APMdigest asked industry experts – from analysts and consultants to the top vendors – to outline the most important factors that impact website response time. The third installment of the list, featuring factors 11–15, covers the back end.

Start with Part 1 of "20 Top Factors That Impact Website Response Time"

Start with Part 2 of "20 Top Factors That Impact Website Response Time"

11. THE BACK-END SERVER

From our perspective, back-end server responsiveness is the main factor to ensure a fast website response time.
Alon Girmonsky
Founder and CEO, BlazeMeter

Inadequate server resources: When the traffic to a website suddenly increases, the web server gets more requests than it can handle and fails to function efficiently. As a result, the website takes up additional server resources such as memory, disk space, bandwidth and processes, leading to a bottleneck on the server’s resources. If IT Ops don’t pay attention to the growing resource demands and plan capacity accordingly, this can lead to severe resource shortages resulting in poor-responding websites.
Arun Balachandran
Sr. Market Analyst, ManageEngine

Website response times are often tied to server performance, and when a site is slow to load, the underlying cause can be a server delay driven by network bandwidth issues such as BYOD. Because speed is a critical factor in keeping people productive with online apps, or engaged with your website, it’s imperative that organizations are proactive in monitoring servers, networks and applications to identify problems before your online end users are impacted.
Aaron Kelly
VP of Product Management, Ipswitch

While there are plethora of factors that can affect website performance, the top factor in my experience is the performance of its back-end calls. It does not matter if it is a RDBMS, an ERP system, a User directory or simply another application. If the back-end calls are slow, user experience will tank. Maybe the website is running out of database connections; maybe it is making excessive back-end calls; or maybe the back-end server is running out of hardware resources. Whatever the cause, slow back-end calls will eventually bring the website to its knees. Be sure to armor yourself with a modern APM tool to pinpoint the root cause of these slow calls.
Karun Subramanian
Application Support Expert, www.karunsubramanian.com

12. THE DATABASE

According to many reviews written by the IT Central Station community, the top factor that impacts website response time is slow database queries. Some of our reviewers recommend analyzing the queries that are executed, ensuring that they are using indexes correctly. In this way, the time spent in the database can be reduced, improving the response time.
Russell Rothstein
Founder and CEO, IT Central Station

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When users experience poor website response time, IT needs to dig deeper than the network or applications. When loading, a web page might not show any errors, but users could be waiting on key dynamic content like a bank balance or an order status. This issue is frequently not the web or application server, but the database that supports them. Bad SQL code and non-optimized databases account for as many as two-thirds of all such website performance issues. Optimize SQL queries to boost website performance so people can blame the network again.
Robert Anderson
Sr. Director of Product, Idera

One of the top factors that we've seen in our analysis of hundreds of applications is interactions with databases; either slow database queries or too many database queries being executed per web request. As companies analyze how their code spends it's time, it is essential to see how often queries are called and how long they take to run.
Matt Watson
Founder and CEO, Stackify

13. THIRD PARTY SERVICES

Third-party integrations such as SaaS vendor plugins can have a “creeping” impact on website performance. As you accumulate more functionality via third-party vendors, you have great functionality, but there is a performance hit. Each plug-in can run multiple queries which causes longer than optimal server side processing. By understanding the performance of queries supporting your website or web application, you can take action to optimize or combine queries for improved performance.
Michael Thompson
Director, Systems Management Product Marketing, SolarWinds

Third party vendors tend to be the biggest factor when it comes to delaying load times. The amount of requests a site has to make not only increases the time needed to load all of the elements, but also increases the chances for failure somewhere along the way. Furthermore, while reliance on third party infrastructure like DNS and CDNs can help expand the scope of your site’s user base, they also make it harder to detect isolated slowness or outages that may be localized to only a portion of your users. Without a comprehensive monitoring strategy of those third parties, you may not even know that you’re experience performance issues.
Drit Suljoti
Chief Product Officer, Catchpoint

On the client side it is counter-intuitive - when you cram sites full of “bells and whistles” to influence potential customers, problems can arise. This is because videos, pop-up chats, and pay later options are typically driven by third party applications or hosted on CDNs. Add-ons like these often create performance issues that are difficult to identify and diagnose without a robust digital performance strategy and technology that provides a comprehensive end-to-end view encapsulating 100% of every end-user experience. From a customer's perspective, it’s best to think about what a site doesn’t need - and how to simplify and streamline instead. A function that comes at the cost of performance does more harm than good.
David Jones
APM Evangelist, Dynatrace

14. THE NETWORK

For a modern website built using today’s coding and content best practices along with sufficient host resources, acceptable user response time is only as good as the underlying network. The main variable is throughput, which is the actual amount of data that can be delivered across a network at a given time. All things being equal, the fatter the pipe the better the web performance. Throughput takes into account variables that reduce a network’s theoretical maximum transfer rate (bandwidth) including underlying physical network status, network topology, number of users, and overall network integrity. These factors can negatively impact website response time. Having performance monitoring tools that can characterize these network attributes will enable organizations to achieve optimal website performance.
Brad Reinboldt
Solution Manager, Network Instruments/JDSU

Network delay for websites is the big issue. It is ultimately caused by a number of network related factors, not just bandwidth as many believe. So, website developers need to ensure they fully understand how well any site they create is going to be able to cope with the delays caused by a range of network conditions. This is going to involve conducting comprehensive pre-deployment testing in accurate replications of different network environments which is made possible, even easy, with network emulation.
Frank Puranik
Senior Technical Specialist, iTrinegy

15. VIRTUALIZATION

Over commitment of virtualized infrastructure is frequently the cause of “Performance Phantoms" that plague websites: intermittent response time spikes which have inconsistent reasons for delay. Developers chase the delay, attempting to optimize an ever-changing set of slow code identified by APM tools, yet the issue persists. In these cases the slow code is not the root cause, but rather a symptom of micro-pauses of the VM which occur when the hypervisor has a demand that exceeds available resources, so any code unlucky enough to be running during pauses gets equivalently slower. Mission critical websites running in cloud or virtualized environments should be provisioned with dedicated resources to ensure that other tenants can’t steal resources and impact website performance.
Jon C. Hodgson
Global Consulting Engineer, Riverbed

One of the most common and yet difficult things for any admin to accomplish is to trouble shoot end user “slow-time” issues. Slow-time negatively affects enterprise performance and end user productivity ten times more often than downtime and can originate from just about anywhere within the enterprise. Constrained virtual resources can be the root cause of slow-time, or it could just be a resulting symptom. The key to resolving this issue is getting to the root cause quickly before the problem spreads to other systems bringing productivity to a standstill. The use of a 100% web based performance management solution will enable IT administrators to have universal insight into the infrastructure and enable IT to take action anytime, from anywhere on any device. The benefit is total visibility across all layers and tiers of the enterprise. Having universal insight enables and empowers IT admins to enhance IT service performance, increase operational efficiency and ensure IT effectiveness.
Srinivas Ramanathan
CEO, eG Innovations

Read Part 4 of "20 Top Factors That Impact Website Response Time"