[pgsql]: update of {aggregator_feed}.image violates not-null constraint

Bug as title. Will generate PDOException message as below:

[Thu Oct 09 00:49:06 2008] [error] [client 192.168.93.21] PHP Fatal error:  Uncaught exception 'PDOException' with message 'UPDATE {aggregator_feed} SET url = ?, checked = ?, link = ?, description = ?, image = ?, hash = ?, etag = ?, modified = ? WHERE fid = ? - \nArray\n(\n    [0] => http://192.168.93.21/projects/benchmarking/drupal-7.x-dev/rss.xml?feed=simpletest_aggregator_cpOLbze3WP\n    [1] => 1223484545\n    [2] => http://192.168.93.21/projects/benchmarking/drupal-7.x-dev\n    [3] => \n    [4] => \n    [5] => a5323f875483d5b5949e9cf6d65b242c\n    [6] => \n    [7] => 1223484545\n    [8] => 1\n)\nSQLSTATE[23502]: Not null violation: 7 ERROR:  null value in column "image" violates not-null constraint' in /var/www/projects/drupal/drupal-7.x-dev/includes/database/pgsql/database.inc:72\nStack trace:\n#0 /var/www/projects/drupal/drupal-7.x-dev/includes/database/database.inc(1197): DatabaseConnection_pgsql->query('UPDATE {aggrega...', Array, Array)\n#1 /var/www/projects/drupal/drupal-7.x-dev/modules/aggregator/aggregator.module(639): db_query('UPDATE {aggrega...', 'http://192.168....', 1223484545, 'htt in /var/www/projects/drupal/drupal-7.x-dev/includes/database/pgsql/database.inc on line 72