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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