Title: Duplicate posts from custom import
Last modified: August 20, 2016

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# Duplicate posts from custom import

 *  [jklapel](https://wordpress.org/support/users/jklapel/)
 * (@jklapel)
 * [14 years ago](https://wordpress.org/support/topic/duplicate-posts-from-custom-import/)
 * I work at a radio station and have built a plugin that automatically builds a
   playlist on our site from what plays on the radio. It starts by querying an XML
   playlist file output by our radio streaming server. If the plugin has not seen
   a song played at a specific time before, it will create a new post (itself a 
   custom post type called “Song”) for that XML song entry. Then I have a shortcode
   that just runs a WP_Query for posts of type “Song” and outputs the most recent.
 * The problem is this: the XML is queried every time someone opens a page that 
   calls the shortcode. When we get a lot of people visiting our site, we will end
   up with duplicate posts of the same song at the same time. I presume this is 
   because two people happened to query the XML file and the WP_Query at the same
   time, which resulted in neither of them finding the song and so both of them 
   adding the post. I’m trying to find a way to prevent this duplication from happening,
   but so far, I haven’t come up with much. Any ideas would be appreciated.

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * (@bcworkz)
 * [14 years ago](https://wordpress.org/support/topic/duplicate-posts-from-custom-import/#post-2768743)
 * If you re-query the data base for duplicate posts immediately before a new post,
   it would minimize duplicates. Or maybe you are doing this? I don’t fully understand
   what’s happening when in your scenario.
 * It should be possible to invoke exclusive write access to the posts table while
   your plugin checks for duplicates and makes a new post. If WP doesn’t have this
   sort of privilege, your plugin could establish it’s own lock system by storing
   a lock value as an option to prevent other instances of itself from writing at
   the same time. You may need to do a cache flush to ensure the lock value is valid
   in real time and not a cached value.
 *  Thread Starter [jklapel](https://wordpress.org/support/users/jklapel/)
 * (@jklapel)
 * [14 years ago](https://wordpress.org/support/topic/duplicate-posts-from-custom-import/#post-2768821)
 * bcworkz, you are correct, I am already doing this. I run a WP_Query and then 
   the very next line is an if statement that leads into an insert_post statement
   so there is very little time between query and post insertion.
 * I haven’t seen any sort of write locking in WordPress, though I have been looking.
   I was hoping to avoid writing my own database access methods, but it looks like
   I just might have to do that. I also tried to use PHP semaphores, but then I 
   found out that the shared hosting I am on doesn’t have the PHP semaphores package
   installed.
 * If anyone has any further ideas, I’ll gladly accept them. Thanks!

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Duplicate posts from custom import’ is closed to new replies.

## Tags

 * [custom post](https://wordpress.org/support/topic-tag/custom-post/)
 * [duplicate posts](https://wordpress.org/support/topic-tag/duplicate-posts/)
 * [radio](https://wordpress.org/support/topic-tag/radio/)
 * [wp_query](https://wordpress.org/support/topic-tag/wp_query/)

 * In: [Hacks](https://wordpress.org/support/forum/plugins-and-hacks/hacks/)
 * 2 replies
 * 2 participants
 * Last reply from: [jklapel](https://wordpress.org/support/users/jklapel/)
 * Last activity: [14 years ago](https://wordpress.org/support/topic/duplicate-posts-from-custom-import/#post-2768821)
 * Status: not resolved

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