Fatal error: Allowed memory size, boost.module on line 2015

hmmm looking at the code on those lines, it will be hard to fix. Boost is trying to use about a megabyte of ram for array modifications according to the errors. The link you posted (XML-RPC) has nothing to do with the code in question (array manipulation). What I could do is not use batch processing; it would be a lot slower but it won't use up as much ram. I would look elsewhere, because something is using up a bunch of your ram & boost appears to be the straw that broke the camels back.

function boost_cache_kill($files, $force_flush = FALSE) {
  $hashes = array();
  $count = 0;

  if (!$files) {
    return FALSE;
  }

  // If not ignoring file removal
  // AND site is multisite and cache path matches filename
  //  OR full base url matches filename
  if (variable_get('boost_ignore_flush', 0) < 3) {
    // Calc md5 hash and set base dir
    foreach ($files as $key => $file) {
      if (!is_string($file['filename'])) {
        if (BOOST_VERBOSE >= 5) {
          watchdog('boost', 'Error in boost_cache_kill() <br />String was not given for filename: !output', array('!output' => boost_print_r($file, TRUE, TRUE)));
        }
        continue;
      }
      if (empty($file['hash'])) {
        $files[$key]['hash'] = md5($file['filename']);
      }
      if (empty($file['base_dir'])) {
        $files[$key]['base_dir'] = BOOST_FILE_PATH;
      }
      $hashes[] = $files[$key]['hash']; //LINE 2014
      if (stristr($files[$key]['filename'], BOOST_ROOT_CACHE_DIR) == FALSE) { // LINE 2015
        unset($files[$key]);
      }
    }
    // Expire entries from Database
    if (count($hashes)) {
      if ($force_flush || !BOOST_EXPIRE_NO_FLUSH) {
        boost_db_multi_update_set('boost_cache', 'expire', '%d', 0, 'hash', "'%s'", $hashes);
      }
      else {
        boost_db_multi_update_set('boost_cache', 'expire', '%d', 434966400, 'hash', "'%s'", $hashes);
        $count = db_affected_rows();
      }
    }
    // Kill Files from filesystem
    if ($force_flush || !BOOST_EXPIRE_NO_FLUSH) {
      foreach ($files as $file) {
        $filenames = boost_get_all_filenames($file['filename'], $file['base_dir']);
        foreach ($filenames as $key => $values) {
          foreach ($values as $num => $filename) {
            if (file_exists($filename)) {
              @unlink($filename);
              if ($key == 'normal' && $num == 0) {
                $count++;
              }
            }
          }
        }
      }
    }
  }
  return $count;
}

function boost_db_multi_update_set($table, $set_field, $set_placeholders, $set_value, $where_field, $where_placeholder, $data) {
  // Get the number of rows that will be inserted
  $rows = count($data);
  // Create what goes in the IN ()
  $in = $where_placeholder;
  // Add the rest of the place holders
  for ($i = 1; $i < $rows; $i++) {
    $in .= ', ' . $where_placeholder;
  }
  // Build the query
  $query = "UPDATE {" . $table . "} SET $set_field = $set_placeholders WHERE $where_field IN ($in)";
  // Add the set value to the top of the array
  array_unshift($data, $set_value); // LINE 3784
  // Run the query
  return db_query($query, $data);
}

well it keeps choking on the boost_cache_kill function, trying to allocate small amounts of memory from what I can tell. What changed?

Like I stated before, something changed on your site and is eating up all the ram. Boost works with millions of nodes so I'm tempted to say look somewhere else for the issue...

Best bet is to setup the site local & run xdebug on it.
Guessing your using xampp so this guide should be helpful
http://unitstep.net/blog/2009/01/26/getting-xdebug-to-work-with-apachexa...

Think this is similar / related to

http://drupal.org/node/936422#comment-3633892

created an issue with views #988680: Memory leak with $view->pre_execute() & $view->attach_displays() and looking for a work around atm.

committed this change

Hello Mikey

I got this error after applying the patch.

patch -b < boost-882568.patch
patching file boost.module
Hunk #1 FAILED at 1327.
1 out of 1 hunk FAILED -- saving rejects to file boost.module.rej

patch is for the dev version of boost; and if your running the latest dev, it already has it committed.