Title: Issue with Cache Preload Last modified: November 27, 2023 --- # Issue with Cache Preload * Resolved [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/) * Wanted to make your team aware of an apparent issue with Cache Preload. It appears that Cache Preload, when triggered has been making 6 requests to every URL on our site, swamping my CPU for upwards to an hour. Every day, between 6:00am ( Pacific) until about 7:00am, my server receives a storm of traffic from the local host IP address. Each request appears to be coming from its own thread. (see the consecutive port selected). * I’ve been observing this behavior for the last couple of weeks, as it’s been consistent for the time window on a daily basis. * It’s not a resource issue, as that Virtual Host has a 4 processor core with 16gb of memory. Apache and php-fm has been optimized for maximum performance. Firewall rate-limits are bypassed due to the fact that the traffic is coming from behind the firewall. (I don’t throttle internal requests) * WP-Optimize makes 6 requests to each page in each language (English & Spanish) on the site. In total, 3900 requests are made (every Page, Post & Event) . Although my back-end is built to support it, the subsequent processor spike essentially appears to be a denial of service attack, with all legitimate clients impacted during this processing window, with all site editors seeing performance issues in this window. * When I disable WP-Optimize Cache Preload, the traffic storm no longer occurs. * For example, (one page) from my logs: * For the page: [https://archseattle.org/about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice/](https://archseattle.org/about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice/) * Web Server IP 52.247.209.218 * WP-Optimize has made 6 requests within a second, which routes to my firewall ( Azure Front Door WAF) * 52.247.209.218:57822 – – [22/Nov/2023:15:04:44 +0000] “GET /about-the-archdiocese- of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/ 5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36” 52.247.209.218:57812 – – [22/Nov/2023:15:04: 44 +0000] “GET /about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/ 537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57800––[ 22/Nov/2023:15:04:44 +0000] “GET /about-the-archdiocese-of-seattle/archbishop- etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57838 – – [22/Nov/2023:15:04:44 +0000] “GET /about- the-archdiocese-of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794“-”“ Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57834 – – [22/Nov/2023: 15:04:44 +0000] “GET /about-the-archdiocese-of-seattle/archbishop-etienne/racial- justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218: 57848 – – [22/Nov/2023:15:04:44 +0000] “GET /about-the-archdiocese-of-seattle/ archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36” * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fissue-with-cache-preload%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 9 replies - 1 through 9 (of 9 total) * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17233599) * Hi, * There are several parameters you can play with to throttle the preload: – Using add_filter(‘wpoptimize_preload_delay’, ‘my_preload_delay_method’), you can override the delay between two pages, which is currently set at 500000 (1/2 a second). * – Using add_filter(‘wpo_page_cache_preload_memory_threshold’, 10485760); That filter lets you change how much memory should be left before interrupting the preload queue (10MB by default). * – Using add_filter(‘wpo_page_cache_preload_continue_interval’, 600); This filter enables to change the time before the preload resumes when interrupted (600s by Default). * Thread Starter [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17233821) * Thanks for the response.. Why though is every request for each time made 6 times? I like the ability to throttle requests, but what about the extra requests? Wouldn’t doing a HEAD vs GET be a little more efficient as well? * Thread Starter [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17233982) * Looking at the data, I assume that the preload delay would not apply to this 6 request issue, since your assertion is “delay between pages” would not apply, since it’s 6 requests to the same page? * A you can see, 6 requests with the exact same timestamp. * 52.247.209.218:57822 – – **[22/Nov/2023:15:04:44 +0000]** “GET /about-the-archdiocese- of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/ 5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36” 52.247.209.218:57812 – – **[22/Nov/2023:15: 04:44 +0000]** “GET /about-the-archdiocese-of-seattle/archbishop-etienne/racial- justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218: 57800 – – **[22/Nov/2023:15:04:44 +0000]** “GET /about-the-archdiocese-of-seattle/ archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57838 – –** [22/Nov/2023:15:04:44 +0000]** “GET / about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36( KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57834 – –**[ 22/Nov/2023:15:04:44 +0000]** “GET /about-the-archdiocese-of-seattle/archbishop- etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36”52.247.209.218:57848 – – **[22/Nov/2023:15:04:44 +0000]** “GET / about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice/ HTTP/1.1” 200 20794 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36( KHTML, like Gecko) Chrome/62.0.3202.89 Safari/537.36” * Plugin Support [Kowsar Hossain](https://wordpress.org/support/users/kowsar89/) * (@kowsar89) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17237603) 1. Do you have any multilingual plugins installed? If so, which one are you using? 2. Could you kindly provide a screenshot of the folder containing cached pages so that I can determine the number of files it contains? For instance, for the page at `https://archseattle.org/about-the-archdiocese-of-seattle/archbishop- etienne/racial-justice/`, the folder’s location might be `wp-content/cache/wpo- cache/about-the-archdiocese-of-seattle/archbishop-etienne/racial-justice`. As an illustrative example, in the screenshot linked here, you can observe that there are 5 files within that folder, screenshot: [https://prnt.sc/DXfuBGt5I-mH](https://prnt.sc/DXfuBGt5I-mH) * Thread Starter [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17239369) * ![](https://i0.wp.com/archseattle.org/wp-content/uploads/2023/11/CacheDirectoryCapture. png?ssl=1) * Only 3 files, not 5. * Thread Starter [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17239371) * Translation Plugin: WPML (current version) * Plugin Support [Kowsar Hossain](https://wordpress.org/support/users/kowsar89/) * (@kowsar89) * [2 years, 6 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17242393) * If you manually click the `Preload` button, does it also trigger 6 requests per URL? * Thread Starter [Kevin F Benz](https://wordpress.org/support/users/seattlearchdiocese/) * (@seattlearchdiocese) * [2 years, 5 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17251598) * Yes multiple, but in that case, 4 consecutive attempts * Plugin Support [Kowsar Hossain](https://wordpress.org/support/users/kowsar89/) * (@kowsar89) * [2 years, 5 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17253715) * And how many files are there in this case for a page? Would be helpful if you could share a screenshot Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘Issue with Cache Preload’ is closed to new replies. * ![](https://ps.w.org/wp-optimize/assets/icon-256x256.png?rev=1552899) * [WP-Optimize – Cache, Compress images, Minify & Clean database to boost page speed & performance](https://wordpress.org/plugins/wp-optimize/) * [Frequently Asked Questions](https://wordpress.org/plugins/wp-optimize/#faq) * [Support Threads](https://wordpress.org/support/plugin/wp-optimize/) * [Active Topics](https://wordpress.org/support/plugin/wp-optimize/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/wp-optimize/unresolved/) * [Reviews](https://wordpress.org/support/plugin/wp-optimize/reviews/) ## Tags * [page-cache](https://wordpress.org/support/topic-tag/page-cache/) * [preload](https://wordpress.org/support/topic-tag/preload/) * 9 replies * 3 participants * Last reply from: [Kowsar Hossain](https://wordpress.org/support/users/kowsar89/) * Last activity: [2 years, 5 months ago](https://wordpress.org/support/topic/issue-with-cache-preload/#post-17253715) * Status: resolved