Debug EntityFieldQuery?

Question

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?

Answer 1

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')) {
    dpm((string)$query);
  }
}

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

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.

Answer 2

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');
  ->addTag('debug')
  ->execute();

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

Answer 3

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, $quoted);
    dpm($sql);
  }
}


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

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

Answer 4

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

$user_query = new EntityFieldQuery();
$user_query->entityCondition('entity_type','user');
$user_query->addTag('nicedpq');
$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().

Answer 5

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)

Answer 6

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')) {
    $query->addTag('debug-semaphore');
    dpq($query);
  }
}