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query with union all silently crashes #6069

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monetdb-team opened this issue Nov 30, 2020 · 0 comments
Closed

query with union all silently crashes #6069

monetdb-team opened this issue Nov 30, 2020 · 0 comments

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@monetdb-team monetdb-team commented Nov 30, 2020

Date: 2016-10-05 18:22:51 +0200
From: muesli4
To: SQL devs <>
Version: 11.23.7 (Jun2016-SP1)
CC: @njnes

Last updated: 2016-12-21 13:07:43 +0100

Comment 24461

Date: 2016-10-05 18:22:51 +0200
From: muesli4

User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:49.0) Gecko/20100101 Firefox/49.0
Build Identifier:

The following query fails silently:

WITH t1(x) AS (
SELECT 0
FROM (values (0)) as v(x)
), t2(x) AS (
SELECT 0
FROM ( SELECT 0, 0, 0, 0, 0, 0, 0
UNION ALL
SELECT 1, 0, 0, 0, 0, 0, 0
) AS a23(x1, x2, x3, x4, x5, x6, x7)
)
SELECT 0 FROM t1, t2;

Reproducible: Always

Steps to Reproduce:

  1. Run the query.
  2. Wonder that there is no output.

Actual Results:

None.

Expected Results:

There should be a result with cardinality 2.

It seems somehow related to the projection lists within the UNION ALL: Whenever I remove one of the zeroes (or change the 1 to a 0), the expected result appears.

Revision: http://dev.monetdb.org/hg/MonetDB/rev/08b99a61d03c

Comment 24462

Date: 2016-10-05 18:23:52 +0200
From: muesli4

Created attachment 471
A reduced example showing the bug.

Attached file: bug3.sql (application/sql, 289 bytes)
Description: A reduced example showing the bug.

Comment 24480

Date: 2016-10-11 20:04:21 +0200
From: muesli4

One thing I noticed, is that it only happens, when the amount of columns doesn't match with those specified in the schema in the from clause, but only if there are more than 6 columns. The following fails:
select 0 from (select 0, 0, 0, 0, 0, 0, 0 union all select 1, 0, 0, 0, 0, 0, 0) as t(a, b, c, d, e, f, g), (values (0)) as v(x);

While this query is perfectly fine:
select 0 from (select 0, 0, 0, 0, 0, 0 union all select 1, 0, 0, 0, 0, 0) as t(a, b, c, d, e, f), (values (0)) as v(x);

This is what the log file says for the already posted snippet:

2016-10-11 19:59:19 ERR test[7024]: could not find L17.L17
2016-10-11 19:59:19 ERR test[7024]: L10.L10
2016-10-11 19:59:19 ERR test[7024]: L11.L11
2016-10-11 19:59:19 ERR test[7024]: L12.L12
2016-10-11 19:59:19 ERR test[7024]: L13.L13
2016-10-11 19:59:19 ERR test[7024]: L14.L14
2016-10-11 19:59:19 ERR test[7024]: L15.L15
2016-10-11 19:59:19 ERR test[7024]: L16.L10
2016-10-11 19:59:19 ERR test[7024]: L16.L11
2016-10-11 19:59:19 ERR test[7024]: L16.L12
2016-10-11 19:59:19 ERR test[7024]: L16.L13
2016-10-11 19:59:19 ERR test[7024]: L16.L14
2016-10-11 19:59:19 ERR test[7024]: L16.L15

Comment 24482

Date: 2016-10-12 18:57:21 +0200
From: MonetDB Mercurial Repository <>

Changeset 8d48879598e2 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=8d48879598e2

Changeset description:

created simple fix for bug #6069, but lots of tests got new output (ie L.. changes)

Comment 24483

Date: 2016-10-12 18:59:55 +0200
From: @njnes

resolved by properly naming al expressions

Comment 24485

Date: 2016-10-12 19:02:45 +0200
From: MonetDB Mercurial Repository <>

Changeset 3b06c3df35f7 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=3b06c3df35f7

Changeset description:

added test for bug #6069
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