Streaming Large Database Results

Read result rows incrementally to avoid allocating a large PHP array.

The objective is to understand the behavior and operational limits, not only the method name.

What It Does

Read result rows incrementally to avoid allocating a large PHP array.

Prerequisites

Use a dedicated development environment and sample data. Where a snippet uses an injected connection, repository, request value or mailer, supply it from your own application setup.

Example 1: Basic Use

A focused working pattern for this topic. Names such as $pdo, $authContext and $repo represent dependencies provided by the application unless initialized in the snippet.

<?php
$pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
$stmt = $pdo->query('SELECT id, payload FROM logs ORDER BY id');
while (($row = $stmt->fetch(PDO::FETCH_ASSOC)) !== false) {
    processRow($row);
}
$stmt->closeCursor();

Example 2: A Second Scenario

A second use case that adds a different operation or data flow specific to this topic.

<?php
$stmt = $pdo->query('SELECT id, created_at FROM events ORDER BY id');
while (($row = $stmt->fetch(PDO::FETCH_ASSOC)) !== false) {
    processEvent($row);
}

Example 3: Practical Checks

A practical validation, failure or deployment concern specific to this topic.

<?php
$pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
$stmt = $pdo->query('SELECT id FROM export_rows ORDER BY id');
try { while (($id = $stmt->fetchColumn()) !== false) echo $id . PHP_EOL; }
finally { $stmt->closeCursor(); }

Important Behavior and Edge Cases

MySQL buffered queries may still consume memory in the driver; disable buffering when appropriate.

For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Read result rows incrementally to avoid allocating a large PHP array.
• MySQL buffered queries may still consume memory in the driver; disable buffering when appropriate.
• Use this workflow as a focused starting point rather than a substitute for application-level tests.

Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.