Entry Processes Explained
What an Entry Process Is
Entry processes are the running copies of scripts, such as PHP pages, that a server starts to answer a request and stops once the response is sent. Hosting plans set a ceiling on how many entry processes an account can have running at the same moment.
Each request for a dynamic page can start an entry process. Static files such as images and plain HTML usually do not, because the web server can return them without running a script. Hosts also limit total processes, which include background jobs, scheduled tasks and other programs that run under the account. That is a separate count from entry processes. Shared hosting, where these limits are most common, is described in what is shared hosting.
Visitors, Requests and Concurrent Processes
Entry processes are not the same as visitors. One visitor can trigger several requests, for example a page plus background calls, form submissions or a checkout script. A site with many visitors may need only a few processes at once if each page finishes quickly.
The number of simultaneous processes depends on two things: how many script requests arrive each second, and how long each one takes. A rough rule is that concurrent processes equal requests per second multiplied by the average duration in seconds. For example, 10 script requests per second, each taking half a second, need about 5 entry processes at once. If each request takes two seconds instead, the same traffic needs about 20.
A Busy Moment on a Shared Plan
Consider a small online shop on a shared plan with a limit of 20 entry processes, a figure used here only as an example. Ordinary browsing stays well inside the limit, because most product pages respond quickly. During a sale, search requests and a slow checkout script take longer, and the number of requests rises at the same time. Once the simultaneous total passes the limit, further requests wait or fail, depending on the host. Visitors see slow pages and errors even though average traffic has not changed much.
Frequently asked questions
What happens when an account reaches its entry process limit?
New requests that need a script must wait for a free slot or are rejected, depending on the host's setup. Visitors may see slow pages, timeouts or a resource-limit error such as the one explained in the 508 resource limit error. Pages that do not run scripts, such as static images, are usually unaffected.
Are entry processes the same as concurrent visitors?
No. A concurrent visitor is a person on the site at the same moment, while an entry process is a script running on the server. One visitor can use several processes, and many visitors can share a few if pages respond quickly. The ratio depends on how heavy each page is and how long it takes to run.
Can I raise my entry process limit?
Usually by moving to a plan with a higher limit, or by reducing how many scripts each page needs. Some hosts offer higher tiers or dedicated resources for busy sites. The right step depends on what is using the processes, which often needs a review of the site's code and add-ons. The plan's resource limits show what each tier allows.