Wordpress LScache Plugin: Server overload when clear cache
Last Updated on: Wed, 15 Apr 2026 00:00:02 Hi, Each time a post is published, whether publish instantly or via cron job, it make the site inaccessible for around 3 minutes due to high server load, it rocks 10 times the normal server load. The cache purge setting as showed: https://imgur.com/F565LZA Checking SQL Process I saw a lot of Creating sort index queries: SELECT SQL_CALC_FOUND_ROWS wp_posts.ID FROM wp_posts WHERE 1=1 AND wp_posts.post_type = post AN Report number: HHPFMWHO I dont know since which version the issue happens, I just notice it recently. Thank you. This topic was modified 2 years, 6 months ago by longnha. Hi, If your site has a lot of traffic , then after cache is purged when you publish something , then it could result as all the request are directly hitting PHP process. Best regards, Ruikai. Hi, Isnt there a better way to handle the cache purge such as batch purge instead of purge everything at once? Thank you. Hi, In Cache setting ?> Purge ?> there is an option called Purge Stale , please try enable it and see if it helps. Best regards, I do see the Purge Stale option but it make no different, so no idea whether or not it works! Is there a way to confirm that? I still think limit numbers of cache purge at one time is a better idea, W3 cache has such options. Thank you. Hi, If you still see cache: hit after purge , then it means the stale cache is working. Based on your setting , it should only purge the relevant pages, instead of all the caches , therefore should not create an overload like this. Please try , if you uncheck all of them , how does it go ? Best regards, When uncheck all of them, no cache is purged. Thank you. Checking the Web Admin, I also see unusual behavior. Normally, when the cache is cleared I should see a drop in Public Cache Hits/Sec and increase Req/Sec to the server. But the recent event show that the rate increase for both! I also unchecked Purge Stale as it makes no different at my end. Thank you. Hi, May I know if your site has a lot of pages ? and incoming traffic are always into different pages ? When uncheck all of them, no cache is purged. when no cache is purged , you still see request number raise up a lot ? Best regards, May I know if your site has a lot of pages ? and incoming traffic are always into different pages ? The site has around 40k post, 400 cats and around 4k tags. when no cache is purged , you still see request number raise up a lot ? Its normal load, nothing changes when no cache is purged. As I have no idea on how to troubleshoot this issue, I downgraded to version 2.9.8.7 and it backs to normal so it should be some changes in new version that caused the issue, not my side. Thanks. Hi, Could you please compare if both v2.9 setting and v3.0 setting are same ? I did see in some rare case some setting got lost during upgrade. Perhaps some setting caused additional load. And also if you could try on v3 with default setting ? Checking SQL Process I saw a lot of Creating sort index queries: SELECT SQL_CALC_FOUND_ROWS wp_posts.ID FROM wp_posts WHERE 1=1 AND wp_posts.post_type = post AN Do you also see this on v2.9 ? Best regards,
LiteCache Rush: Speed comes from using less, not from doing it faster
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