Description:
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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:
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<?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:
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0.0065169334411621

Actual result:
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5.0267069339752