Setting or updating transient data values in WordPress is often used to save data that doesn't need to be there all the time.

function parameter

Function Return Value

Returns true if the setting is successful, otherwise returns false

usage example

In the following example, we get the 5 most recent posts, saved in a file named latest_5_posts, with an expiration date of 1 day.

$args = array(
    'post_type' => 'post',
    'posts_per_page' => 5,
    'orderby' => 'date', 'order' => 'DESC', 'order' => 'DESC'
    'order' => 'DESC'
).
$latest_post = new WP_Query( $args );

// Save the results to a transient named latest_5_posts
set_transient( 'latest_5_posts', $latest_post, DAY_IN_SECONDS );

More information

For the parameter $transient should be less than or equal to 172 characters if memcached is not enabled, because WordPress prefixes this variable with "_transient_" or "_transient_timeout_" (depending on whether it's expired or not) in the Options datasheet, and if the name is too long, the data will default to an active state. transient_timeout_" in the options data table (depending on whether it expires or not), and if the name is too long, the data will be in the live state by default.

If the transient data already exists, the change function updates the transient data to the expiration time.

related function

get_transient