get_transient( string $transient ): mixed
- Since
- 2.8.0
- Source
wp-includes/option.php:1431
Retrieves the value of a transient.
Description
If the transient does not exist, does not have a value, or has expired, then the return value will be false.
Compatibility
- WordPress
- since 2.8.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$transientstring- Transient name. Expected to not be SQL-escaped.
Return value
mixed- Value of transient.
Performance profile
How much work a call to get_transient() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Moderate
- Scaling
- Constant
- Instructions
- 11–61
- Plugin surface
- 2 hooks
- Called by
- 23
Reads stored settings via get_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 68.
Third-party callbacks on 'pre_transient_{$transient}', 'transient_{$transient}' run inside this call, and their cost is not bounded by anything here.
23 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- transienttransient
get_transient()this function does it - hookthird-party callbacks
apply_filters()called directly - cacheobject cache
wp_cache_get()called directly - optionoption read or write
get_option()called directly - serializeserialisation
maybe_unserialize()one call below get_transient()
Further down the call graph this can also reach query. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 12 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost get_transient() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
$pre !== false | 11 | apply_filters() |
$pre === false && wp_using_ext_object_cache() | 26 | apply_filters(), wp_using_ext_object_cache(), wp_cache_get(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && isset($value) | 29 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && wp_installing() | 29 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_cache_get(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !isset($value) | 33 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), get_option(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && isset($alloptions[$transient_option]) && isset($value) | 34 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() | 38–46 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && !isset($alloptions[$transient_option]) && $timeout === false && !isset($value) | 50 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), get_option(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && !isset($alloptions[$transient_option]) && $timeout !== false && !$timeout && isset($value) | 50 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), time(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && !isset($alloptions[$transient_option]) && $timeout !== false && !$timeout && !isset($value) | 54 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), time(), get_option(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && !isset($alloptions[$transient_option]) && $timeout !== false && $timeout && isset($value) | 57 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), time(), delete_option(), delete_option(), apply_filters() |
$pre === false && !wp_using_ext_object_cache() && !wp_installing() && !isset($alloptions[$transient_option]) && $timeout !== false && $timeout && !isset($value) | 61 | apply_filters(), wp_using_ext_object_cache(), wp_installing(), wp_installing(), wp_load_alloptions(), get_option(), time(), delete_option(), delete_option(), get_option(), apply_filters() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 68 instructions, 11–61 executed per call, 8 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 2
2 hooks fire while get_transient() runs, in this order:
- apply_filters( pre_transient_{$transient} )filterline 1449 (+18 into the body)
Filters the value of an existing transient before it is retrieved.
- apply_filters( transient_{$transient} )filterline 1491 (+60 into the body)
Filters an existing transient's value.
Uses · 8
- apply_filters()Calls the callback functions that have been added to a filter hook.
- wp_using_ext_object_cache()Toggles `$_wp_using_ext_object_cache` on and off without directly touching global.
- wp_installing()Checks or sets whether WordPress is in "installation" mode.
- wp_cache_get()Retrieves the cache contents from the cache by key and group.
- wp_load_alloptions()Loads and caches all autoloaded options, if available or all options.
- wp_prime_option_caches()Primes specific options into the cache with a single database query.
- get_option()Retrieves an option value based on an option name.
- delete_option()Removes an option by name. Prevents removal of protected WordPress options.
Used by · 23
- Featured_Content::get_featured_post_ids()Gets featured post IDs.
- RSSCache::check_cache()
- RSSCache::get()
- WP_Site_Health::enqueue_scripts()Enqueues the site health scripts.
- WP_oEmbed_Controller::get_proxy_item()Callback for the proxy API endpoint.
- clean_dirsize_cache()Cleans directory size cache used by recurse_dirsize().
- get_settings_errors()Fetches settings errors registered by add_settings_error().
- install_themes_feature_list()Retrieves the list of WordPress theme features (aka theme tags).
- is_multi_author()Determines whether this site has more than one author.
- recurse_dirsize()Gets the size of a directory recursively.
- register_core_block_style_handles()Registers core block style handles.
- spawn_cron()Sends a request to run cron through HTTP request that doesn't halt page loading.
Show all 23
- twentyfifteen_categorized_blog()Determines whether blog/site has more than one category.
- twentyfourteen_categorized_blog()Finds out if blog has more than one category.
- twentyseventeen_categorized_blog()Returns true if a blog has more than 1 category.
- twentysixteen_categorized_blog()Determines whether blog/site has more than one category.
- wp_add_global_styles_for_blocks()Adds global style rules to the inline style for each block.
- wp_dashboard_cached_rss_widget()Checks to see if all of the feed url in $check_urls are cached.
- wp_dashboard_plugins_output()Display plugins text for the WordPress news widget.
- wp_dashboard_site_health()Displays the Site Health Status widget.
- wp_maybe_generate_attachment_metadata()Maybe attempts to generate attachment metadata, if missing.
- wp_rand()Generates a random non-negative number.
- wp_start_scraping_edited_file_errors()Starts scraping edited file errors.
Source code
function get_transient( $transient ) { /** * Filters the value of an existing transient before it is retrieved. * * The dynamic portion of the hook name, `$transient`, refers to the transient name. * * Returning a value other than false from the filter will short-circuit retrieval * and return that value instead. * * @since 2.8.0 * @since 4.4.0 The `$transient` parameter was added * * @param mixed $pre_transient The default value to return if the transient does not exist. * Any value other than false will short-circuit the retrieval * of the transient, and return that value. * @param string $transient Transient name. */ $pre = apply_filters( "pre_transient_{$transient}", false, $transient ); if ( false !== $pre ) { return $pre; } if ( wp_using_ext_object_cache() || wp_installing() ) { $value = wp_cache_get( $transient, 'transient' ); } else { $transient_option = '_transient_' . $transient; if ( ! wp_installing() ) { // If option is not in alloptions, it is not autoloaded and thus has a timeout. $alloptions = wp_load_alloptions(); if ( ! isset( $alloptions[ $transient_option ] ) ) { $transient_timeout = '_transient_timeout_' . $transient; wp_prime_option_caches( array( $transient_option, $transient_timeout ) ); $timeout = get_option( $transient_timeout ); if ( false !== $timeout && $timeout < time() ) { delete_option( $transient_option ); delete_option( $transient_timeout ); $value = false; } } } if ( ! isset( $value ) ) { $value = get_option( $transient_option ); } } /** * Filters an existing transient's value. * * The dynamic portion of the hook name, `$transient`, refers to the transient name. * * @since 2.8.0 * @since 4.4.0 The `$transient` parameter was added * * @param mixed $value Value of transient. * @param string $transient Transient name. */ return apply_filters( "transient_{$transient}", $value, $transient );}Changelog
Introduced in 2.8.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/option.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.