Reviewer bug in research portal

When admin assign himself as reviewer, view_project.php hanged.
This is due to that
C:\Users\jiansen\Desktop\CAS\jiansen_dir\www_cesei0_mobile\research\projects\view_project.php
line49
   $reviewer = get_reviewer($_SESSION['member_id']);
call get_reviewers function in 
C:\Users\jiansen\Desktop\CAS\jiansen_dir\www_cesei0_mobile\research\_lib\projects\reviewer_tools.inc.php
get_reviewers function is very complicated to make system hanged.
Solution:
1. Reduce research database.
2.  CESEI PHP error log need to be cleaned often
C:\php5.3.1\error.log, around 9GB. Difficult to open and write.
3. Think about new algorithm to write function 
get_reviewers
Use  $start=microtime(true); $end=microtime(true); 
$end-start to get processing time in seconds in get_reviewers function.
or try
echo  date('h:i:s') . "\n";
to see time difference.
Find
  $sql = "SELECT subject_id,study_code,active,reminders FROM subjects WHERE subject_id IN(
               SELECT subject_id FROM review_slot_subjects WHERE review_slot_id
                  IN (SELECT review_slot_id FROM review_slots WHERE project_id=$pid AND review_slot_id
                     IN (SELECT review_slot_id FROM review_slot_reviewers WHERE member_id=$rid))) ORDER BY study_code";
      $result = mysql_query($sql, $db);
take about 2 minutes.
change the statement into two steps:
//step 1
$sql = "SELECT subject_id FROM review_slot_subjects WHERE review_slot_id
                  IN (SELECT review_slot_id FROM review_slots WHERE project_id=$pid AND review_slot_id
                     IN (SELECT review_slot_id FROM review_slot_reviewers WHERE member_id=$rid))";
        $result = mysql_query($sql, $db);
       $subject_id_array=array();
    while($row = mysql_fetch_assoc($result))  $subject_id_array[]=$row['subject_id'];
   //step 2
    $matches = implode(',',$subject_id_array);        
    $sql = "SELECT subject_id,study_code,active,reminders FROM subjects WHERE subject_id IN(
               $matches) ORDER BY study_code";
      $result = mysql_query($sql, $db);

The MySQl execution time is reduced to few seconds.