when alpha Creating snapshot, the response time writing or querying of txn is takes several seconds

[raoshuaix1]

What version of Dgraph are you using?

Dgraph version : v1.1.0
Commit SHA-1 : ef7cdb2
Commit timestamp : 2019-09-04 00:12:51 -0700
Branch : HEAD
Go version : go1.12.7

Have you tried reproducing the issue with the latest release?

yes

What is the hardware spec (RAM, OS)?

32G ram, ubuntu18.04

Steps to reproduce the issue (command/config used to run Dgraph).

when alpha Creating snapshot, txn rpc request will time consuming increase.
It seems that all requests have been suspended, even if NewReadOnlyTxn is called.

Expected behaviour and actual result.

Return request results as soon as possible.
when alpha Creating snapshot, the response time writing or querying of txn is takes several seconds. Normal return takes only a few hundred milliseconds

[arijitAD]

We have observed this behavior and we are working on optimizing the snapshot creation. The fix should be out soon.

[dihmeetree]

Hoping we can get #4901 merged in soon! 🚀