[FLINK-22075] Incorrect null outputs in left join

• Type: Bug
• Status: In Progress
• Priority: Not a Priority
• Resolution: Unresolved
• Affects Version/s: 1.12.2
• Component/s: Table SQL / API
• Labels: auto-deprioritized-critical auto-deprioritized-major auto-deprioritized-minor auto-unassigned

Environment

https://github.com/jamii/streaming-consistency/blob/4e5d144dacf85e512bdc7afd77d031b5974d733e/pkgs.nix#L25-L46

```
[nix-shell:~/streaming-consistency/flink]$ java -version
openjdk version "1.8.0_265"
OpenJDK Runtime Environment (build 1.8.0_265-ga)
OpenJDK 64-Bit Server VM (build 25.265-bga, mixed mode)

[nix-shell:~/streaming-consistency/flink]$ flink --version
Version: 1.12.2, Commit ID: 4dedee0

[nix-shell:~/streaming-consistency/flink]$ nix-info
system: "x86_64-linux", multi-user?: yes, version: nix-env (Nix) 2.3.10, channels(jamie): "", channels(root): "nixos-20.09.3554.f8929dce13e", nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos
```

• Assignee: Unassigned
• Reporter: Jamie Brandon
• Created: 31/Mar/21 18:10
• Updated: 04/Feb/22 10:36

Description

I'm left joining a table with itself [here](https://github.com/jamii/streaming-consistency/blob/4e5d144dacf85e512bdc7afd77d031b5974d733e/flink/src/main/java/Demo.java#L55-L66). The output should have no nulls, or at least emit nulls and then retract them. Instead I see:

```
jamie@machine:~/streaming-consistency/flink$ wc -l tmp/outer_join_with_time
100000 tmp/outer_join_with_time
jamie@machine:~/streaming-consistency/flink$ grep -c insert tmp/outer_join_with_time
100000
jamie@machine:~/streaming-consistency/flink$ grep -c 'null' tmp/outer_join_with_time
16943
```

~1.7% of the outputs are incorrect and never retracted.

[Full output](https://gist.githubusercontent.com/jamii/983fee41609b1425fe7fa59d3249b249/raw/069b9dcd4faf9f6113114381bc7028c6642ca787/gistfile1.txt)