Identify Deadlocks Using Graphical Deadlock Chain Event in SQL Server Profiler

In SQL Server, a deadlock occurs when two or more processes attempt to acquire exclusive locks on resources in such a way that a circular chain is formed, where each process is waiting for another process to release the lock it holds. Deadlocks can be resolved by having one of the processes involved in the deadlock abort, so that its locks are released and the other process can continue.

When a deadlock occurs, SQL Server automatically detects it and ends one of the user processes (the "victim"), allowing the other process to complete. This event is then recorded in the SQL Server error log.

To identify which process was aborted during a deadlock, you can use the Graphical Deadlock Chain Event in SQL Server Profiler. This event will show you the processes involved in the deadlock, as well as which process was aborted.

To use the Graphical Deadlock Chain Event in SQL Server Profiler:

1. Start SQL Server Profiler and connect to the instance of SQL Server where the deadlock occurred.

2. Create a new trace or use an existing trace that includes the events you want to capture. For more information, see designing a Trace (SQL Server Profiler).

3. In the Events Selection tab, select the checkbox for the Graphical Deadlock Chain event under the Locks category.

4. Run the trace.

When a deadlock occurs, the Graphical Deadlock Chain event will be recorded in the trace. This event will show you the processes involved in the deadlock, as well as which process was aborted.

5. To view the details of the event, double-click it in the trace results.

6. In the Event Properties dialog box, click the Deadlock tab.

7. The details of the deadlock will be displayed in a graphical format, showing which processes were involved and which process was aborted.

8. To save the deadlock information to a file, click Save As and choose a location for the file.

When troubleshooting deadlocks, it is important to remember that SQL Server automatically detects and resolves them. In most cases, there is no need to take any further action. However, if you are seeing frequent deadlocks, or if they are causing performance problems, you may need to investigate further and take steps to prevent them from occurring.

For more information, see Deadlocks (SQL Server).

When a deadlock occurs, SQL Server automatically detects it and ends one of the user processes (the "victim"), allowing the other process to complete. This event is then recorded in the SQL Server error log.

To identify which process was aborted during a deadlock, you can use the Graphical Deadlock Chain Event in SQL Server Profiler. This event will show you the processes involved in the deadlock, as well as which process was aborted.

To use the Graphical Deadlock Chain Event in SQL Server Profiler:

1. Start SQL Server Profiler and connect to the instance of SQL Server where the deadlock occurred.

2. Create a new trace or use an existing trace that includes the events you want to capture. For more information, see designing a Trace (SQL Server Profiler).

3. In the Events Selection tab, select the checkbox for the Graphical Deadlock Chain event under the Locks category.

4. Run the trace.

When a deadlock occurs, the Graphical Deadlock Chain event will be recorded in the trace. This event will show you the processes involved in the deadlock, as well as which process was aborted.

5. To view the details of the event, double-click it in the trace results.

6. In the Event Properties dialog box, click the Deadlock tab.

7. The details of the deadlock will be displayed in a graphical format, showing which processes were involved and which process was aborted.

8. To save the deadlock information to a file, click Save As and choose a location for the file.

Conclusion:

When troubleshooting deadlocks, it is important to remember that SQL Server automatically detects and resolves them. In most cases, there is no need to take any further action. However, if you are seeing frequent deadlocks, or if they are causing performance problems, you may need to investigate further and take steps to prevent them from occurring.

Drag And Drop Multiple File Upload with Progress Bar using JavaScript

Hi Guys, In this tutorial, You can learn How to make Drag and Drop File Upload Feature with progress bar by using Pure Vanilla JavaScript with HTML CSS and PHP. In previous tutorial, we have already shared tutorial on how to Upload multiple file with progress bar using JavaScript with PHP by select multiple file from file tag but under this post, we will show you have can we upload multiple file by drag and drop feature with progress bar using JavaScript in PHP.

Do you know What is Drag and Drop File Upload, so if you not know then Drag and Drop file uploading means, we can directly upload file by drag and drop. By using Drag & Drop file upload feature, it has provide interfaces which will permits our web application to drag and drop files on the web page. We have seen this types of functionality on many websites on internet. So for make drag and drop features, there are many JavaScript libraries are available and by using that library we can build our own drag and drop multiple file upload feature by writing few lines of code but under this tutorial we will make drag and drop multiple file upload features by using pure JavaScript without using any in build library.

View Demo

Under this Drag and Drop Multiple File Upload tutorial, there will be a drag area on web page, so when we have drag any file over this drag area then the border of that drag area will be change to solid and it will display copy file here text under drag area. So when we have drop multiple file under this drag area, then it will start uploading file one by one and it will display multiple file upload process in progress bar.

In this tutorial, we have use HTML, CSS JavaScript and Bootstrap 5 Style sheet library at client-side that means drag area we will create using HTML and CSS, files data get from drag and drop area using JavaScript, progress bar will be create using Bootstrap and at server side we have use PHP Script for upload multiple file on to the server. Below you can find source code of Drag and Drop Upload Multiple files with progress bar using JavaScript in PHP.

Source Code

index.html

<!doctype html>
<html lang="en">
    <head>
        <!-- Required meta tags -->
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">

        <!-- Bootstrap CSS -->
        <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC" crossorigin="anonymous">

        <title>Drag & Drop Upload Multiple File with Progress Bar using JavaScript in PHP</title>
    </head>
    <body>

        <div class="container">
            <h1 class="mt-5 mb-5 text-center text-primary"><b>Drag & Drop Upload Multiple File with Progress Bar using JavaScript in PHP</b></h1>

            <div class="card">
                <div class="card-header">Drag & Drop File Here</div>
                <div class="card-body">
                    <div class="row">
                        <div class="col-md-3">&nbsp;</div>
                        <div class="col-md-6">
                            <div id="drag_drop">Drag & Drop File Here</div>
                        </div>
                        <div class="col-md-3">&nbsp;</div>
                    </div>
                </div>
            </div>
            <br />
            <div class="progress" id="progress_bar" style="display:none; height:50px;">
                <div class="progress-bar bg-success" id="progress_bar_process" role="progressbar" style="width:0%; height:50px;">0%

                </div>
            </div>
            <div id="uploaded_image" class="row mt-5"></div>
        </div>
    </body>
</html>

<style>

#drag_drop{
    background-color : #f9f9f9;
    border : #ccc 4px dashed;
    line-height : 250px;
    padding : 12px;
    font-size : 24px;
    text-align : center;
}

</style>

<script>

function _(element)
{
    return document.getElementById(element);
}

_('drag_drop').ondragover = function(event)
{
    this.style.borderColor = '#333';
    return false;
}

_('drag_drop').ondragleave = function(event)
{
    this.style.borderColor = '#ccc';
    return false;
}


_('drag_drop').ondrop = function(event)
{
    event.preventDefault();

    var form_data  = new FormData();

    var image_number = 1;

    var error = '';

    var drop_files = event.dataTransfer.files;

    for(var count = 0; count < drop_files.length; count++)
    {
        if(!['image/jpeg', 'image/png', 'video/mp4'].includes(drop_files[count].type))
        {
            error += '<div class="alert alert-danger"><b>'+image_number+'</b> Selected File must be .jpg or .png Only.</div>';
        }
        else
        {
            form_data.append("images[]", drop_files[count]);
        }

        image_number++;
    }

    if(error != '')
    {
        _('uploaded_image').innerHTML = error;
        _('drag_drop').style.borderColor = '#ccc';
    }
    else
    {
        _('progress_bar').style.display = 'block';

        var ajax_request = new XMLHttpRequest();

        ajax_request.open("post", "upload.php");

        ajax_request.upload.addEventListener('progress', function(event){

            var percent_completed = Math.round((event.loaded / event.total) * 100);

            _('progress_bar_process').style.width = percent_completed + '%';

            _('progress_bar_process').innerHTML = percent_completed + '% completed';

        });

        ajax_request.addEventListener('load', function(event){

            _('uploaded_image').innerHTML = '<div class="alert alert-success">Files Uploaded Successfully</div>';

            _('drag_drop').style.borderColor = '#ccc';

        });

        ajax_request.send(form_data);
    }
}

</script>

upload.php

<?php

//upload.php

if(isset($_FILES['images']))
{
	for($count = 0; $count < count($_FILES['images']['name']); $count++)
	{
		$extension = pathinfo($_FILES['images']['name'][$count], PATHINFO_EXTENSION);

		$new_name = uniqid() . '.' . $extension;

		move_uploaded_file($_FILES['images']['tmp_name'][$count], 'images/' . $new_name);
	}

	echo 'success';
}

?>

View Demo