I have a module which is misbehaving. An EFQ is returing unexpected results, but I can't see why just by looking at the code. Is there a dpq() equivalent for EFQs? Other ways of debugging them?

  • Similar question: drupal.stackexchange.com/questions/33473/…. Can you cast the query object to a string to inspect it to see if the SQL gives any clues?
    – Clive
    Commented Jul 10, 2012 at 8:43
  • 1
    Great suggestions, however: Recoverable fatal error: Object of class EntityFieldQuery could not be converted to string :(
    – Letharion
    Commented Jul 10, 2012 at 8:50

6 Answers 6


It's a wee bit of a hack, but you could add a tag to any EntityFieldQuery you're interested in printing the query for, then implement hook_query_alter() to intercept it when it's a standard SelectQuery, then cast it to string for debugging:

function MYMODULE_query_alter($query) {
  if ($query->hasTag('efq_debug')) {

$q = new EntityFieldQuery;
$q->entityCondition('entity_type', 'node')

It's a bit of a hack but does the trick. The output for the above is:

SELECT node.nid AS entity_id, node.vid AS revision_id, node.type AS bundle, :entity_type     
AS entity_type
FROM {node} node

Presumably this will also only work when using MySQL as the field storage system.

  • Sounds great in theory, but what about the comments on the question? EFQ doesn't implement __toString()?
    – Letharion
    Commented Jul 20, 2012 at 11:19
  • 4
    By the time it gets to hook_query_alter() the query isn't an EntityFieldQuery any more, it's been converted down to a standard db_select(), so __tostring() works great :) Since working this out I've been using it quite a lot and it works pretty well
    – Clive
    Commented Jul 20, 2012 at 12:11
  • Confirmed that casting to string works once the query gets to hook_query_alter().
    – jhedstrom
    Commented Aug 27, 2012 at 21:09
  • To see the query argumentos (":entity_type" in the above example) you can use dpm($query->arguments());
    – sanzante
    Commented Nov 23, 2014 at 14:09

Rather than rolling your own hook_query_alter() you can let Devel module do the heavy lifting for you by adding the debug tag:

$q = new EntityFieldQuery;
$q->entityCondition('entity_type', 'node');

This will print the query to screen, just like dpq() would.


Adding to the @Clive answer, which generally prints the query with the placeholder not along with the value. To print the value with the query use the following code under the hook_query_alter.

function hook_query_alter($query) {
  if ($query->hasTag('debug')) {
    $sql = (string)$query;
    $connection = Database::getConnection();
    foreach ((array) $query->arguments() as $key => $val) {
      $quoted[$key] = $connection->quote($val);
    $sql = strtr($sql, $quoted);

$q = new EntityFieldQuery;
$q->entityCondition('entity_type', 'node');

It is not good practice to install a module for the few lines of code. That is why I opted for the aforementioned solution.


If you download the dev version of Nice DPQ (or anything => 1.1), you can simply do:

$user_query = new EntityFieldQuery();
$user_result = $user_query->execute();

and you will get the query dpm'ed nicely :). The important part in the code above is addTag('nicedpq') - that triggers the dpm().

  • nice alternate workaround to devel. Couldn't find that module directly over DO because they removed related module block which was there earliar.
    – kiranking
    Commented Oct 13, 2015 at 8:44

You can try to debug it via XDebug. Once installed, do xdebug_start_trace() before the code, and xdebug_stop_trace() after that, then you'll have clear trace log what was executed and where.

Also you can enable query logger in MySQL configuration.

The other method is to use strace/truss/dtruss like debuggers.

Example using dtruss:

  • all queries

    sudo dtruss -t read -n mysqld
  • specific queries

    sudo dtruss -t read -n mysqld 2>&1 | grep SPECIFIC_TEXT

Note that dtruss is just a script which uses DTrace, so you may consider a direct implementation of PHP DTrace static probes or DTracing MySQL by writing your own script.

Read more: Advanced debugging of Drupal core using the command line (strace & tcpdump)


Add this function to your module. Then, add the tag debug to any EFQ. Requires Devel module to be enabled in order to print the query.

 * Implements hook_query_TAG_alter().
 * Add the tag 'debug' to any EFQ and this will print the query to the messages.
 * @param \QueryAlterableInterface $query
function MYMODULE_query_debug_alter(QueryAlterableInterface $query) {
  if (function_exists('dpq') && !$query->hasTag('debug-semaphore')) {

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