has(predicate) query at root level sometimes leaks nodes that do _not_ have the predicate

[billylindeman]

If you suspect this could be a bug, follow the template.

• What version of Dgraph are you using?

Dgraph version   : v1.0.5
Commit SHA-1     : 82787414
Commit timestamp : 2018-04-20 15:50:53 +1000
Branch           : HEAD

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Licensed under Apache 2.0 + Commons Clause. Copyright 2015-2018 Dgraph Labs, Inc.```

• Have you tried reproducing the issue with latest release?
  yes

• Steps to reproduce the issue (command/config used to run Dgraph).
  Intermittently a has() query at root level will return nodes that do not have the predicate in it.

In the following screenshot, I have a query that should return all nodes with has(type.company), but sometimes will return nodes of a different type.

This seems to happen after a long running query of that other type. I'd suspect it has something to do with the caching layer?

[sboorlagadda]

is it not consistent and does happen sometimes?

[billylindeman]

Unfortunately it is not consistently reproducible . It seems that shutting down / starting the dgraph server node fixes it when it starts happening.

[billylindeman]

Pinging on this @sboorlagadda @manishrjain
Any insight into what is happening?

[manishrjain]

Sorry, haven't had a chance to look at this yet. If you have steps that we could take to reproduce this problem, they'd help.

[billylindeman]

@manishrjain this happens on our dataset only with has(predicate) queries, and only after dgraph has been running for a long time. If I reboot the dgraph server it does not happen. I can't really provide reproduction steps more than that, but that should give some indication of where to look? It must be a caching issue of some sort?

[manishrjain]

This should be fixed by #2585.