dubbo zookeeper registry too slow

[qixiaobo]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.6.x
• Operating System version: *nix
• Java version: 1.7

Steps to reproduce this issue

1. xxx
2. xxx
3. xxx

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

What do you expected from the above steps？

Actual Result

What actually happens?

We can see code like this

   @Override
    public void create(String path, boolean ephemeral) {
        if (!ephemeral) {
            if (checkExists(path)) {
                return;
            }
        }
        int i = path.lastIndexOf('/');
        if (i > 0) {
            create(path.substring(0, i), false);
        }
        if (ephemeral) {
            createEphemeral(path);
        } else {
            createPersistent(path);
        }
    }

You can see recursive here.
If we have a lot of dubbo reference or service.
This method would execute too many times and cost a large time.
In fact , if dubbo group is same then the path may no need to check every time

[qixiaobo]

[qixiaobo]

2019-08-15 14:17:54,187 [myid:] - INFO [ProcessThread(sid:0 cport:2181)::PrepRequestProcessor@653] - Got user-level KeeperException when processing sessionid:0x1004228f12d5154 type:create cxid:0x495 zxid:0x7c8c87 txntype:-1 reqpath:n/a Error Path:/f6-test/XXX/providers Error:KeeperErrorCode = NodeExists for /f6-test/XXX/providers

[qixiaobo]

tail -n 10000 zookeeper.out |grep NodeExists|wc -l
9732
We can see almost 97% NodeExistsException