Start the profiler with 

    SET profiling = 1;

Then execute your Query. 

With

    SHOW PROFILES;

you see a list of queries the profiler has statistics for. And finally you choose which query to examine with

    SHOW PROFILE FOR QUERY 1;

or whatever number your query has.

What you get is a list where exactly how much time was spent during the query.

More info in the [manual.][1]


  [1]: http://dev.mysql.com/doc/refman/5.0/en/show-profiles.html

The accepted Answer is becoming invalid...

`SHOW PROFILE[S]` are **deprecated as of MySQL 5.6.7** and will be removed in a future MySQL release. Use the Performance Schema instead; see http://dev.mysql.com/doc/refman/5.6/en/performance-schema-query-profiling.html


I try to migrate to `GCM` and I have an issue with the `SENDER_ID` I need to provide. I use the demo project from google. In this project I need, if I understand this well, to provide a `SENDER_ID` to the application in the CommonUtilities.java file. 

The SENDER_ID I provided is the API key I registered on https://code.google.com/apis/console/ and has this form: `AIzaSyAxxxxxxx_xxxxxxxxxxxnoGZw` (total 40 chars).

Using this string as `SENDER_ID` I get on &quot;BroadcastReceiver mHandleMessageReceiver&quot; an error message: **From GCM: error (INVALID_SENDER).**.

_Where is the mistake? The string I provide is not the `SENDER_ID`?_

Thank you.


Android GCM SENDER_ID, how to get it?

I often use this piece of code in PHP

    $ordine[&#39;address&#39;] = implode(&#39;, &#39;, array_filter(array($cliente[&#39;cap&#39;], $cliente[&#39;citta&#39;], $cliente[&#39;provincia&#39;])));

It clears empty strings and join them with a &quot;,&quot;. If only one remains it doesn&#39;t add an extra unneeded comma. It doesn&#39;t add a comma at the end. If none remains it returns empty string.

Thus I can get one of the following results

    &quot;&quot;
    &quot;Street abc 14&quot;
    &quot;Street abc 14, 00168&quot;
    &quot;Street abc 14, 00168, Rome&quot;

What is the best Java implementation (less code) in Java **without having to add external libraries** (designing for Android)?





Java equivalent of PHP&#39;s implode(&#39;,&#39; , array_filter( array () ))

How can I measure the execution time of a query without measuring the time it spends waiting for a lock release etc? My only idea was to continuously measure same query and record the fastest time. 

Measuring actual MySQL query time

<p>How can I measure the execution time of a query without measuring the time it spends waiting for a lock release etc? My only idea was to continuously measure same query and record the fastest time.</p>


I know that this line of code will make the cell text-wrap:

    $objPHPExcel-&gt;getActiveSheet()-&gt;getStyle(&#39;D1&#39;)-&gt;getAlignment()-&gt;setWrapText(true);
&#39;D1&#39; being the chosen cell.

Instead of using this code for every cell I need wrapped, is there a way to make the entire Excel Worksheet automatically wrap everything?

Or is there a better practice technique to use for specified columns? 

PHPExcel and Text Wrapping

I want to import a sql file of approx 12 mb. But its causing problem while loading. Is there any way to upload it without splitting the sql file ?

How to import large sql file in phpmyadmin

I got the following error while trying to alter a column&#39;s data type and setting a new default value:

    ALTER TABLE foobar_data ALTER COLUMN col VARCHAR(255) NOT NULL SET DEFAULT &#39;{}&#39;;

&gt; ERROR 1064 (42000): You have an error in your SQL syntax; check the
&gt; manual that corresponds to your MySQL server version for the right
&gt; syntax to use near &#39;VARCHAR(255) NOT NULL SET DEFAULT &#39;{}&#39;&#39; at line 1

How to alter a column and change the default value?

I&#39;ve used the mysqli_stmt_bind_param function several times. However, if I separate variables that I&#39;m trying to protect against SQL injection I run into errors.

Here&#39;s some code sample:

    function insertRow( $db, $mysqli, $new_table, $Partner, $Merchant, $ips, $score, $category, $overall, $protocol )
    {
        $statement = $mysqli-&gt;prepare(&quot;INSERT INTO &quot; .$new_table . &quot; VALUES (?,?,?,?,?,?,?);&quot;);
        mysqli_stmt_bind_param( $statment, &#39;sssisss&#39;, $Partner, $Merchant, $ips, $score, $category, $overall, $protocol );
        $statement-&gt;execute();
    }

Is it possible to somehow replace the `.$new_table.` concatenation with another question mark statement, make another bind parameter statement, or add onto the existing one to protect against SQL injection?

Like this or some form of this:

    function insertRow( $db, $mysqli, $new_table, $Partner, $Merchant, $ips, $score, $category, $overall, $protocol )
    {    
        $statement = $mysqli-&gt;prepare(&quot;INSERT INTO (?) VALUES (?,?,?,?,?,?,?);&quot;);
        mysqli_stmt_bind_param( $statment, &#39;ssssisss&#39;, $new_table, $Partner, $Merchant, $ips, $score, $category, $overall, $protocol );
        $statement-&gt;execute();
    }




Can I parameterize the table name in a prepared statement?

I am trying to learn the best way to write queries. I also understand the importance of being consistent. Until now, I have randomly used single quotes, double quotes, and backticks without any real thought.

Example:

    $query = &#39;INSERT INTO table (id, col1, col2) VALUES (NULL, val1, val2)&#39;;

Also, in the above example, consider that `table`, `col1`, `val1`, etc. may be variables.

What is the standard for this? What do you do?

&lt;sub&gt;I&#39;ve been reading answers to similar questions on here for about 20 minutes, but it seems like there is no definitive answer to this question.&lt;/sub&gt;

When to use single quotes, double quotes, and backticks in MySQL

I&#39;m not sure if the following code can cause redundant calculations, or is it compiler-specific?

    for (int i = 0; i &lt; strlen(ss); ++i)
    {
        // blabla
    }

Will `strlen()` be calculated every time when `i` increases?

Will strlen be calculated multiple times if used in a loop condition?

After conducting some experiments on square matrices of different sizes, a pattern came up. Invariably, **transposing a matrix of size `2^n` is slower than transposing one of size `2^n+1`**. For small values of `n`, the difference is not major.

Big differences occur however over a value of 512. (at least for me)

*Disclaimer: I know the function doesn&#39;t actually transpose the matrix because of the double swap of elements, but it makes no difference.*

Follows the code:

    #define SAMPLES 1000
    #define MATSIZE 512

    #include &lt;time.h&gt;
    #include &lt;iostream&gt;
    int mat[MATSIZE][MATSIZE];
 
    void transpose()
    {
       for ( int i = 0 ; i &lt; MATSIZE ; i++ )
       for ( int j = 0 ; j &lt; MATSIZE ; j++ )
       {
           int aux = mat[i][j];
           mat[i][j] = mat[j][i];
           mat[j][i] = aux;
       }
    }
 
    int main()
    {
       //initialize matrix
       for ( int i = 0 ; i &lt; MATSIZE ; i++ )
       for ( int j = 0 ; j &lt; MATSIZE ; j++ )
           mat[i][j] = i+j;

       int t = clock();
       for ( int i = 0 ; i &lt; SAMPLES ; i++ )
           transpose();
       int elapsed = clock() - t;

       std::cout &lt;&lt; &quot;Average for a matrix of &quot; &lt;&lt; MATSIZE &lt;&lt; &quot;: &quot; &lt;&lt; elapsed / SAMPLES;
    }

Changing `MATSIZE` lets us alter the size (duh!). I posted two versions on ideone:

- **size 512** - average **2.46 ms** - http://ideone.com/1PV7m
- **size 513** - average **0.75  ms** - http://ideone.com/NShpo

In my environment (MSVS 2010, full optimizations), the difference is similar :

- **size 512** - average **2.19 ms** 
- **size 513** - average **0.57  ms**

**Why is this happening?**

Why is transposing a matrix of 512x512 much slower than transposing a matrix of 513x513?

I&#39;m using Eclipse PDT on a rather large PHP project and the IDE is almost unusable. It takes nearly 30 seconds to open a file, and other actions, like selecting a folder in the file explorer, editing some text, etc. are equally slow.

I followed various instructions to speed it up but nothing seems to work. This is my current `eclipse.ini` file. Any idea how I can improve it?

	-startup
	plugins/org.eclipse.equinox.launcher_1.3.0.v20120522-1813.jar
	--launcher.library
	plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.200.v20120522-1813
	-showsplash
	org.eclipse.platform
	--launcher.XXMaxPermSize
	256m
	--launcher.defaultAction
	openFile
	-vmargs
	-server
	-Dosgi.requiredJavaVersion=1.7
	-Xmn128m
	-Xms1024m
	-Xmx1024m
	-Xss2m
	-XX:PermSize=128m
	-XX:MaxPermSize=128m
	-XX:+UseParallelGC
	
System: Eclipse 4.2.0, Windows 7, 4 GB RAM

Very slow Eclipse 4.2, how to make it more responsive?

I have heard from various sources (though mostly from a colleague of mine), that compiling with an optimisation level of `-O3` in g++ is somehow &#39;dangerous&#39;, and should be avoided in general unless proven to be necessary.

Is this true, and if so, why? Should I just be sticking to `-O2`?

Is optimisation level -O3 dangerous in g++?

I&#39;m trying to write huge amounts of data onto my SSD(solid state drive). And by huge amounts I mean 80GB.

I browsed the web for solutions, but the best I came up with was this:

    #include &lt;fstream&gt;
    const unsigned long long size = 64ULL*1024ULL*1024ULL;
    unsigned long long a[size];
    int main()
    {
        std::fstream myfile;
        myfile = std::fstream(&quot;file.binary&quot;, std::ios::out | std::ios::binary);
        //Here would be some error handling
        for(int i = 0; i &lt; 32; ++i){
            //Some calculations to fill a[]
            myfile.write((char*)&amp;a,size*sizeof(unsigned long long));
        }
        myfile.close();
    }

Compiled with Visual Studio 2010 and full optimizations and run under Windows7 this program maxes out around 20MB/s. What really bothers me is that Windows can copy files from an other SSD to this SSD at somewhere between 150MB/s and 200MB/s. So at least 7 times faster. That&#39;s why I think I should be able to go faster.

Any ideas how I can speed up my writing?

Content Type	Original Author	Original Content on Stackoverflow
Question	Mikhail	View Question on Stackoverflow
Solution 1 - Mysql	fancyPants	View Answer on Stackoverflow
Solution 2 - Mysql	Rick James	View Answer on Stackoverflow

Measuring actual MySQL query time

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Java equivalent of PHP's implode(',' , array_filter( array () ))

Android GCM SENDER_ID, how to get it?

Attributions