Slow when reading from MongoDB using PHP mongodb driver with replica set

manpreet Best Answer 2 years ago

So when I connect to a MongoDB with multiple hosts, there is a delay in every one minute when executing a command. The delay time is exactly 10 seconds. I know this sounds so weird.

First I thought that the problem is related to MongoDB server configuration. But it only happens when I use PHP mongodb driver because it works fine when I tested with Java mongodb driver. - MongoDB Server: 3.6 - PHP mongodb driver: 1.5.3 - Java mongodb driver: 3.10.1

I also tested older version of PHP mongodb driver with the same problem.

PHP

// start tracking reading time
$start = microtime(true);

$m = new \MongoDB\Client('mongodb://rs1.host.com,rs2.host.com');
$db = $m->selectDatabase('test');
// slow when querying
$db->selectCollection('user')->findOne();

// end tracking reading time
$end = microtime(true);
$duration = $end - $start;

Full source code: https://drive.google.com/open?id=1r-EKiCntZbUq59sFzaBOiCrfy0tzjadt

Java

Date date1 = new Date();
long start = date1.getTime();

MongoClient mongoClient = MongoClients.create("mongodb://rs1.host.com,rs2.host.com");
MongoDatabase db = mongoClient.getDatabase("ple");

db.getCollection("user").find().first();

Date date2 = new Date();
long end = date2.getTime();

System.out.println((end - start) + "ms");

Full source code: https://drive.google.com/open?id=1TYTFrRxUiQUZdIUJdetllHpnOYHQiepd

I repeated the script above every 2 seconds, so here is result I tested:

PHP

0.013s
0.0056s
0.0135s
0.0052s
10.0271s (54sec from last delay)
0.0057s
0.0059s
0.0122s
0.0108s
0.0106s
0.0133s
0.014s
0.0095s
0.0076s
0.0145s
0.0102s
0.0148s
0.0058s
0.0132s
0.0125s
0.0134s
0.0056s
0.0055s
0.0135s
0.0124s
0.0116s
0.013s
0.013s
0.0139s
0.0135s
0.0132s
10.0234s (52sec from last delay)
0.0125s
0.0128s
0.0168s
0.0121s
0.0131s
0.0134s
0.0141s
0.0128s
0.0128s
0.0123s
0.0131s
0.0156s
0.006s
0.0053s
0.0058s
0.0136s
0.0131s
0.0139s
0.0131s
0.0063s
0.0125s
0.0127s
0.013s
0.0061s
0.0058s
10.015s (52sec from last delay)
0.0071s
0.0144s

Java

16ms
17ms
17ms
16ms
19ms
17ms
16ms
17ms
16ms
17ms
17ms
16ms
17ms
16ms
16ms
16ms

                                                

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