Lightweight use of transients
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The document discusses the WordPress Transients API, which provides a standardized method for temporarily storing cached data in the database with expiration times. It highlights advantages and downsides of using transients, including potential database fragmentation and performance issues. The author recommends setting longer expiration times, managing transient cleanup actively, and ensuring unique identifiers are used for transient keys.
![“WordPress Transients API […]
offers a simple and standardized
way of storing cached data in the
database temporarily […]
44
https://codex.wordpress.org/Transients_API](https://image.slidesharecdn.com/transients-170522085651/85/Lightweight-use-of-transients-4-320.jpg)
![“WordPress Transients API […]
offers a simple and standardized
way of storing cached data in the
database temporarily by giving it
a […] timeframe after which it will
expire and be deleted.
88
https://codex.wordpress.org/Transients_API](https://image.slidesharecdn.com/transients-170522085651/85/Lightweight-use-of-transients-8-320.jpg)
![“▰In wp_options was about 7000
rows (1,5 Gb). […]
At the moment 672 rows (2,6
Mb).
19
https://theeventscalendar.com/support/forums/topic/large-number-of-transients-in-wp_options-table/](https://image.slidesharecdn.com/transients-170522085651/85/Lightweight-use-of-transients-19-320.jpg)
Lightweight use of transients
- 2. Phil Marx @JustPhilMarx www.nerdtalk.de / phil.marx@gmail.com Works with WordPress since v2.x 2
- 3. WHAT ARE TRANSIENTS? A short roundup 3 1
- 4. “WordPress Transients API […] offers a simple and standardized way of storing cached data in the database temporarily […] 44 https://codex.wordpress.org/Transients_API
- 5. Examples for Transients ▰Results of complex queries ▰Results of remote calls ▰Complex aggregations of different values 5
- 6. Advantage: Simple usage ▰set_transient() – sets a transient ▻ set_transient( $transient, $value, $expiration ); ▰get_transient() – gets a transient ▻ get_transient( $transient ); ▰delete_transient() – deletes a transient ▻ delete_transient( $transient ); 6
- 7. Transients are designed to expire ▰set_transient() – sets a transient ▻ set_transient( $transient, $value, $expiration ); ▰get_transient() – gets a transient ▻ get_transient( $transient ); ▰delete_transient() – deletes a transient ▻ delete_transient( $transient ); 7
- 8. “WordPress Transients API […] offers a simple and standardized way of storing cached data in the database temporarily by giving it a […] timeframe after which it will expire and be deleted. 88 https://codex.wordpress.org/Transients_API
- 10. Downsides of deletion ▰Leads to database fragmentation ▻Can cause slow database performance ▰A new dataset is created for the same content ▻Just… why?! 10
- 11. What codex recommends if(false===$value=get_transient('value’))) { // this code runs when there is no valid transient set } https://codex.wordpress.org/Transients_API 11
- 12. My approach to a lightweight use of transients ▰Set a expiration time in a far away future ▰Set an own timeout and update! 12 If a transient exists, this function will update the transient's expiration time. https://codex.wordpress.org/Function_Reference/set_transient
- 13. Code example // Setting my own timeout $timeout_transient = 60 * 5; $stream = get_transient('streaminglive'); // Fallback if transient was deleted before expiration if (!is_object($stream)) $stream = new stdClass; // I'll save the last check into a variable "last_check" (see below) - if the transient is expired based on my timeout, renew it if (!isset($stream->last_check) || $timeout_stream < (time() - $stream->last_check)) { // Do whatever you need to get/update your data $stream->last_check = time(); /* Attention: - The timeout of the transient is much more than my personal timeout - set_transient checks, if there is a valid transient and will update it instead of creating a new one */ set_transient('streaminglive', $stream, 60 * 60); } 13
- 14. 14 Expired transients are only deleted, if they‘re requested again
- 15. CLEAN UP YOUR OWN TRANSIENTS! Just. Do. It! 15 3
- 16. Causes for not requesting transients anymore ▰Adding unique identifier to transient key ▻(Session ID, time(), some hashes, …) ▰Forget deletion when deactivating plugins/themes 16
- 17. Expired and orphaned transients need to be deleted manually ▰Plugins ▻ „Delete expired transients“ ▰SQL Queries ▻Only useful in combination with cronjobs / WP-Cron 17
- 18. “▰We deleted about 143,513 rows of transient entries bringing the wp_options table from 8Gb to 200mb 18 https://theeventscalendar.com/support/forums/topic/large-number-of-transients-in-wp_options-table/
- 19. “▰In wp_options was about 7000 rows (1,5 Gb). […] At the moment 672 rows (2,6 Mb). 19 https://theeventscalendar.com/support/forums/topic/large-number-of-transients-in-wp_options-table/
- 20. DON’T LET THE USER DO YOUR WORK!
- 21. Don‘t be that guy! ▰Tidy up after deactivation of your theme / plugin ▻ delete_transient( $transient ); ▰Use WP Cron event to delete orphaned transients ▻delete-transients-by-prefix.php (GitHub) 21
- 23. Be lightweight! ▰Add your own timeout ▰Think if you need unique identifier which are for temporary usage ▰Clean up your transients 23
- 24. 24 THANKS!Any questions? You can find me at @JustPhilMarx / nerdtalk.de phil.marx@gmail.com Thanks to - SlidesCarnival for Slides template and Icons (CC BY 4.0) - Alexandru Zdrobău for girl photo (CC0)