- users-list - monetdb.org

[MonetDB-users] Fwd: wkb representation of a geometry
by Georgios Garmpis 04 May '11

04 May '11

Hi, I need to get the Well Known Binary representation of a geometry but I didn't find any function in documentation to do this. Any ideas? -- George Garbis

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[MonetDB-users] How does MonetDB work
by anjenny 04 May '11

04 May '11

Hey, my name is anjenny and im doin a little research on MonetDB for a project. My Question is How does MonetDB actually work? Greetings anjenny -- View this message in context: http://old.nabble.com/How-does-MonetDB-work-tp31440282p31440282.html Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] Time Interval Overlap
by brien colwell 29 Apr '11

29 Apr '11

Hi all, I have a table that stores a time interval as two timestamps, and want to construct the most efficient query to check whether two intervals in the table overlap. The naive way, using two range conditions [1], seems to choke for large tables. The M5 SQL manual mentions an OVERLAPS operator that, as far as I've read [2], seems to use an optimized interval join algorithm. Can anyone clarify: 1. How to convert a start timestamp and an end timestamp into an interval type 2. How to use the OVERLAPS operator Many thanks. Brien [0] create table intervals as ( id bigint, series_id bigint, start_time timestamp, end_time timestamp ) [1] select a.id as a_id b.id as b_id from intervals a inner join intervals b on b.series_id = a.series_id and b.id < a.id and b.start_time < a.end_time and a.start_time < b.end_time [2] http://monetdb.cwi.nl/XQuery/Documentation/StandOff-Extension.html

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[MonetDB-users] rowcount in monetdb
by Vassilis Papakonstantinou 29 Apr '11

29 Apr '11

Hello all, Is there a way to take the number of rows affected by the last statement just like @@ROWCOUNT in SQL Server or SQL%ROWCOUNT in Oracle? Thanks, Vassilis

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Re: [MonetDB-users] Discontinuation of MonetDB XQuery
by Peter Boncz 29 Apr '11

29 Apr '11

Hi Ryad, There have been plans to port XQuery to MonetDB5, but there has been lack of time and manpower to make this possible. This shortage of resources might change if the database research community regains interest in XQuery in a future. At CWI, a research project, engineering effort must always be justified by ongoing research projects that profit from it. For the moment, it is hard to predict when there will be XML database research projects again, but I would not rule it out. For the moment, you can also just continue to use MonetDB/XQuery. It had not changed much anyway in the past two years, so the change is not dramatic. The software is still available in open source in this April branch of the MonetDB software. So one can still download it in binary, check out the source, change it, compile it and even redistribute it according to the license. CWI for the moment just will not create new releases for it. Peter From: Ryad Ben-El-Kezadri [mailto:ryad.bek@gmail.com] Sent: Friday, April 29, 2011 9:49 AM To: monetdb-users(a)lists.sourceforge.net Subject: [MonetDB-users] Discontinuation of MonetDB XQuery Hello I am a MonetDB XQuery supporter (http://permalink.gmane.org/gmane.comp.db.monetdb.user/3824) and I am sad that it is discontinued. I was very enthusiastic about the software so I was rather excepting an upgrade to MonetDB5. However I am confident that it will be easy to turn my application to MonetDB5. As a basic XQuery user, my questions are threefold: 1)Are there some explanations for this change (flaws in the design of XQuery 2.0, lack of users, performance limitation)? 2)Is MonetDB5 SQL able to store GB of data (as MonetDB XQuery)? Will we observe performance gains for (time ordered) one dimensional data? 3)Is there an equivalent to the XRPC API? Warm regards Ryad

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[MonetDB-users] Discontinuation of MonetDB XQuery
by Ryad Ben-El-Kezadri 29 Apr '11

29 Apr '11

Hello I am a MonetDB XQuery supporter ( http://permalink.gmane.org/gmane.comp.db.monetdb.user/3824) and I am sad that it is discontinued. I was very enthusiastic about the software so I was rather excepting an upgrade to MonetDB5. However I am confident that it will be easy to turn my application to MonetDB5. As a basic XQuery user, my questions are threefold: 1)Are there some explanations for this change (flaws in the design of XQuery 2.0, lack of users, performance limitation)? 2)Is MonetDB5 SQL able to store GB of data (as MonetDB XQuery)? Will we observe performance gains for (time ordered) one dimensional data? 3)Is there an equivalent to the XRPC API? Warm regards Ryad

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[MonetDB-users] Announcement: New Apr2011 feature release of MonetDB suite
by Sjoerd Mullender 28 Apr '11

28 Apr '11

The MonetDB team at CWI/MonetDB BV is pleased to announce the Apr2011 feature release of the MonetDB suite of programs. As announced one month ago to the day (March 28, 2011), this release marks the start of a new era: development of MonetDB4 and MonetDB/XQuery has ceased. Development of the Pathfinder compiler continues unabated at the University of Tübingen [1], but there is no longer a link being maintained with MonetDB. For details on this release, please see the release notes at <http://monetdb.cwi.nl/Development/Releases/Apr2011/>. [1] http://www.pathfinder-xquery.org/ -- Sjoerd Mullender

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[MonetDB-users] invisible join in Monetdb
by Souman Mandal 26 Apr '11

26 Apr '11

Hi, I am a M-tech student at IIT Bombay. Currently I am doing a project to compare the performance of a column store database with implementation of invisible join and without implementation of invisible join. Now I want to use MonetDB for my project. But I have couple of doubts: > Does invisible join is already implemented in MonetDB? > Where can I get the documentation of the source code? > Though I am running mserver5 process, still if I try to execute the command 'monetdb create test' I am getting a error "monetdb: cannot perform: MonetDB Database Server (merovingian) is not running". How to solve this problem. I really need some help. Waiting for some reply. Thanks & Regards, Souman Mandal

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[MonetDB-users] values of type char(n) not always blank padded?
by Ying Zhang 24 Apr '11

24 Apr '11

Hi, I'm wondering if the following results of querying values of the type char(n) (here n = 50), is expected or an error, since char(n) defines a fixed-length, blank padded string: sql>create table a2 (c1 char(5), c2 char(50)); operation successful sql>insert into a2 values ('abc', 'abc'), ('defg', 'defg'); 2 affected rows (2.848ms) sql>select c1, c2 from a2; +-------+----------------------------------------------------+ | c1 | c2 | +=======+====================================================+ | abc | abc | | defg | defg | +-------+----------------------------------------------------+ 2 tuples (1.655ms) sql>select '#' || c1 || '#' || c2 || '#' from a2; +------------------------------------------------------------+ | concat_single_value | +============================================================+ | #abc#abc# | | #defg#defg# | +------------------------------------------------------------+ 2 tuples (2.242ms) LQL The result of the first SELECT shows that c1 and c2 are blank padded (according to the SQL standard). The result of the second SELECT looks a bit strange, are the padding space characters removed or added after the last '#'? Is this the expected result or an error? Thanks, Jennie

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[MonetDB-users] Using COPY with php_mapi and php_monetdb.php
by Henning Grosch 15 Apr '11

15 Apr '11

Hi, at the moment I use the odbc_drive to connect to my monetdb database. In one script I use COPY to get lots of data in my database. Everything works fine. Yesterday is downloaded the latest source files. There I found the php_mapi.inc and the php_monetdb.php with these two files I can now use monetdb in php without odbc. Now I am trying to use COPY and what happens is I get an error that the remote address canceled the socket connection. This only seems to happen with copy anything else works as excpected. So is it possible to use copy with a socket connection? Thanks. Henning

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