April 2011 - users-list

[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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[MonetDB-users] Restore db on different platform / OID size
by Sander Kruseman 15 Apr '11

15 Apr '11

When attempting to restore a db dump, made on Windows 7 with 32 bits sized object ID's, on OSX with 64 bits sized object ID's, I run into errors. Like: CREATE FUNCTION: name 'env' already in use If I tweak the dump script by first dropping the functions that appear to exist, I get stuff like: ' from line 1 field 5 not inserted, expecting type real failed to import table Should what I try to do be possible anyway? Am I doing anything wrong? Thanks for your feedback. Sander Kruseman

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[MonetDB-users] bulk upload data
by Nic Chidu 14 Apr '11

14 Apr '11

What way do you suggest for bulk uploading data? Thanks. Nic

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[MonetDB-users] documentation on metadata statement
by Nic Chidu 13 Apr '11

13 Apr '11

Where can I find doc about metadata statements. Stuff like showing database, table, running environment. Thanks, Nic

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[MonetDB-users] Series UPDATE statements will significantly decrease server performance
by Vladimir Vlach 13 Apr '11

13 Apr '11

Hi, We are experiencing performance issue with MonetDB when running UPDATE. We have a table with 1M rows and 3.000 columns. All columns except primary_id are FLOAT type. When I execute series of these statements the performance on first 30-35 statements is quite acceptable (less then 1s) but then suddenly it gets really slow. One UPDATE takes 30 seconds or more. After next 5-10 statements the performance decreases and one UPDATE takes 1 minute or longer. We run this with AutoCommit. The behavior is very persistent. UPDATE table SET column=column+1 WHERE primary_id='e1a7d7c7204c292e56e942dbdad118d3' ; Would you say MonetDB is not suitable for bulk UPDATE operations? Thanks, Vlad

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[MonetDB-users] UPDATE INNER JOIN syntax
by Osmin Castillo 11 Apr '11

11 Apr '11

Hi guys: How can I to update a table field based on a inner join update? What's the syntax for MonetDB? thanks in advance Osmin Castillo

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