The log_query_custom_data WordPress PHP Filter allows you to modify the custom data logged alongside a SQL query.
Usage
add_filter('log_query_custom_data', 'my_custom_log_query_data', 10, 5);
function my_custom_log_query_data($query_data, $query, $query_time, $query_callstack, $query_start) {
// your custom code here
return $query_data;
}
Parameters
$query_data(array) – Custom query data.$query(string) – The SQL query.$query_time(float) – Total time spent on the query, in seconds.$query_callstack(string) – Comma-separated list of the calling functions.$query_start(float) – Unix timestamp of the time at the start of the query.
More information
See WordPress Developer Resources: log_query_custom_data
Examples
Add the user ID to the logged data
Add the current user ID to the query data, so you can see which user triggered the query.
function add_user_id_to_query_data($query_data, $query, $query_time, $query_callstack, $query_start) {
$current_user_id = get_current_user_id();
$query_data['user_id'] = $current_user_id;
return $query_data;
}
add_filter('log_query_custom_data', 'add_user_id_to_query_data', 10, 5);
Log the current page URL
Log the current page URL alongside the query data.
function log_page_url($query_data, $query, $query_time, $query_callstack, $query_start) {
$current_url = home_url($_SERVER['REQUEST_URI']);
$query_data['current_url'] = $current_url;
return $query_data;
}
add_filter('log_query_custom_data', 'log_page_url', 10, 5);
Log memory usage
Log the memory usage at the time of the query.
function log_memory_usage($query_data, $query, $query_time, $query_callstack, $query_start) {
$memory_usage = memory_get_usage();
$query_data['memory_usage'] = $memory_usage;
return $query_data;
}
add_filter('log_query_custom_data', 'log_memory_usage', 10, 5);
Log the query type
Determine and log the type of SQL query (e.g., SELECT, INSERT, UPDATE).
function log_query_type($query_data, $query, $query_time, $query_callstack, $query_start) {
$query_type = strtoupper(substr(trim($query), 0, 6));
$query_data['query_type'] = $query_type;
return $query_data;
}
add_filter('log_query_custom_data', 'log_query_type', 10, 5);