select + group by expression alias from a view breaks connection
Hi, i hit a strange problem when using alias for an expression in group by i run into this with a complex view containing multiple UNION ALL queries but after a while everything boiled down to a fairly simple test case that will always produce the error Welcome to mclient, the MonetDB/SQL interactive terminal (Feb2013-SP1) Database: MonetDB v11.15.3 (Feb2013-SP1), 'mapi:monetdb://lux-analytics:50000/zkdev1' Type \q to quit, \? for a list of available commands auto commit mode: on sql>CREATE VIEW mmtest_v AS SELECT date'2012-01-01' as period, 1 as quantity; operation successful (213.074ms) sql>SELECT extract(month from period) as m, count(1) as cnt FROM mmtest_v GROUP BY m; *Connection terminated* I am on Ubuntu 12.04.2 LTS As the alias in GROUP BY works in other cases i expect this is a bug - pls confirm and i will be happy to file it. BTW it looks like MonetDB has generally issues with selects from more complex views - i.e. views based on another view(s). In such cases the results do not match expectations or there is even an error. I can reproduce the problem but i only on quite large set of data (typically 20+ mil. records) and after some data manipulation got involved, so i cannot give a simple test case as above. Any idea how to pass such problem (when large data-set is involved) to the development team? Thanks in advance milan
On Fri, Mar 29, 2013 at 11:02:54AM +0100, Budulinku Dejmihrasku wrote:
Hi, i hit a strange problem when using alias for an expression in group by i run into this with a complex view containing multiple UNION ALL queries but after a while everything boiled down to a fairly simple test case that will always produce the error
Welcome to mclient, the MonetDB/SQL interactive terminal (Feb2013-SP1) Database: MonetDB v11.15.3 (Feb2013-SP1), 'mapi:monetdb:// lux-analytics:50000/zkdev1' Type \q to quit, \? for a list of available commands auto commit mode: on sql>CREATE VIEW mmtest_v AS SELECT date'2012-01-01' as period, 1 as quantity; operation successful (213.074ms) sql>SELECT extract(month from period) as m, count(1) as cnt FROM mmtest_v GROUP BY m; Connection terminated Could you create a bug report for this?
I am on Ubuntu 12.04.2 LTS As the alias in GROUP BY works in other cases i expect this is a bug - pls confirm and i will be happy to file it.
BTW it looks like MonetDB has generally issues with selects from more complex views - i.e. views based on another view(s). In such cases the results do not match expectations or there is even an error. I can reproduce the problem but i only on quite large set of data (typically 20+ mil. records) and after some data manipulation got involved, so i cannot give a simple test case as above. Any idea how to pass such problem (when large data-set is involved) to the development team?
Niels
Thanks in advance milan
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-- Niels Nes, Centrum Wiskunde & Informatica (CWI) Science Park 123, 1098 XG Amsterdam, The Netherlands room L3.14, phone ++31 20 592-4098 sip:4098@sip.cwi.nl url: http://www.cwi.nl/~niels e-mail: Niels.Nes@cwi.nl
On Fri, Mar 29, 2013 at 11:02:54AM +0100, Budulinku Dejmihrasku wrote:
Hi, i hit a strange problem when using alias for an expression in group by i run into this with a complex view containing multiple UNION ALL queries but after a while everything boiled down to a fairly simple test case that will always produce the error
Welcome to mclient, the MonetDB/SQL interactive terminal (Feb2013-SP1) Database: MonetDB v11.15.3 (Feb2013-SP1), 'mapi:monetdb:// lux-analytics:50000/zkdev1' Type \q to quit, \? for a list of available commands auto commit mode: on sql>CREATE VIEW mmtest_v AS SELECT date'2012-01-01' as period, 1 as quantity; operation successful (213.074ms) sql>SELECT extract(month from period) as m, count(1) as cnt FROM mmtest_v GROUP BY m; Connection terminated Could you create a bug report for this?
I can indeed reproduce the segfault --- thanks for reporting and providing this easy test! Could you indeed please file a bug report including your example to reproduce the problem? Could you then possibly also attach to the bug report the gdb trace I attach to this email? It shows the location and cause of the segfault.
I am on Ubuntu 12.04.2 LTS As the alias in GROUP BY works in other cases i expect this is a bug - pls confirm and i will be happy to file it.
BTW it looks like MonetDB has generally issues with selects from more complex views - i.e. views based on another view(s). In such cases the results do not match expectations or there is even an error. I can reproduce the problem but i only on quite large set of data (typically 20+ mil. records) and after some data manipulation got involved, so i cannot give a simple test case as above. Any idea how to pass such problem (when large data-set is involved) to the development team?
It would be great if you could provide us --- preferably via bug report(s) --- as much information as possiblet to reproduce the problems, such that we can analyze them. For sharing large data sets (if possible; or data generators, if available), we'll need to find for each individual case a solution that is more suitable than attaching them to a bug report. Stefan
Niels
Thanks in advance milan
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-- Niels Nes, Centrum Wiskunde & Informatica (CWI) Science Park 123, 1098 XG Amsterdam, The Netherlands room L3.14, phone ++31 20 592-4098 sip:4098@sip.cwi.nl url: http://www.cwi.nl/~niels e-mail: Niels.Nes@cwi.nl
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-- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
On 3/29/2013 11:36 AM, Stefan Manegold wrote:
On Fri, Mar 29, 2013 at 11:02:54AM +0100, Budulinku Dejmihrasku wrote:
Hi, i hit a strange problem when using alias for an expression in group by i run into this with a complex view containing multiple UNION ALL queries but after a while everything boiled down to a fairly simple test case that will always produce the error
Welcome to mclient, the MonetDB/SQL interactive terminal (Feb2013-SP1) Database: MonetDB v11.15.3 (Feb2013-SP1), 'mapi:monetdb:// lux-analytics:50000/zkdev1' Type \q to quit, \? for a list of available commands auto commit mode: on sql>CREATE VIEW mmtest_v AS SELECT date'2012-01-01' as period, 1 as quantity; operation successful (213.074ms) sql>SELECT extract(month from period) as m, count(1) as cnt FROM mmtest_v GROUP BY m; Connection terminated Could you create a bug report for this? I can indeed reproduce the segfault --- thanks for reporting and providing this easy test!
Could you indeed please file a bug report including your example to reproduce the problem?
Could you then possibly also attach to the bug report the gdb trace I attach to this email? It shows the location and cause of the segfault.
done - *Bug 3264* http://bugs.monetdb.org/show_bug.cgi?id=3264
I am on Ubuntu 12.04.2 LTS As the alias in GROUP BY works in other cases i expect this is a bug - pls confirm and i will be happy to file it.
BTW it looks like MonetDB has generally issues with selects from more complex views - i.e. views based on another view(s). In such cases the results do not match expectations or there is even an error. I can reproduce the problem but i only on quite large set of data (typically 20+ mil. records) and after some data manipulation got involved, so i cannot give a simple test case as above. Any idea how to pass such problem (when large data-set is involved) to the development team? It would be great if you could provide us --- preferably via bug report(s) --- as much information as possiblet to reproduce the problems, such that we can analyze them. For sharing large data sets (if possible; or data generators, if available), we'll need to find for each individual case a solution that is more suitable than attaching them to a bug report.
Stefan
ok - thanks hopefully we find time soon enough to prepare+scramble some data set to reproduce the issues i mentioned we are generally happy with MonetDB and this is the least we can do to help you improve :) milan
Niels
Thanks in advance milan _______________________________________________ users-list mailing list users-list@monetdb.org http://mail.monetdb.org/mailman/listinfo/users-list
-- Niels Nes, Centrum Wiskunde & Informatica (CWI) Science Park 123, 1098 XG Amsterdam, The Netherlands room L3.14, phone ++31 20 592-4098 sip:4098@sip.cwi.nl url: http://www.cwi.nl/~niels e-mail: Niels.Nes@cwi.nl
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participants (3)
-
Budulinku Dejmihrasku -
Niels Nes -
Stefan Manegold