id summary reporter owner description type status priority milestone component version severity resolution keywords cc focuses 18239 wp_ob_end_flush_all() hangs the output buffering, during plugin update/install mamborambo "Symptom: During plugin update process, the screen displays ""Downloading {plugin}"" then appears to hang. System: Apache2 on LinuxMint-11 I traced the fault to the following function: send_message() in /wp-admin/includes/misc.php this function writes out the message, then tries to flush the buffers by calling wp_ob_end_flush_all() the mechanism of the ob_flush is to repeatedly call ob_end_flush until there is no more levels. On the default configuration of LinuxMint / Debian, zlib.output_compression is ON, and this interferes with ob_end_flush Based on notes from php.net, ob flushing is not necessary. SOLUTION: 1) Either change php.ini to set zlib.output_compression to OFF, or 2) shortcircuit the wp_ob_end_flush_all() by adding an immediate return to the first line. RECOMMENDATION: In future versions of WordPress, the interaction between ob and zlib should be studied carefully to derive the most universal solution. " defect (bug) closed normal Upgrade/Install 3.2.1 minor duplicate output hangs