php batching sql query build performance

explode_vs_str_repeat.php

<?php

/**
 * If you build SQL queries like INSERT INTO table ('f1', 'f2', ...) VALUES ('v1', 'v2', ...), ('v1', 'v2', ...), ...
 * You should know what
 *
 * Expression
 *      `rtrim(str_repeat('?,', TRY_COUNT), ',');`
 * works 16 time faster than
 *      `implode(',', array_pad([], TRY_COUNT, '?'));`
 */

declare(strict_types=1);

const TRY_COUNT = 1_000;
const PLACEHOLDERS_COUNT = 1_000;

printf("try on count %d\n", TRY_COUNT * PLACEHOLDERS_COUNT);

$startTime = microtime(true);
for ($i = 0; $i < TRY_COUNT; $i++) {
    for ($j = 0; $j < PLACEHOLDERS_COUNT; $j++) {
        implode(',', array_pad([], TRY_COUNT, '?'));
    }
}
$implodeResult = microtime(true) - $startTime;
printf("implode time: %f\n", $implodeResult);

$startTime = microtime(true);
for ($i = 0; $i < TRY_COUNT; $i++) {
    for ($j = 0; $j < PLACEHOLDERS_COUNT; $j++) {
        rtrim(str_repeat('?,', TRY_COUNT), ',');
    }
}
$strRepeatResult = microtime(true) - $startTime;
printf("str_repeat time: %f\n", $strRepeatResult);

printf('str_repeat faster than implode in %f times', $implodeResult / $strRepeatResult);