Records with a JSON column aren't deleted correctly

[melvynator]

Describe what's wrong

Record with a JSON column seems to not be deleted correctly.

Does it reproduce on recent release?

Yes

How to reproduce

First let's create the table with a JSON column.

CREATE TABLE testJson
(
    `id` UInt32,
    `fields` JSON
)
ENGINE = ReplicatedMergeTree
ORDER BY id
SETTINGS index_granularity = 8192

Let's add a row to the table:

INSERT INTO testJson  (id, fields) VALUES (1,'{"fieldInteger":1,"fieldBoolean":true,"fieldFloat":1.23,"fieldString":"StringValue"}');

Let's check that the row has been properly inserted.

SELECT *
FROM testJson

Query id: 62875aa8-67fc-46ee-80b3-382346bbf255

┌─id─┬─fields───────────────────┐
│  1 │ (1,1.23,1,'StringValue') │
└────┴──────────────────────────┘

1 row in set. Elapsed: 0.158 sec.

Then I delete the element

ALTER TABLE testJson
    DELETE WHERE id = 1

Query id: 288c33ed-75c4-42fc-ac04-bbce2cc325e3

┌─host──────────────────────────┬─status─┬─error─┬─num_hosts_remaining─┬─num_hosts_active─┐
│ default|host-1 │      0 │       │                   1 │                1 │
└───────────────────────────────┴────────┴───────┴─────────────────────┴──────────────────┘
┌─host──────────────────────────┬─status─┬─error─┬─num_hosts_remaining─┬─num_hosts_active─┐
│ default|host-2 │      0 │       │                   0 │                0 │
└───────────────────────────────┴────────┴───────┴─────────────────────┴──────────────────┘

2 rows in set. Elapsed: 0.366 sec.

Let's verify that the record has been deleted:

SELECT *
FROM testJson

Query id: 62875aa8-67fc-46ee-80b3-382346bbf255

┌─id─┬─fields───────────────────┐
│  1 │ (1,1.23,1,'StringValue') │
└────┴──────────────────────────┘

1 row in set. Elapsed: 0.158 sec.

The record is still there.

Expected behavior

The row should have been deleted like in the below example:

CREATE TABLE testString
(
    `id` UInt32,
    `fields` String
)
ENGINE = ReplicatedMergeTree
ORDER BY id
SETTINGS index_granularity = 8192

Let's insert a row:

INSERT INTO testString  (id, fields) VALUES (1,'test');

Let's check that the record is there:

SELECT *
FROM testString

Query id: b2f8f509-3633-43fc-9be7-a797492df0bb

┌─id─┬─fields─┐
│  1 │ test   │
└────┴────────┘

1 rows in set. Elapsed: 0.202 sec.

Let's remove it:

ALTER TABLE testJson
    DELETE WHERE id = 1

Query id: 10ad5930-9102-4297-96c3-ae1fdef09d50

┌─host──────────────────────────┬─status─┬─error─┬─num_hosts_remaining─┬─num_hosts_active─┐
│ default|host-1 │      0 │       │                   1 │                1 │
└───────────────────────────────┴────────┴───────┴─────────────────────┴──────────────────┘
┌─host──────────────────────────┬─status─┬─error─┬─num_hosts_remaining─┬─num_hosts_active─┐
│ default|host-2│      0 │       │                   0 │                0 │
└───────────────────────────────┴────────┴───────┴─────────────────────┴──────────────────┘

2 rows in set. Elapsed: 0.339 sec.

It's being deleted correctly:

SELECT *
FROM testString

Query id: fe3c0ea5-cc5a-41c0-be69-04c12d80cd93

Ok.

0 rows in set. Elapsed: 0.156 sec.