users-list August 2005

users-list@monetdb.org

12 participants
13 discussions

by Henk van Lingen

Hi, Is there a special reason there are no i686 RPM's anymore like there were until 4.6.0_rc2? I think it's a bit weird there are RPM's for the hobby OS 'FedoraCore' but not for the much used server OS 'RedHat Enterprise 3 (and 4)'? The FedoraCore (which Core?) needs libstdc++.so.6 whereas RHEL 3 only has libstdc++.so.5 ... There also seems to be no SRPM's. Cheers, -- Henk van Lingen, Systems & Network Administrator (o- -+ Dept. of Computer Science, Utrecht University. /\ | phone: +31-30-2535278 v_/_ http://henk.vanlingen.net/ http://www.tuxtown.net/netiquette/

16 years, 3 months

[MonetDB-users] "Large" document collection and MonetDB/XQuery

by Bastiaan Naber

We have been experimenting with the MonetDB/XQuery at our institure and we have some issues. We have loaded 727 XML documents into MonetDB with the shred_doc() command: shred_doc("{xml file 1}, "1") shred_doc("{xml file 2}, "2") etc... These files are small (4 a 5 kilobytes). When we query these files with the following query the result takes a long time to complete (2 minutes): for $i in ("0", "1", .... "727") return $i Can anyone explain why looping over 727 documents is so slow? We have collected all 727 XML documents into 1 XML file and loaded this in MonetDB and this is a lot faster. The test machine is a 2.8 GHz P4 with 1 GB of memory. Another isue is related to the size of the database on the harddisk. When we fist load the 727 XML documents into the database the database directory contains about 47.000 files and is 50 megabytes in size. When we have excuted a number of querys the size of this directory increases to 1.7 gigabytes!! Can anyone explain this behaviour? Is MonetDB generating somekind of dynamic indices? Thanks for your replys, Bastiaan Naber

16 years, 10 months

[MonetDB-users] MonetDB/XQuery: performance issues

by Peter van der Kamp

I've been experimenting with MonetDB/XQuery for some time now and i wonder what kind of machine was used to produce the benchmark results as published on the website. Are there some guidelines ("do's and don'ts") with respect to performance? Peter van der Kamp

16 years, 11 months

[MonetDB-users] AMD64 version of MonetDB for Windows?

by Cardillo Raymond A Civ AFRL/IFEA

Has anyone out there taken the time to build an MSI for the AMD64 versions of Windows? The x64 version of Windows was released a few months ago and was available in Beta for a while, so I'm hoping someone has either done this already, or can provide some advice on how to build/compile for this platform. Anyone know of future plans to make this one of the standard platform builds? Windows x64 is only going to grow in popularity from here, especially amongst researchers and others who can benefit from 64 bits. Thanks for any info, Ray Cardillo

16 years, 11 months

[MonetDB-users] Perl and MonetDB Xquery

by Peter van der Kamp

LS, As Perl is one of the main programming languages at our institute, I tried the Perl API with MonetDB-Xquery. I succeeded with sending mil statements (with the language parameter set to 'mil') to the server and getting the correct answer, but xqueries failed (with the language parameter set to 'xquery'). This was not a complete surprise as the documentation seems to be ambiguous ("MonetDB/XQuery for POSIX (Linux/Unix) platforms currently only supports MAPI (MonetDB API) to communicate with the XQuery engine."). Following the link to the API's: "Perl binding of the simple Monet API (Mapi) for MIL/SQL database interaction". So, I would like to know if my assumption that currently no xqueries are supported by the Perl API is correct. Peter

16 years, 11 months

[MonetDB-users] BerkeleyDB

by Rodrigo Schmidt

Has anyone compared the relative performance between MonetDB (MIL interface) and BerkeleyDB? If so, what were the results? Cheers, Rodrigo

16 years, 11 months

[MonetDB-users] Re: Support for group by <ordinal> and SQL OLAP functions

by Fabian (MonetDB Project)

(I'm sending this to the monetdb-users list, as it might help some other people too) Hi, Thanks for your interest in MonetDB/SQL. gustavo wrote: > ... What I´m missing mostly is support for group by a > number of a column. In this way it would be possible to group by na > expression without the use of a derived table (select from select). I don't exactly understand what you want to do. Can you give a concrete (SQL) example that shows what you want to do? I think that would help getting me to understand. > Another > thing that could boost MonetDb usage is SQL OLAP support like stddev, ranks, > running sums/averages, windowing support, rollup and cube. Most of what you mention require a different approach to the data I think. Like running sums or windowing support somehow require you to examine 'streams' of data, thus acting on data as soon as it comes in. I don't think SQL is yet up for this job, the best you can do is simply simulate it. I think CUBE was added to SQL-2003 and therefore might get included, but I don't think on the short term. However, a concrete list of wishes is always welcome! Thanks for your input!

16 years, 11 months

[MonetDB-users] JDBC driver

by Rodrigo Schmidt

I installed MonetDB_JDBC-1.2-Blunt-SR1.jar and I am getting the following problem when I try to load MonetDriver using class.forName(): java.lang.UnsupportedClassVersionError: nl/cwi/monetdb/jdbc/MonetDriver (Unsupported major.minor version 49.0). Does any of you know what the problem is? Cheers, Rodrigo

16 years, 11 months

[MonetDB-users] Problem configuring MonetDB/XQuery

by Peter van der Kamp

I successfully build MonetDB, prior to configure and build the XQuery front end. However, running configure for this front end stops with: Checking for Mx... no configure: error: No Mx found in PATH I try to build the Mx software, without success. Before continuing I would like to know if the XQuery front end really needs Mx. Thanks. Peter van der Kamp

16 years, 11 months

[MonetDB-users] inconsistent database

by Rodrigo Schmidt

Hi, While playing with SQL schemas (creating and eliminating them) I managed to put the database in an inconsistent state. Now I have a schema with nothing inside (neither users nor tables) and apparently I am not able to drop it. When I try, both database server and client crash with an internal error. Is there any monetdb tool that checks the database consistency and recovers it if a problem is identified? Cheers, Rodrigo

16 years, 11 months

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users-list August 2005