Broadband IP address query Application of PHP dichotomy in IP address query

The database probably stores hundreds of thousands of IP records, and the record set is as follows:
+----------+----------+------------ +---------+----------+--------+--------+
| ip_begin | ip_end | country_id | prov_id | city_id | isp_id | netbar |
+----------+----------+------------+-------- -+---------+--------+--------+
| 0 | 16777215 | 2 | 0 | 0 | 0 | 0 |
| 16777216 | 33554431 | 2 | 0 | 0 | 0 | 33554432 | 50331647 | 2 | 0 | 0 | 0 |
| 50331648 | 67108863 | 3 | 0 | 0 | 0 |
| 67108864 | 678297 59 | 3 | 0 0 | 0 0 0 ------+---------+--------+--------+
　To do this query, you need to use the following SQL:
$sql = 'SELECT * FROM i_m_ip WHERE ip_begin <= $client_ip AND ip_end >= $client_ip';
?>
　 Such a search obviously does not use an index. Even if it does, the MySQL query efficiency is unlikely Reaching more than 500 times per second, I did a lot of concurrency optimization, but the final average query efficiency was only about 200 times per second, which was really a headache. At the beginning, I also thought of using the retrieval method of the Innocence IP library, but I have always been resistant to the algorithm and thought that the dichotomy method was difficult, so I did not try to use it. It was not until I had no other choice in the end that I finally realized the dichotomy IP address retrieval method. .
From the above table, you can see that the IP library is a continuous value from 0 to 4294967295. If this value is separated and stored, there will be hundreds of gigabytes of data, so there is no way to use indexes and no way to hash. In the end, I used PHP to convert these things into binary storage, abandoning database retrieval. You can see that the starting and ending length of the IP is a 4-byte long integer. The following country ID, province ID, etc. can be stored using a 2-byte short integer. A total of one row of data has 18 bytes, a total of 31 Ten thousand pieces of data only add up to 5M.The specific IP library generation code is as follows:
/*
IP file format:
3741319168 3758096383 182 0 0 0 0
3758096384 3774873599 3 0 0 0 0
3774873600 4026531839 182 0 0 0 0
4026531840 4278190079 182 0 0 0 0
4294967040 4294967295 312 0 0 0 0
*/
set_time_limit(0);
$handle = fopen('./ip.txt', 'rb');
$fp = fopen("./ip.dat ", 'ab');
if ($handle) {
while (!feof($handle)) {
$buffer = fgets($handle);
$buffer = trim($buffer);
$buffer = explode ("t", $buffer);
foreach ($buffer as $key => $value) {
$buffer[$key] = (float) trim($value);
$str = pack(' L', $buffer[0]);
$str .= pack('L', $buffer[1]);
$str .= pack('S', $buffer[2]);
$str . = pack('S', $buffer[3]);
$str .= pack('S', $buffer[4]);
$str .= pack('S', $buffer[5]);
                  $str .= pack('S',  $buffer[6]);                           fwrite($fp,  $str); , so it is easy to use the binary method to retrieve the IP information:
function getip($ip, $fp) {
fseek($fp, 0);
$begin = 0;
$end = filesize('./ip .dat');
$begin_ip = implode('', unpack('L', fread($fp, 4)));
fseek($fp, $end - 14);
$end_ip = implode('' , unpack('L', fread($fp, 4)));
$begin_ip = sprintf('%u', $begin_ip);
$end_ip = sprintf('%u', $end_ip);
do {
                                                                                                                                                                                               lode('', unpack('S ', fread($fp, 2)));
                                                                                                                                                       ', unpack('S', fread($fp, 2)));
                                                                                                           $info[ 4] = implode('', unpack('S', fread($fp, 2)));
 Le $ MIDDLE_SEEK = CEIL (($ End-$ Begin)/18)*18+$ Begin;
Fseek ($ FP, $ Middle_seek); ' , fread($fp, 4)));
$middle_ip = sprintf('%u', $middle_ip);
if ($ip >= $middle_ip) {
$begin = $middle_seek;
           } else {
$ END = $ MIDDLE_SEEK;
}} While (TRUE);
}
$ FP is the file handle of the ip.dat. Because it is a circular search, it is written outside the function. , the 30W row data dichotomy method only needs to cycle about 7 times (2^7) at most to find the accurate IP information. Later, I originally wanted to put ip.dat in the memory to speed up the retrieval. Later I found that the efficiency of the string positioning function was not at the same order of magnitude as the offset positioning of the file pointer, so I gave up using memory to store the IP library.
　This implementation has improved the IP retrieval efficiency by nearly a hundred times. It is just a simple application of the dichotomy. From then on, the concept that the algorithm is not important in WEB applications has been completely dispelled. In fact, to achieve this, I also asked Jinhu for advice. I initially asked him to help me generate an IP library in a pure format, and then use Discuz's IP query function to search for it. However, he refused to help me, and finally created my This practice and learning. Sometimes, it is better to ask for others than to ask for yourself.

The above introduces the application of broadband IP address query and PHP dichotomy in IP address query, including the content of broadband IP address query. I hope it will be helpful to friends who are interested in PHP tutorials.