adding a view to a merge table gives unexpected behaviour

[monetdb-team]

Date: 2019-02-22 10:00:07 +0100
From: @aris-koning
To: SQL devs <>
Version: 11.31.13 (Aug2018-SP2)
CC: @PedroTadim

Last updated: 2019-04-30 12:36:00 +0200

Comment 26902

Date: 2019-02-22 10:00:07 +0100
From: @aris-koning

User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0
Build Identifier:

There is no clear specification that allows or disallows views to be added to a merge table. This can lead to weird behaviour. See the reproduction steps.

Reproducible: Always

Steps to Reproduce:

1.create table foo (val int);
2.insert into foo values (1), (2), (3);
3.create view foo_view as select * from foo;
4.create merge table foo_merge_table (val int);
5.alter table foo_merge_table add table foo_view;
6.select * from foo_merge_table;

Actual Results:

operation successful
3 affected rows
operation successful
operation successful
operation successful
+-----+
| val |
+=====+
+-----+
0 tuples

Expected Results:

Either everything finishes succesfully and the final query returns all results in the view
or
an error message after submitting the alter table statement.

I am not sure what other merge table implementations handle alter table add view attempts.

Comment 26907

Date: 2019-02-27 11:28:21 +0100
From: MonetDB Mercurial Repository <>

Changeset ab619c893147 made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=ab619c893147

Changeset description:

Cannot add a view into a merge/remote/replica table. This fixes bug #6685.

Comment 26908

Date: 2019-02-27 11:30:02 +0100
From: @PedroTadim

We don't allow views to be added into merge/remote/replica tables.

Comment 26909

Date: 2019-02-27 11:53:01 +0100
From: @aris-koning

Changeset looks good to me.