Consecutive queries on a transaction causes StartTs mismatch

[d0nutptr]

When using a Txn to perform two queries in a row, dgraph errors out with a message stating StartTs mismatch.

You should be able to get that behavior if you do the following:

let mut txn = client.txn();

// Should work okay!
match txn.query("q(func: uid(0x01)) { uid }".to_string()) {
    Ok(result) => {},
    Err(e) => println!(e)
}

// StartTs mismatch (Err!)
match txn.query("q(func: uid(0x01)) { uid }".to_string()) {
    Ok(result) => {},
    Err(e) => println!(e)
}

Thanks for making this library!

[d0nutptr]

I don't really understand what's happening to cause this, but I've temporarily removed the start_ts check in merge_context in txn.rs and this issue has gone away. Of course, I can't help but think that this is A Really Bad Idea (tm).

[ondrowan]

Thanks for reporting this. I've fixed the issue in version 0.3.1. Could you, please, try if it fixed your problem?

[d0nutptr]

Hey @ondrowan so sorry about this long delay.

It does appear that the issue has been fixed. Unfortunately, the current version of grpc used appears to have some issues around an invalid pointer in a free invocation.

That being said, this particular issue has been solved as far as I'm concerned.