May 2012 - users-list

[MonetDB-users] timeout while waiting for database 'xxx' to initialise the sql scenario
by Brian J. Cardiff 11 May '12

11 May '12

Hi all, I'm trying monetdb among with other vertical databases. After some experiments I am unable to start the database again. I'm not sure what the things I did cause the issue, but happens twice already. I have restart monetdbd and server without luck. Is there any way to solve this issue? $ monetdb start xxx starting database 'xxx'... FAILED start: starting 'xxx' failed: timeout while waiting for database 'xxx' to initialise the sql scenario The experiments consist on: 1. Bulk load .csv file with ~ 20*10^6 records 2. Do some aggregate functions with "SELECT AVG(..) FROM TBL WHERE ID IN (...)" with different amount of ids in list (10 - 5000) (yeap, ugly). 3. Add columns to TBL, Massive update columns in TBL, Drop columns in TBL. [version] MonetDB Database Server Toolkit v1.0 (Apr2012) MonetDB Database Server v1.6 (Apr2012) [morovingian.log] 2012-05-11 15:05:55 MSG xxx[637]: # Listening for UNIX domain connection requests on mapi:monetdb:///Users/bcardiff/Work/Xxx/db/xxx/.mapi.sock 2012-05-11 15:05:55 MSG xxx[637]: # MonetDB/GIS module loaded 2012-05-11 15:05:55 MSG xxx[637]: # MonetDB/SQL module loaded 2012-05-11 15:06:05 MSG merovingian[588]: sending process 637 (database 'xxx') the TERM signal 2012-05-11 15:06:05 MSG merovingian[588]: database 'xxx' has shut down 2012-05-11 15:06:05 MSG merovingian[588]: database 'xxx' (637) has exited with exit status 0 2012-05-11 15:06:05 ERR control[588]: (local): failed to fork mserver: timeout while waiting for database 'xxx' to initialise the sql scenario -- Brian J. Cardiff - Manas Technology Solutions [ar.phone] 4796.0232 #BCR(227) [us.phone] 312.612.1050 #BCR(227) [email] bcardiff(a)manas.com.ar [web] www.manas.com.ar [weblog] http://weblogs.manas.com.ar/bcardiff/

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[MonetDB-users] Using monetdb and sqlalchemy
by sabst＠free.fr 10 May '12

10 May '12

Hi, I am just starting using monetdb and, even if I could find discussions about Python/SqlAlchemy integration, I could not make it work. I installed python-monetdb module and have a running monetdb server. Now I expect my client application to work with monetdb as it does with postgresql and instead of passing a connection string like: postgres://user:password@somehost:port/db I use: monetdb://user:password@somehost/db But I get this error: ArgumentError: Could not determine dialect for 'monetdb'. What are the steps required to integrate monetdb into SqlAlchemy? Certainly missing the obvious but I'm currently stuck. Thank you in advance for any help, Stephane.

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Re: [MonetDB-users] Strange things...
by Alexey Mints 07 May '12

07 May '12

Dear All! My old problem http://sourceforge.net/mailarchive/message.php?msg_id=29168305 strikes back on the new version. The situation is just the same - combination of two conditions gives empty result (that is wrong), while each condition alone gives correct resultset. The problem shows up only in the SECOND run of quite a huge set of queries (the first one runs Ok). Even more, there has to be some delay (~10 sec) before the second run, otherwise everything works. Deleting all records does not help, problem disappears only if I recreate the table. What on Earth can this be? It seems rather hard to pin down the problem with SQL-methods only. Just in case - I attach traces of correct and incorrect queries. Regards, Alexey Mints

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[MonetDB-users] problem after upgrading (probably)
by Gijs Molenaar 04 May '12

04 May '12

Hi MonetDB people, greetings from the other side of the street. Long time no see. I just upgraded my monetdb installation to the April release. I use the Ubuntu repo. my database is running, but when I try to connect with the Python API or mclient I get the error: CREATE AGGREGATE: name 'median' (tinyint(8)) already in use Any suggestion how to figure out how to solve this problem? greetings, -- Gijs Molenaar http://www.astro.uva.nl/people/gijs-molenaar/

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[MonetDB-users] bug tracker problems?
by Gijs Molenaar 04 May '12

04 May '12

Me again, I have some issues with the ubuntu packages that I would like to report, but I can't get access to the bug tracker. First of all, the machines seems to respond not really fast. But when I open a new account after the token verification the webserver gives an empty response (according to my browser). I tried this a couple of times now. Is it me? -- Gijs Molenaar http://www.astro.uva.nl/people/gijs-molenaar/

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[MonetDB-users] MonetDB clustering
by Maik Strewe 03 May '12

03 May '12

Hi and good morning from Germany. My name is Maik Strewe and I want to test the performance of the monetDB in a cluster. My application needs millions of rows but few columns. I have to set up an monetDB cluster on 2 servers at an external server hoster. The single instances on the hosts are installed and running. Then I tried to use the "monetdb discover" command but the servers cant see each other. As far as I know the discovery is based on a UDP broadcast, right? Is it possible to configure the cluster members in a configuration file so that the monetdb instance can discover the cluster member by configuration?

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[MonetDB-users] MonetDB clustering
by Maik Strewe 03 May '12

03 May '12

Hi and good morning from Germany. My name is Maik Strewe and I want to test the performance of the monetDB in a cluster. My application needs millions of rows but few columns. I have to set up an monetDB cluster on 2 servers at an external server hoster. The single instances on the hosts are installed and running. Then I tried to use the "monetdb discover" command but the servers cant see each other. As far as I know the discovery is based on a UDP broadcast, right? Is it possible to configure the cluster members in a configuration file so that the monetdb instance can discover the cluster member by configuration?

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Re: [MonetDB-users] Strange things...
by Alexey Mints 02 May '12

02 May '12

Problem solved itself (for now) with the upgrade to the latest version.

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[MonetDB-users] Selecting cracker update algorithms
by Stef Sijben 02 May '12

02 May '12

Hello, We are a group of students trying to repeat the experiments described in the paper Updating a Cracked Database [1]. We know how to use the cracking optimizer, but what we can't figure out is how to select one of the described algorithms to be used for updates. We found implementations of all the algorithms in the source code and I have been looking in documentation and the source code for a considerable time without any luck. Can someone please point us in the right direction? Thanks, Stef Sijben References [1] S. Idreos, M.L. Kersten, and S. Manegold. Updating a cracked database. In Proceedings of the 2007 ACM SIGMOD international conference on Management of data, pages 413–424. ACM, 2007.

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