.text); });
+        })
+        .catch(this.handleQueryError.bind(this));
+    }
     var categories = queryPart.getCategories();
     this.selectMenu = _.reduce(
       categories,
@@ -279,6 +289,7 @@ export class PostgresQueryCtrl extends QueryCtrl {
         var datatype = results[0].text;
         switch (datatype) {
           case "text":
+          case "character":
           case "character varying":
             return this.$q.when(this.uiSegmentSrv.newOperators(['=', '!=', '~', '~*','!~','!~*','IN']));
           default:

public/app/plugins/datasource/postgres/query_part.ts

@@ -23,6 +23,17 @@ function register(options: any) {
   options.category.push(index[options.type]);
 }
 
+function registerAggregate(name: string) {
+  register({
+    type: name,
+    addStrategy: replaceAggregationAddStrategy,
+    category: categories.Aggregations,
+    params: [],
+    defaultParams: [],
+    renderer: functionRenderer,
+  });
+}
+
 var groupByTimeFunctions = [];
 
 function aliasRenderer(part, innerExpr) {
@@ -192,6 +203,12 @@ register({
 
 export default {
   create: createPart,
+  registerAggregate: registerAggregate,
+  clearAggregates: function() { categories.Aggregations = []; },
+  hasAggregates: function() {
+    // FIXME
+    return categories.Aggregations.length > 6;
+  },
   getCategories: function() {
     return categories;
   },