MySQL: Fix Error 2013 - Lost connection to MySQL server during query

Case: You have successfully connected to a MySQL/MariaDB database. But when trying to import a large SQL file, an error occurred.

Error Code: 2013. Lost connection to MySQL server during query

Reason:

- Timeout due to slow connection or too much data (Not the server's fault)

- Memory allocated is not enough: the data fields are too large ....

Quick fix:

Increase memory for Mysql package.

Find config file

Eg:

Xampp Windows: C:\xampp\mysql\bin\my.ini

Linux: /etc/my.cnf

Edit file my.ini (my.cnf), find [mysqld] block, to change max_allowed_packet to a larger value (16, 32, or 128 M)

Eg:

[mysqld]
.....
max_allowed_packet=128M

Then restart MySQL

*Note: 

- If max_allowed_packet is not found, you can add it to your [mysqld] block yourself.

- Increasing memory capacity may affect the stability of MySQL server. So you can freely change it on your local computer, but if you are on the product server, please consider carefully. Another solution to importing large mysql files on the server is to use the command line.

Done ! Solved !

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[PHP] Laravel Exception: Malformed UTF-8 characters, possibly incorrectly encoded

This error can be caused from many laravel modules such as Datatables, Json Output, Monolog ... So this is a very difficult error to analyze and fix. In this article we try to find some way to fix that bug in laravel (in the common cases).

Why did you get this error? and how to fix it?

* Case 1: In case of failure due to wrong configuration of database connection

The most common is when you connect to a second database. Developers often have a configuration that lacks the "charset" and "collation" parameters, causing the error as you see it:

Exception Message:↵↵Malformed UTF-8 characters, possibly incorrectly encoded

To fix it please configure the connection parameters are complete.

Eg:

'mysql' => array(
            'driver'    => 'mysql',
            'host'      => 'localhost',
            'database'  => 'database_name_1',
            'username'  => 'user_1',
            'password'  => 'password_1'
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
	    ....
 ),
/*mysql2 if you use two database*/
'mysql2' => array(
            'driver'    => 'mysql',
            'host'      => 'hostForDB2',
            'database'  => 'database_name_2',
            'username'  => 'user_2',
            'password'  => 'password_2'
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
	    ...
),

* Case 2: Regex Error - Caused by some regex function in route, url validate ....

PREG_BAD_UTF8_ERROR 'Malformed UTF-8 characters, possibly incorrectly encoded'

*Case 3: JSON Encode, Json output error - Caused by Monolog, Datatables Logs..

To Fix Case 2 & 3 you can try converting the input to utf-8, or remove non-utf-8 characters.

Eg1: Function to auto convert any string to utf-8 encoding

$newString = mb_convert_encoding($inputString, "UTF-8", "auto");

Eg2: fix utf-8 encoding for Datatables column

$datatable->editColumn('title', function(Post $node) {
            return mb_convert_encoding($node->title,"UTF-8", "auto");
        });

Done ! For any other questions you can leave them in the comment section at the end of this article. Thank you.

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MySQL: Fix Error 1071 "Specified key was too long"

MySQL/MariaDB Error 1071 when try to import SQL File:

#1071 - Specified key was too long; max key length is 767 bytes

Sometime error is "max key length is 1000 bytes"

Reason:

From MySQL 5.6 and MariaDB 10.2.2 InnoDB File Format default is Barracudar. Barracudar is newer file type ,support many new format types (DYNAMIC and COMPRESSED). But in older version of MySQL or MariaDB default InnoDB File Format is still Antelope. So if you want to import a database using Barracudar(exported from newer version), you also need to change the current file format to Barracudar.

Solved:

To do that, run the following command in the Mysql command line (Root account is required):

SET GLOBAL innodb_file_format = Barracuda;
SET GLOBAL innodb_file_per_table = on;
SET GLOBAL innodb_default_row_format = dynamic;
SET GLOBAL innodb_large_prefix = 1;
SET GLOBAL innodb_file_format_max = Barracuda;
FLUSH PRIVILEGES;

Done ! The problem has been solved, you can try imoport SQL file again.

Tip: You can run Mysql command line from linux terminal or run Query in Navicat, PHPMyadmin ....

mysql -h localhost -u root -p

Refer: https://dev.mysql.com/doc/refman/5.6/en/innodb-file-format-enabling.html

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Git: How to fix Error Pulling is not possible because you have unmerged files

If you try to pull new code while some local files have been changed without commit, you will get this error.

Error Pulling is not possible because you have unmerged files.

or

Error: Your local changes to the following files would be overwritten by merge

To fix it you have 2 options:

* Method 1: Commit the changes, then pull the new code

- Add new files if available

git add filename1.xyz folder/filename2.xyz  

or (add all new file)

git add -A    

- Commit new changes

git commit -m "Add new file or something need to noted"

* Method 2: Remove all local changes to update new code

(We often encounter this situation on the server)

To do so, run the following command:

git reset --hard origin/master

- note: 'master' is the name of the branch you want to update new code from that.

Done ! Now we can update new code by git pull command.

git pull

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MongoDB: Error Unsupported mechanism SCRAM-SHA-256

Studio 3T Fix Error 2 "Unsupported mechanism SCRAM-SHA-256" when try to connect to server.

Cause: 
MongoDB only supports SCRAM-SHA-256 for authenticating users with passwords from MongoDB version 4.0. So if you encounter this error, you can try to switch back to the SCRAM-SHA-1 method.

More about MongoDB SCRAM supports :
MongoDB >= 4.0 Support SCRAM-SHA-1 and SCRAM-SHA-256
MongoDB 3.x Support only MONGODB-CR and SCRAM-SHA-1
MongoDB <3.0 Support only MONGODB-CR

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Composer: How to fix error "Fork failed errors" in Linux server

In many cases we encounter lack of memory errors when running "composer install" or "composer update" command to update packages in our PHP project.
Some of the error messages you may receive:

• - proc_open(): fork failed errors - Cannot allocate memory
• - exception is caused by a lack of memory
• - Killed

The cause of all these errors is because our server does not have enough RAM to allocate to Composer. Increasing packages in the project, the larger the size, so this error is also becoming more and more common. To fix them you can increase the server's physical RAM but the cost will be quite expensive.

There is another solution simpler and completely free to fix Composer memory error. That is we can enable swap space for the server. This is quite easy to implement and will thoroughly fix the error we encounter. For each operating system, there will be different ways to initialize swap partitions. You can refer to one of the instructions below:

Enable Swap to fix Composer memory error for Centos, Ubuntu ...:

Step 1: Create a new Swap file (1GB to 3Gb)

sudo fallocate -l 3G /swapfile

Step 2: Add Write permission for Swap file

sudo chmod 600 /swapfile

* If your server is running under SELinux, after chmod command you must run the following command

sudo chcon -t swapfile_t /swapfile 

Step 3: set up a Linux swap area

sudo mkswap /swapfile

Step 4: Active Swap for server

sudo swapon /swapfile

opening the "/etc/fstab" file

vi /etc/fstab

then add the following line at end of file.

/swapfile swap swap defaults 0 0

Done ! If there are no errors, you have successfully enabled the swap for your server. You can try checking the swap partition with one of the following commands:

sudo swapon --show

or

top

or

sudo free -h

Now it's time to try running the composer commands again. Hopefully the bug has been fixed. Good luck.

*Note:
- /swapfile  - is file name for swap file, you can use another name or put it in another folder.
- In addition to using swap files, you can also try to use swap partitions.
- Some problems with PHP modules can also cause errors because Composer runs on PHP

*Refer: https://getcomposer.org/doc/articles/troubleshooting.md

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[zero-exception] The announcement of Website domain name changed

Dear friends,
Today we officially announce that the website domain name has been changed.

Domain name https://zero-exception.blogspost.com will now be changed to https://www.codesiri.com
All previous data and articles will be reserved.

This change aims to orient the development of website expansion in a more professional way. Hopefully, in the coming time, the website will have more useful articles for you.

Sincerely thank you !

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Wordpress: Change the title of any custom page dynamically

Sometime we want to custom the title for some page eg: 404, contact, search .... It is very simple, follow these instructions.

in file "your_theme/function.php" add the following code at the end.

function setTitle($title) {
    add_filter( 'wp_title', function() use ($title) {return $title;}, 10000 );
}

Done ! From now on, which page should be customized so that you just call the function like this:

setTitle('Hello, this is my custom title');

It does not affect the pages you do not use. Have fun!

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Yii2: PHP Warning - Unable to allocate memory for pool

Yii2 error:

PHP Warning – yii\base\ErrorException

include(): Unable to allocate memory for pool.

* Reason : You have not allocated enough memory for APC cache (file cache or opcode cache)

* Solution 1: Disable APC, If you do not need it (apc.enabled=0)
* Solution 2: Increased memory for APC (apc.shm_size="64")

To do one of the two. Find php.ini or apc.ini on your server. If you do not have admin rights to the server try to use htacess file: php_flag display_errors on

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Yii2: Get raw SQL Query from an Activerecord or a query builder

This tutorial show you how to dump the Sql Query from an Activerecord and more.
It can help us to debug Sql query in some case when yii debug is not work.

Example:

$listBooks = Books::find()->where('author=2')->all();

To get raw SQL query with all parameters included try:

$query = Books::find()->where('author=2');
echo $query->createCommand()->sql;
echo $query->createCommand()->getRawSql();

It not only works with Activerecord .

Refer : http://chris-backhouse.com/Yii2-Output-the-SQL-from-a-query-builder/1027

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