What potential issues can arise when trying to retrieve and display files stored as BLOB data in PHP?

When retrieving and displaying files stored as BLOB data in PHP, potential issues can arise due to memory limitations when handling large files. To solve this, it is recommended to use output buffering and read the BLOB data in chunks instead of loading the entire file into memory at once. 

// Retrieve BLOB data from database
$query = "SELECT file_data FROM files WHERE id = ?";
$stmt = $pdo->prepare($query);
$stmt->execute([$fileId]);
$fileData = $stmt->fetchColumn();

// Output BLOB data in chunks
$chunkSize = 1024;
$offset = 0;
while ($offset < strlen($fileData)) {
    echo substr($fileData, $offset, $chunkSize);
    $offset += $chunkSize;
}

Keywords

BLOB data file retrieval display PHP error handling

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