Bug #70092 [Ana]: pg_field_type() is too slow

Edit report at https://bugs.php.net/bug.php?id=70092&edit=1 ID: 70092 Updated by: yohgaki@php.net Reported by: yohgaki@php.net Summary: pg_field_type() is too slow Status: Analyzed Type: Bug Package: PostgreSQL related PHP Version: master-Git-2015-07-17 (Git) Assigned To: yohgaki Block user comment: N Private report: N New Comment: Simply freed smart_str instead of setting length to 0. PHP7/master without --enable-debug [yohgaki@dev PHP-master]$ ./php-bin ../t.php pg_field_type(): 0.0013771057128906 pg_field_name(): 0.00064301490783691 pg_field_type(): 0.00048398971557617 Fedora22's PHP 5.6 [yohgaki@dev PHP-master]$ php ../t.php pg_field_type(): 0.0018699169158936 pg_field_name(): 0.0012152194976807 pg_field_type(): 0.0011649131774902 Previous Comments: ------------------------------------------------------------------------ [2015-07-25 19:28:33] yohgaki@php.net @cmb Thanks! I thought it seems freeing is required, too. I'll check the behavior using gdb later. ------------------------------------------------------------------------ [2015-07-25 14:05:58] cmb@php.net Simply setting the length of the smart_string's zend_string to zero[1] won't work, because that causes the same zend_string to be used as key of the list hashtable again and again. Instead it seems that the smart_string's zend_string has to be free (see the attached patch "pg_field_type"). Yasuo, please have a look at this issue. [1] <https://github.com/php/php-src/blob/php-7.0.0beta2/ext/pgsql/pgsql.c#L2371> ------------------------------------------------------------------------ [2015-07-25 14:04:43] cmb@php.net The following patch has been added/updated: Patch Name: pg_field_type Revision: 1437833083 URL: https://bugs.php.net/patch-display.php?bug=70092&patch=pg_field_type&revision=1437833083 ------------------------------------------------------------------------ [2015-07-25 12:41:41] cmb@php.net For some reason the buffering of the field names in get_field_name() does not work, and so for each call to pg_field_type() the else clause ("hash all oids")[1] is executed again. [1] <https://github.com/php/php-src/blob/php-7.0.0beta2/ext/pgsql/pgsql.c#L2349> ------------------------------------------------------------------------ [2015-07-17 21:16:58] yohgaki@php.net Description: ------------ Somehow pg_field_type() became very slow. Other functions that share the same code pg_field_name()/etc is not affected. Test script: --------------- <?php $db = pg_connect('host=localhost') or die('Cannot connect db'); $res = pg_query('SELECT * FROM test'); $start = microtime(true); for ($i = 0; $i < 10000; $i++) { pg_field_type($res, 1); } echo 'pg_field_type(): '.(microtime(true)-$start)."\n"; $start = microtime(true); for ($i = 0; $i < 10000; $i++) { pg_field_name($res, 1); } echo 'pg_field_name(): '.(microtime(true)-$start)."\n"; $start = microtime(true); for ($i = 0; $i < 10000; $i++) { pg_field_size($res, 1); } echo 'pg_field_type(): '.(microtime(true)-$start)."\n"; Expected result: ---------------- pg_filed_type() should be as fast as pg_filed_name()/etc Actual result: -------------- PHP 7 and master [yohgaki@dev PHP-master]$ ./php-bin ../t.php pg_field_type(): 3.1048510074615 pg_field_name(): 0.0023491382598877 pg_field_type(): 0.0014290809631348 PHP 5.6 [yohgaki@dev PHP-master]$ php ../t.php pg_field_type(): 0.0019080638885498 pg_field_name(): 0.0013489723205566 pg_field_type(): 0.0010430812835693 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=70092&edit=1