Bug #68548 [Opn->Fbk]: slow calls to mysqli_fetch_field when using MYSQLI_STORE_RESULT_COPY_DATA

Edit report at https://bugs.php.net/bug.php?id=68548&edit=1 ID: 68548 Updated by: cmb@php.net Reported by: ryan dot brothers at gmail dot com Summary: slow calls to mysqli_fetch_field when using MYSQLI_STORE_RESULT_COPY_DATA -Status: Open +Status: Feedback Type: Bug Package: MySQLi related Operating System: Linux PHP Version: 5.6.3 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: The other bug has been fixed, so I wonder whether that resolved this issue as well. Previous Comments: ------------------------------------------------------------------------ [2019-02-11 02:32:36] ryan dot brothers at gmail dot com I just submitted bug 77597, where now in PHP 7.3.2, calling mysqli_fetch_field hangs the script completely. ------------------------------------------------------------------------ [2016-05-31 20:38:08] notvalid at gmail dot com Also of note, CPU utilization is maxed out during the delay in returning the list of fields. On a result set with over 1m rows, MYSQLI_STORE_RESULT_COPY_DATA results in over a 30 minute call to fetch_fields() while disabling MYSQLI_STORE_RESULT_COPY_DATA returns data from fetch_fields() almost immediately. ------------------------------------------------------------------------ [2014-12-05 04:15:40] ryan dot brothers at gmail dot com Description: ------------ I am seeing an issue where calls to mysqli_fetch_field() are very slow when using MYSQLI_STORE_RESULT_COPY_DATA. In the below example, the call to fetch_field takes 5 seconds to run. If the below is changed to call store_result() without MYSQLI_STORE_RESULT_COPY_DATA, then the call to fetch_field takes 0.006 seconds to run. Is there a way that the time to call fetch_field could be improved when using MYSQLI_STORE_RESULT_COPY_DATA? I have placed SQL to create a test table of 100,000 rows at https://drive.google.com/uc?export=download&id=0B37DKbJklxg_Y3NadnRjc2tVbE0. Thanks for your help. Test script: --------------- <?php $mysqli = new mysqli('localhost', 'test', 'test', 'test'); $mysqli->real_query("SELECT * FROM a"); $result = $mysqli->store_result(MYSQLI_STORE_RESULT_COPY_DATA); $start = microtime(true); $field = $result->fetch_field(); echo microtime(true) - $start."\n"; exit; Expected result: ---------------- 0.0065169334411621 Actual result: -------------- 5.0267069339752 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=68548&edit=1