Bug #67124 [Opn->Asn]: Typecast (bool) $array slowdown according to array length

Edit report at https://bugs.php.net/bug.php?id=67124&edit=1 ID: 67124 Updated by: johannes@php.net Reported by: vovan-ve at yandex dot ru Summary: Typecast (bool) $array slowdown according to array length -Status: Open +Status: Assigned Type: Bug Package: Performance problem Operating System: Linux PHP Version: Irrelevant -Assigned To: +Assigned To: dmitry Block user comment: N Private report: N New Comment: Yes, the guess is correct - we copy the array, then "convert" the copy see ZEND_CAST opcode handler http://lxr.php.net/xref/PHP_TRUNK/Zend/zend_operators.c#511 I don't see an obvious way to improve this without duplicating the conversion logic. You have an idea Dmitry? Previous Comments: ------------------------------------------------------------------------ [2014-04-27 07:19:04] hanskrentel at yahoo dot de Workaround to get the timings low in the test-script only. And I didn't meant that in a positive fashion. A workaround is always crap and expensive. However, as internally it might be easy to get the array value count, the internal function that so far converts array into boolean could be optimized by looking for such array count instead of iterating through it. And yes I did expect something else. I was quite astonished how expensive the bool cast is with arrays with more than 100 members. I didn't know that so far. I always expected casts to be quick, I hope this gets fixed. ------------------------------------------------------------------------ [2014-04-26 12:59:57] vovan-ve at yandex dot ru Yes, "workaround" to pass thru the bugs maze. Welcome to PHP. Did you expect something else?.. ------------------------------------------------------------------------ [2014-04-26 09:43:59] hanskrentel at yahoo dot de The workaround is to first count with arrays as the count is cached. (bool) count($array); ------------------------------------------------------------------------ [2014-04-24 04:47:35] vovan-ve at yandex dot ru Looks like array is copied while casting: # memory_limit=1G echo "Create array..."; $array = array_fill(0, 10 * 1000 * 1000, null); echo " ok\nCasting..."; $start = microtime(true); (bool) $array; printf(" %.3F sec.\n", microtime(true) - $start); Output: Create array... ok Casting...Fatal error: Allowed memory size of 1073741824 bytes exhausted (tried to allocate 35 bytes) in ... ------------------------------------------------------------------------ [2014-04-24 03:55:47] vovan-ve at yandex dot ru More clear test cases: $tests = array( 'empty' => array(), 'x10' => range(1, 10), 'x100' => range(1, 100), 'x1000' => range(1, 1000), ); Result: empty 0.15 sec. total x10 0.65 sec. total x100 5.14 sec. total x1000 49.91 sec. total ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=67124 -- Edit this bug report at https://bugs.php.net/bug.php?id=67124&edit=1