WIP implemented date histogram

lib/cartodb/backends/dataview.js

@@ -20,6 +20,8 @@ function DataviewBackend(analysisBackend) {
     this.analysisBackend = analysisBackend;
 }
 
+var DATE_AGGREGATIONS = ['minute', 'hour', 'day', 'week', 'month', 'year'];
+
 module.exports = DataviewBackend;
 
 DataviewBackend.prototype.getDataview = function (mapConfigProvider, user, params, callback) {
@@ -30,6 +32,7 @@ DataviewBackend.prototype.getDataview = function (mapConfigProvider, user, param
             mapConfigProvider.getMapConfig(this);
         },
         function runDataviewQuery(err, mapConfig) {
+            /* jshint maxcomplexity: 7 */
             assert.ifError(err);
 
             var dataviewDefinition = getDataviewDefinition(mapConfig.obj(), dataviewName);
@@ -88,6 +91,10 @@ DataviewBackend.prototype.getDataview = function (mapConfigProvider, user, param
                 {ownFilter: ownFilter}
             );
 
+            if (params.aggregation && DATE_AGGREGATIONS.indexOf(params.aggregation) !== -1) {
+                overrideParams.aggregation = params.aggregation;
+            }
+
             var dataview = dataviewFactory.getDataview(query, dataviewDefinition);
             dataview.getResult(pg, overrideParams, this);
         },

lib/cartodb/controllers/base.js

@@ -25,6 +25,7 @@ var REQUEST_QUERY_PARAMS_WHITELIST = [
     'start', // number
     'end', // number
     'column_type', // string
+    'aggregation', //string
     // widgets search
     'q'
 ];

lib/cartodb/models/dataview/histogram.js

@@ -8,7 +8,7 @@ dot.templateSettings.strip = false;
 var columnTypeQueryTpl = dot.template(
     'SELECT pg_typeof({{=it.column}})::oid FROM ({{=it.query}}) _cdb_histogram_column_type limit 1'
 );
-var columnCastTpl = dot.template("date_part('epoch', {{=it.column}})");
+// var columnCastTpl = dot.template("date_part('epoch', {{=it.column}})");
 
 var BIN_MIN_NUMBER = 6;
 var BIN_MAX_NUMBER = 48;
@@ -71,7 +71,7 @@ var overrideBinsQueryTpl = dot.template([
 var nullsQueryTpl = dot.template([
     'nulls AS (',
     '  SELECT',
-    '  count(*) AS nulls_count',
+    '    count(*) AS nulls_count',
     '  FROM ({{=it._query}}) _cdb_histogram_nulls',
     '  WHERE {{=it._column}} IS NULL',
     ')'
@@ -97,6 +97,52 @@ var histogramQueryTpl = dot.template([
     'ORDER BY bin'
 ].join('\n'));
 
+var dateBasicsQueryTpl = dot.template([
+    'basics AS (',
+    '    SELECT',
+    '        max(date_part(\'epoch\', {{=it._column}})) AS max_val,',
+    '        min(date_part(\'epoch\', {{=it._column}})) AS min_val,',
+    '        avg(date_part(\'epoch\', {{=it._column}})) AS avg_val,',
+    '        min(date_trunc(\'{{=it._aggregation}}\', {{=it._column}})) AS start_date,',
+    '        max({{=it._column}}) AS end_date,',
+    '        count(1) AS total_rows',
+    '    FROM ({{=it._query}}) _cdb_basics',
+    ')'
+].join(' \n'));
+
+var dateBinsQueryTpl = dot.template([
+    'bins AS (',
+    '    SELECT',
+    '        bins_array,',
+    '        ARRAY_LENGTH(bins_array, 1) AS bins_number',
+    '    FROM (',
+    '       SELECT',
+    '           ARRAY(',
+    '               SELECT GENERATE_SERIES(start_date, end_date, \'1 {{=it._aggregation}}\'::interval)',
+    '           ) AS bins_array',
+    '       FROM basics',
+    '    ) _cdb_bins_array',
+    ')'
+].join('\n'));
+
+var dateHistogramQueryTpl = dot.template([
+    'SELECT',
+    '    (max_val - min_val) / cast(bins_number as float) AS bin_width,',
+    '    bins_number,',
+    '    nulls_count,',
+    '    CASE WHEN min_val = max_val',
+    '      THEN 0',
+    '      ELSE GREATEST(1, LEAST(WIDTH_BUCKET({{=it._column}}, bins_array), bins_number)) - 1',
+    '    END AS bin,',
+    '    min(date_part(\'epoch\', {{=it._column}}))::numeric AS min,',
+    '    max(date_part(\'epoch\', {{=it._column}}))::numeric AS max,',
+    '    avg(date_part(\'epoch\', {{=it._column}}))::numeric AS avg,',
+    '    count(*) AS freq',
+    'FROM ({{=it._query}}) _cdb_histogram, basics, bins, nulls',
+    'WHERE date_part(\'epoch\', {{=it._column}}) IS NOT NULL',
+    'GROUP BY bin, bins_number, bin_width, nulls_count, avg_val',
+    'ORDER BY bin'
+].join('\n'));
 
 var TYPE = 'histogram';
 
@@ -118,6 +164,7 @@ function Histogram(query, options, queries) {
     this.queries = queries;
     this.column = options.column;
     this.bins = options.bins;
+    this.aggregation = options.aggregation;
 
     this._columnType = null;
 }
@@ -163,7 +210,7 @@ Histogram.prototype.sql = function(psql, override, callback) {
     }
 
     if (this._columnType === 'date') {
-        _column = columnCastTpl({column: _column});
+        return this._buildDateHistogramQuery(override, callback);
     }
 
     var _query = this.query;
@@ -211,7 +258,6 @@ Histogram.prototype.sql = function(psql, override, callback) {
         }
     }
 
-
     var histogramSql = [
         "WITH",
         [
@@ -233,6 +279,48 @@ Histogram.prototype.sql = function(psql, override, callback) {
     return callback(null, histogramSql);
 };
 
+Histogram.prototype._buildDateHistogramQuery = function (override, callback) {
+    var _column = this.column;
+    var _query = this.query;
+    var _aggregation = override && override.aggregation ? override.aggregation : this.aggregation;
+
+    var dateBasicsQuery = dateBasicsQueryTpl({
+        _query: _query,
+        _column: _column,
+        _aggregation: _aggregation
+    });
+
+    var dateBinsQuery = [
+        dateBinsQueryTpl({
+            _aggregation: _aggregation
+        })
+    ].join(',\n');
+
+    var nullsQuery = nullsQueryTpl({
+        _query: _query,
+        _column: _column
+    });
+
+    var dateHistogramQuery = dateHistogramQueryTpl({
+        _query: _query,
+        _column: _column
+    });
+
+    var histogramSql = [
+        "WITH",
+        [
+            dateBasicsQuery,
+            dateBinsQuery,
+            nullsQuery
+        ].join(',\n'),
+        dateHistogramQuery
+    ].join('\n');
+
+    debug(histogramSql);
+
+    return callback(null, histogramSql);
+};
+
 Histogram.prototype.format = function(result, override) {
     override = override || {};
     var buckets = [];