在PHP中设置一段时间的睡眠时间

Question

hey guys I'm trying to write an update script in which i need to set sleep time for each row and then continue the process

as long as the process is so giant and cannot be done at once ( switching Latin-1 Charset into UTF-8 ) then i need sleep time after each row is converted

this is a usual and working code to convert into utf-8 but the sleep time doesn't work and again its doing it all at once .

 ob_implicit_flush();

 $result = $db->sql_query("SHOW TABLES");
 while ($row = $db->sql_fetchrow($result)) {
  $db->sql_query("ALTER TABLE $row[0] COLLATE $collation");
  $result1 = $db->sql_query("SHOW COLUMNS FROM $row[0]");
  while ($row1 = $db->sql_fetchrow($result1)) {
   if (preg_match('~char|text|enum|set~', $row1["Type"])) {
    $db->sql_query("ALTER TABLE $row[0] MODIFY $row1[Field] $row1[Type] CHARACTER SET binary");
    $db->sql_query("ALTER TABLE $row[0] MODIFY $row1[Field] $row1[Type] COLLATE $collation" . ($row1["Null"] ? "" : " NOT NULL") . ($row1["Default"] && $row1["Default"] != "NULL" ? " DEFAULT '$row1[Default]'" : ""));
   }
   echo"sleep for 2 seconds ....<br> $row[0] is already converted.";  
 // wait for 2 seconds 
   usleep(2000000);
   // back!
   echo date('h:i:s') . "\n";

  }

 }

Answer 1

Have you tried simple sleep command

sleep(2);

http://php.net/manual/en/function.sleep.php

Answer 2

It seems that you are 'sleeping' between every table not between every column update - is that the way you wanted it to be? Anyway if data is big 2 seconds may be too low time

There was also a bug in Windows PHP where you had to set infinite time limit or sleep would make high CPU usage.

set_time_limit(0);

Answer 3

Unlike Simon, I can see that there is some merit in leaving gaps between the updates, however Why do you update each column in a seperate operation? It'll be a lot faster if you change them all at once.

Answer 4

I do not see the effort of your sleep. What are you waiting for during those two seconds? The script can not do an other job while its sleeping.