# wpdb::flush
The `wpdb::flush()` method in WordPress is used to clear the internal cache of the `wpdb` object.
When you perform database queries using the `wpdb` class (e.g., `$wpdb->get_results()`, `$wpdb->query()`), WordPress often caches the results of these queries internally within the `wpdb` object to improve performance. This means that if the same query is executed multiple times within a single request, the cached result might be returned instead of re-querying the database.
Calling `wpdb::flush()` will clear this internal cache, forcing `wpdb` to re-query the database for subsequent operations, even if the same query was previously executed and cached.
When to use `wpdb::flush()`:
-
When you know the database has been modified by external means or another part of your code that doesn't use `wpdb`'s caching mechanisms.
If you're directly interacting with the database outside of the standard `wpdb` methods, or if another system is modifying the data, `flush()` can ensure your `wpdb` queries reflect the latest state.
-
**During development or debugging:**
If you're seeing unexpected cached results and need to ensure you're always getting fresh data from the database, `flush()` can be helpful.
Example:
Code
``` global $wpdb; // Perform a query, results are cached $results1 = $wpdb->get_results( "SELECT * FROM {$wpdb->prefix}options WHERE option_name = 'my_option'" ); // Clear the wpdb internal cache $wpdb->flush(); // Perform the same query again, it will now re-query the database $results2 = $wpdb->get_results( "SELECT * FROM {$wpdb->prefix}options WHERE option_name = 'my_option'" ); ```