Topic on Project:Support desk

I'm trying to write an own maintenance script.

I want to update a custom column in the page table using the age of the page. Therefor I have to query revision.rev_timestamp.

But

foreach( $res as $row ) {				
				
  $page_id = $row->page_id;
				
  $res = $db->select("revision", "rev_timestamp", "rev_page = $page_id", "ORDER BY `rev_timestamp` ASC LIMIT 1", __METHOD__); //timestamp of page creation date
  $mySQLtimestamp = $db->fetchObject( $res );
  ...

Gives me the error: "Catchable fatal error: Object of class stdClass could not be converted to string"

	public function execute() {
		$db = wfGetDB( DB_MASTER );

		$start = $db->selectField( 'page', 'MIN(page_id)', false, __METHOD__ );
		if( !$start ) {
			$this->error( "Nothing to do.", true );
		}
		$end = $db->selectField( 'page', 'MAX(page_id)', false, __METHOD__ );
	
		# Do remaining chunk
		$end += $this->mBatchSize - 1;
		$blockStart = $start;
		$blockEnd = $start + $this->mBatchSize - 1;
		while( $blockEnd <= $end ) {
			$this->output( "...doing page_id from $blockStart to $blockEnd\n" );
			
			$cond = "page_id BETWEEN $blockStart AND $blockEnd;

			$res = $db->select('page', array('page_id', 'page_custom', 'page_counter', 'page_namespace', 'page_title'), $cond, __METHOD__ );

			foreach( $res as $row ) {				
				
				$page_id = $row->page_id;
				
				$res = $db->select("revision", "rev_timestamp", "rev_page = $page_id", "ORDER BY `rev_timestamp` ASC LIMIT 1", __METHOD__); //timestamp of page creation date
				$mySQLtimestamp = $db->fetchObject( $res );
				#$mySQLtimestamp returns: Catchable fatal error: Object of class stdClass could not be converted to string
				
				$namespace = $row->page_namespace;
				$pagetitle = $row->page_title;
				$fooVal = someFunction($namespace, $pagetitle);

				#update page_custom using $fooVal and $mySQLtimestamp
				
			}
			$blockStart += $this->mBatchSize - 1;
			$blockEnd += $this->mBatchSize - 1;
			wfWaitForSlaves( 5 );
		}		
		
		$this->output( "...Done!\n" );
	}

How can this be fixed?

Does it die when running "$mySQLtimestamp = $db->fetchObject($res)" or does it die on a missing debug line where you try to print $mySQLtimestamp as a string?

fetchObject returns an object of type stdclass, so you probably want something like this:

$mySQLtimestamp = $db->fetchObject($res)->rev_timestamp;

->rev_timestamp - that's it! Thanks brion! :)