Sketch of vector overviews support

2016-01-19 19:31:43 +01:00
parent 216e7b7f1d
commit 89590d32df
3 changed files with 119 additions and 0 deletions
@@ -0,0 +1,65 @@
+var queue = require('queue-async');
+var QueryTablesApi = require('./query_tables_api');
+
+function OverviewsApi(pgQueryRunner) {
+   if (pgQueryRunner.pgQueryRunner != null) {
+       this.queryTablesApi = pgQueryRunner;
+       this.pgQueryRunner = this.queryTablesApi.pgQueryRunner;
+   } else {
+       this.pgQueryRunner = pgQueryRunner;
+       this.queryTablesApi = new QueryTablesApi(pgQueryRunner);
+  }
+}
+
+module.exports = OverviewsApi;
+
+OverviewsApi.prototype.getOverviewsMetadata = function (username, sql, callback) {
+    this.queryTablesApi.getAffectedTablesInQuery(username, sql, function(err, tableNames){
+        if (err) {
+            callback(err);
+        } else {
+            metadata = {};
+
+            var parallelism = 2;
+            var q = queue(parallelism);
+
+            for ( var i=0; i < tableNames.length; ++i ) {
+                (function(tableName) {
+                    q.defer(function(done){
+                        var sql = "SELECT * FROM CDB_Overviews('" + tableName + "');";
+                        this.pgQueryRunner.run(username, query, handleOverviewsRows, function(err, table_metadata){
+                            if (err) {
+                                done(err);
+                            } else {
+                                metadata[tableName] = table_metadata;
+                                done(null);
+                            }
+                        });
+                    });
+                }(tableNames[i]));
+            }
+
+            q.awaitAll(function(err, results){
+              if (err) {
+                  return callback(err);
+              } else {
+                  return callback(null, metadata);
+              }
+            });
+        };
+    });
+};
+
+function handleOverviewsRows(err, rows, callback) {
+    if (err){
+        var msg = err.message ? err.message : err;
+        callback(new Error('could not get overviews metadata: ' + msg));
+        return;
+    }
+    var metadata = {};
+    for ( var i=0; i<rows.length; ++i ) {
+      var row = rows[i];
+      metadata[row.z] = { table: row.overview_table };
+    };
+    callback(null, metadata);
+}