If you don&#39;t want to `SELECT SLEEP(1);`, you can also `DO SLEEP(1);`  It&#39;s useful for those situations in procedures where you don&#39;t want to see output.

e.g.

    SELECT ...
    DO SLEEP(5);
    SELECT ...

    SELECT ...
    SELECT SLEEP(5);
    SELECT ...

But what are you using this for? Are you trying to circumvent/reinvent mutexes or transactions?

Is there a difference between Crawling and Web-scraping?

If there&#39;s a difference, what&#39;s the best method to use in order to collect some web data to supply a database for later use in a customised search engine?


What is the difference between web-crawling and web-scraping?

Recently, I came across an issue where a CGI application is not responding. Symptom is Firefox displaying:

&gt; Transferring data from localhost...

But the thing is I cannot see any traffic from Firebug&#39;s Net panel, and the browser just stays on the same stage forever.

I am thinking about the ways to debug this application but I cannot see the source code or any of its compiled Java/C++ components, therefore I reckon a HTTP network level of diagnostics is a good start.

I have little experience in Fiddler and Wireshark, just wondering will they get better feedback/statistics in the HTTP network level? I&#39;ve heard Wireshark is advanced but could possibly introduce a large volume of traffic so system admins don&#39;t like it very much. At this time I think Firebug doesn&#39;t really show me enough information.

I need to collect information so that I can then forward to client as proof.

Wireshark vs Firebug vs Fiddler - pros and cons?

In relation to [my other question][1] today I am wondering how to use [MySQL&#39;s `SLEEP(duration)`](http://dev.mysql.com/doc/refman/5.6/en/miscellaneous-functions.html#function_sleep) correctly.

From what I gathered reading MySQL Dev forums and very vague description in MySQL Docs I can&#39;t use it this way:

    SELECT ...
    SLEEP(1); /* wait for a second before another SELECT */
    SELECT ...

So what is it good for then?


  [1]: https://stackoverflow.com/questions/4284162/calling-stored-procedure-sequentially-from-sql-file-and-php-fails-differently

How and when to use SLEEP() correctly in MySQL?

In relation to <a href="https://stackoverflow.com/questions/4284162/calling-stored-procedure-sequentially-from-sql-file-and-php-fails-differently" target="_blank" rel="noopener noreferrer">my other question</a> today I am wondering how to use <a href="http://dev.mysql.com/doc/refman/5.6/en/miscellaneous-functions.html#function_sleep" target="_blank" rel="noopener noreferrer">MySQL's <code>SLEEP(duration)</code></a> correctly.
From what I gathered reading MySQL Dev forums and very vague description in MySQL Docs I can't use it this way:
<pre><code class="hljs language-scss">SELECT ...
SLEEP(1); /* wait for a second before another SELECT */
SELECT ...
</code></pre>
So what is it good for then?

I&#39;m looking for the best way to check and see if any results were returned in a query. I feel like I write this part of code a lot and sometimes I get errors, and sometimes I don&#39;t.

For example, I run this query to check if a username exists before inserting a new one into the database.

    $result = mysql_query(&quot;SELECT * FROM ...&quot;);

Then I want to check and see if any results were returned. Here is one way I do it:

    if (!$result) { PERFORM ACTION }

If the first way doesn&#39;t work, then sometimes this will:

    if (mysql_num_rows($result)==0) { PERFORM ACTION }

Then I even saw that I could do it this way the other day:

    list($total) = mysql_fetch_row($result);
    if ($total==0) { PERFORM ACTION }


What is the best way to do this?

Best way to check if mysql_query returned any results?

I have a logging table that will contain millions of writes for statistical reasons. All the columns are int foreign keys. I am also going to add a timestamp column for each row. Given that DATETIME takes 8bits - I will be using `int(10) unsigned` to cut the storage space (and index on that column) in half. 

However, I&#39;m wondering when this column would no longer work. At 3:14:07AM on 19th January 2038 the value 9,999,999,999 will be a problem for UNIX timestamps - but an unsigned int in MySQL only holds up to 4,294,967,295 and the timestamp 4294967295 is showing an invalid number in my PHP application.

**So what does this mean? Is the end of the storing int timestamps in MySQL going to be sometime in 2021 since it can&#39;t make it all the way to 9999999999?**

**Answer:** 

 1. 2147483647 is 2038 (not 9999999999) so there is no problem. 
 2. `unsigned` isn&#39;t needed since 2147483647 fits fine in a signed MySQL int.

How should unix timestamps be stored in int columns?

What is the location of mysql client `.my.cnf` using XAMPP in Windows?

**Clarification**: This file does not exist by default, so when you create it, where should you place it, in order for the command line client to read it automatically?

What is the location of mysql client &quot;.my.cnf&quot; in XAMPP for Windows?

I need to export a mysql table, but it has like 5gb of entries, so I only want the structure. I am trying to do it from a simple php doing a sql query, how can I do that?

How to dump mysql table structure without data with a SQL query?

I am using Fedora 14 and I have MySQL and MySQL server 5.1.42 installed and running.
Now I tried to do this as root user:

    gem install mysql

But I get this error:

    Building native extensions.  This could take a while...
    ERROR:  Error installing mysql:
        ERROR: Failed to build gem native extension.

    /usr/bin/ruby extconf.rb
    mkmf.rb can&#39;t find header files for ruby at /usr/lib/ruby/ruby.h


    Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1 for inspection.
    Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api/gem_make.out

What&#39;s wrong here? In installed ruby 1.8.7. and the latest rubygems 1.3.7.


gem install: Failed to build gem native extension (can&#39;t find header files)

What is the use of `tim.tv_sec` and `tim.tv_nsec` in the following?

How can I sleep execution for `500000` microseconds?

    #include &lt;stdio.h&gt;
    #include &lt;time.h&gt;
 
    int main()
    {
       struct timespec tim, tim2;
       tim.tv_sec = 1;
       tim.tv_nsec = 500;
 
       if(nanosleep(&amp;tim , &amp;tim2) &lt; 0 )   
       {
          printf(&quot;Nano sleep system call failed \n&quot;);
          return -1;
       }
 
       printf(&quot;Nano sleep successfull \n&quot;);
 
       return 0;
    }

How to use nanosleep() in C? What are `tim.tv_sec` and `tim.tv_nsec`?

Is there a JavaScript function that simulates the operation of the `sleep` function in PHP — a function that pauses code execution for x milliseconds, and then resumes where it left off?

I found some things here on Stack Overflow, but nothing useful.

Is there a Sleep/Pause/Wait function in JavaScript?

I often see it mentioned that `Thread.Sleep();` should not be used, but I can&#39;t understand why this is so. If `Thread.Sleep();` can cause trouble, are there any alternative solutions with the same result that would be safe?

eg.

    while(true)
    {
        doSomework();
        i++;
        Thread.Sleep(5000);
    }

another one is:

    while (true)
    {
        string[] images = Directory.GetFiles(@&quot;C:\Dir&quot;, &quot;*.png&quot;);
    
        foreach (string image in images)
        {
            this.Invoke(() =&gt; this.Enabled = true);
            pictureBox1.Image = new Bitmap(image);
            Thread.Sleep(1000);
        }
    }

Why is Thread.Sleep so harmful

If I&#39;m going to have a call to have a Java Thread go to sleep, is there a reason to prefer one of these forms over the other?

    Thread.sleep(x)

or

    TimeUnit.SECONDS.sleep(y)



Thread.sleep vs. TimeUnit.SECONDS.sleep

I&#39;ve been using the `input` function as a way to pause my scripts:

    print(&quot;something&quot;)
    wait = input(&quot;Press Enter to continue.&quot;)
    print(&quot;something&quot;)

Is there a formal way to do this?


Content Type	Original Author	Original Content on Stackoverflow
Question	Michal M	View Question on Stackoverflow
Solution 1 - Mysql	Uncle Iroh	View Answer on Stackoverflow
Solution 2 - Mysql	Konerak	View Answer on Stackoverflow

How and when to use SLEEP() correctly in MySQL?

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Wireshark vs Firebug vs Fiddler - pros and cons?

What is the difference between web-crawling and web-scraping?

Attributions