无论如何用PHP做MongoDB分片？

Question

I have started using MongoDB for one of my PHP project. In that database, i am trying to use MongoDB sharding concept. I got the below link and tried,

MongoDB Sharding Example

It is working well. But the problem is, in the above example, everything is done in command prompt. But i am trying to do everything in PHP. I am not able to get any example in PHP.

So far, i have started with these piece of codes,

    $connection =   new Mongo();
    $db     =   $connection->selectDB('TestDB');
    $db     =   $connection->TestDB;

    $connection->selectDB('admin')->command(array('addshard'=>'host:port'));
    $connection->selectDB('admin')->command(array('enablesharding'=>'TestDB'));
    $connection->selectDB('admin')->command(array('shardcollection'=>'TestDB.large', 'key' => '_id'));

It is not working. Also, i dont know how to set shard servers and config database in PHP.

Is there any other way to do MongoDB sharding in PHP?

Answer 1

MongoDB's database commands are case-sensitive. You were passing in lowercase command names, while the real commands are camelCased (see: sharding commands ). Additionally, the key paremeter of shardCollection needs to be an object.

A corrected version of your above code would look like:

$connection->selectDB('admin')->command(array('addShard'=>'host:port'));
$connection->selectDB('admin')->command(array('enableSharding'=>'TestDB'));
$connection->selectDB('admin')->command(array('shardCollection'=>'TestDB.large', 'key' => array('_id' => 1)));

Additionally, you should have been able to examine the command result of to determine why this wasn't working. The ok field would be zero, and an errmsg field would explain the error (eg "no such cmd: addshard").

Lastly, if you're attempting to mimic the shell's functionality to configure sharding in PHP, you may realize that some of the shell methods are more than just database commands. For any of those methods, you can get the JS source by omitting the parentheses. For example:

> sh.addTagRange
function ( ns, min, max, tag ) {
    var config = db.getSisterDB( "config" );
    config.tags.update( {_id: { ns : ns , min : min } } ,
            {_id: { ns : ns , min : min }, ns : ns , min : min , max : max , tag : tag } ,
            true );
    sh._checkLastError( config );
}

That would be a useful hint for what an addTagRange() function in PHP would need to do.