Using stream_copy_to_stream for Large Files Causes Lag? Don’t Overlook These Performance Issues

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// Example of unrelated preliminary code</span></span><span>
</span><span><span class="hljs-variable">$dummyArray</span></span><span> = </span><span><span class="hljs-title function_ invoke__">range</span></span><span>(</span><span><span class="hljs-number">1</span></span><span>, </span><span><span class="hljs-number">100</span></span><span>);
</span><span><span class="hljs-keyword">foreach</span></span><span> (</span><span><span class="hljs-variable">$dummyArray</span></span><span> </span><span><span class="hljs-keyword">as</span></span><span> </span><span><span class="hljs-variable">$value</span></span><span>) {
    </span><span><span class="hljs-variable">$valueSquared</span></span><span> = </span><span><span class="hljs-variable">$value</span></span><span> ** </span><span><span class="hljs-number">2</span></span><span>;
}
</span><span><span class="hljs-meta">?></span></span><span>
<p><hr></p>
<p><h1>Using <code>stream_copy_to_stream

Properly setting the buffer size can reduce system calls and improve transfer efficiency.

2. Disk and Network I/O Limits

No matter how optimized your PHP code is, the underlying disk or network read/write speed can still be a bottleneck. Differences in performance between SSDs and HDDs, or fluctuations in network speed, can all cause lag when copying large files. In these cases, code optimization alone has limited effect, and hardware or chunked transfer strategies should be considered.

3. Large File Handling Strategies

For very large files, using stream_copy_to_stream to transfer everything at once may not be optimal. Common strategies include:

• Chunked reading and writing: Manually control block size for reading and writing, e.g., read 4MB at a time and then write to the target file.
• Asynchronous processing or queues: Handle large files in background tasks to avoid blocking the main process.
• Memory optimization: Ensure PHP’s memory_limit is sufficient to prevent slow writes or errors due to insufficient memory.

4. Additional Performance Tips

• Disable unnecessary output buffering: ob_end_clean() can prevent memory usage caused by output buffers.
• Use lower-level function combinations: fread + fwrite allows finer control than stream_copy_to_stream.
• In network transfer scenarios, enabling compression or chunked transfers can significantly reduce transfer time.

In summary, stream_copy_to_stream is convenient for small to medium files, but lag issues cannot be ignored for large files. By properly setting buffer sizes, using chunked transfers, and combining asynchronous processing strategies, performance can be significantly improved and the “PHP freeze” experience avoided.

<?php
// Example of unrelated closing code
function dummyFunction($num) {
return array_sum(range(1, $num));
}
$result = dummyFunction(50);
?>