Pull queries: Error in SELECT when ROWKEY contains the string null

[vpapavas]

Describe the bug
Assume a table with schema:
ROWTIME|ROWKEY|METRICS_NAME |CLUSTER|TOPIC_NAME|ENV|AVG_VALUE

Assume the table contains the following two rows:
|1571347727133 |fetch_latency_ms|+|null|+|null|+|staging : Window{start=1571347680000 end=-}|fetch_latency_ms|null|null|staging|9.44924| |1571347727133 fetch_latency_ms|+|cluster_lmn|+|topic_2|+|staging : Window{start=1571347680000 end=-} |fetch_latency_ms |cluster_lmn |topic_2 |staging| 7.988785

Note how the key contains the string null in the first row.

Issue query:
select * from metrics_table where rowkey='fetch_latency_ms|+|null|+|null|+|null';
Error reported:
Server Error

To Reproduce
Steps to reproduce the behavior, include:

1. The version of KSQL.
   Master
2. Sample source data.
   Provided above
3. Any SQL statements you ran
   Provided above

Expected behavior
Support rowkeys that contain the null string

Actual behaviour
A clear and concise description of what actually happens, including:

1. CLI output
   Server Error
2. Error messages
   Server Error
3. KSQL logs
   ksql-cli logs contain:
   [2019-10-17 15:47:15,556] ERROR Server Error (io.confluent.ksql.cli.console.Console:323)

Additional context
Add any other context about the problem here.

[purplefox]

Hi @vpapavas I am trying to understand what the '+' symbols represent in the example row:

|1571347727133 |fetch_latency_ms|+|null|+|null|+|staging : Window{start=1571347680000 end=-}|fetch_latency_ms|null|null|staging|9.44924|

Are you missing a '|' ?

[vpapavas]

Hey @purplefox !

Sorry I just saw your message.

This is how Ksql currently represents keys that consist of multiple columns.