todosapp: Use query for getting lists.
Makes getting lists 3 to 4 times faster on example data.
Change-Id: I748ff36162f0f9f4fbd82e90ef23d1a13b7844f9
diff --git a/browser/syncbase_dispatcher.js b/browser/syncbase_dispatcher.js
index 9da0e77..103ff4e 100644
--- a/browser/syncbase_dispatcher.js
+++ b/browser/syncbase_dispatcher.js
@@ -124,17 +124,12 @@
// SyncbaseDispatcher impl
// Returns list objects without 'sg' fields.
-// TODO(sadovsky): Use a query for better performance. It should be possible to
-// query based on row key regexp.
define('getListsOnly_', function(ctx, cb) {
- this.getRows_(ctx, null, function(err, rows) {
+ this.getRowsQuery_(ctx, 'k not like "%' + SEP + '%"', function(err, rows) {
if (err) return cb(err);
- var lists = [];
- _.forEach(rows, function(row) {
- if (row.key.indexOf(SEP) >= 0) {
- return; // ignore nested (and therefore non-list) records
- }
- lists.push(_.assign(unmarshal(row.value), {_id: row.key}));
+ var lists = _.map(rows, function(row) {
+ console.assert(!row.key.includes(SEP));
+ return _.assign(unmarshal(row.value), {_id: row.key});
});
return cb(null, lists);
});
@@ -492,7 +487,7 @@
tb.put(ctx, tagKey(todoId, tag), null, cb);
});
-// Returns all rows in the table.
+// Returns all rows in the table with the given key prefix.
define('getRows_', function(ctx, prefix, cb) {
var rows = [], streamErr = null;
var range = nosql.rowrange.prefix(prefix || '');
@@ -507,6 +502,22 @@
});
});
+// Returns all rows in the table matching the where clause.
+define('getRowsQuery_', function(ctx, where, cb) {
+ var rows = [], streamErr = null;
+ var q = 'select k, v from ' + this.tb_.name + ' where ' + where;
+ this.db_.exec(ctx, q, function(err) {
+ if (err) return cb(err);
+ if (streamErr) return cb(streamErr);
+ rows = rows.slice(1); // remove header
+ cb(null, rows);
+ }).on('data', function(row) {
+ rows.push({key: row[0], value: row[1]});
+ }).on('error', function(err) {
+ streamErr = streamErr || err.error;
+ });
+});
+
// Performs a read-modify-write on key, applying updateFn to the value.
// Takes care of value marshalling and unmarshalling.
// TODO(sadovsky): Atomic read-modify-write requires 4 RPCs. MongoDB-style API
