Using Redis Bitmap Operations for Precise User Sign‑in Statistics with PHP

Redis bitmap is a data structure that stores bits efficiently, enabling fast bit‑level operations such as setting, getting, and counting bits.

1. Introduction to Redis Bitmap Operations

Redis provides commands like BITSET, BITGET, and BITCOUNT to create, modify, and query bitmaps, allowing developers to perform precise statistical calculations.

2. Common Bitmap Commands

The BITSET command sets a specific bit to 0 or 1, BITGET retrieves the value of a bit, and BITCOUNT returns the number of bits set to 1 within a given range.

3. PHP Example – User Sign‑in Statistics

The following PHP script demonstrates how to record user sign‑ins using $redis->setbit() and obtain the total sign‑ins for a day with $redis->bitcount() . The code connects to Redis via Predis, defines userSign and getUserSignCount functions, records two users, and outputs the count.

setbit($key, $userId, 1);
}

function getUserSignCount($date)
{
    global $redis;
    $key = 'user_sign:' . $date;
    $count = $redis->bitcount($key);
    return $count;
}

// Record sign‑ins
$user1 = 1;
$user2 = 2;
$date = date('Ymd');
userSign($user1, $date);
userSign($user2, $date);

// Output count
$count = getUserSignCount($date);
echo "User sign‑in count: {$count}";
?>

4. Conclusion

Redis bitmap commands provide an efficient way to implement accurate counting features; by using BITSET/BITGET for manipulation and BITCOUNT for aggregation, developers can build fast statistics such as daily sign‑in totals, as illustrated in the PHP example.