- users-list - monetdb.org

[MonetDB-users] strange decrease in performance after some deletes
by Majid Azimi 25 Jun '12

25 Jun '12

Hi guys, I have loaded 80 million records in database. a very complex aggregate query(multiple COUNT, SUM, AVG, GROUP BY combined) runs deadly fast in about 30 seconds. But after deleting 700 records performance has been decreased alot. the same query runs in 8 minutes now. Is this usual? Thank you

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[MonetDB-users] Changing SysV parameteres
by Majid Azimi 19 Jun '12

19 Jun '12

Hi guys, Does changing SysV parameters such as SHMMAX, SHMMIN, SHMSEG , ... affects MonetDB performance? How they affect? I mean the vanilla installation of MonetDB on a very powerful hardware needs massive optimization like what we see on other relational DBMS products?

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[MonetDB-users] Announcement: New Apr2012-SP2 Bugfix release of MonetDB suite
by Sjoerd Mullender 19 Jun '12

19 Jun '12

The MonetDB team at CWI/MonetDB BV is pleased to announce the Apr2012-SP2 bugfix release of the MonetDB suite of programs. More information about MonetDB can be found on our website at <http://www.monetdb.org/>. For details on this release, please see the release notes at <http://www.monetdb.org/Downloads/ReleaseNotes>. As usual, the download location is <http://dev.monetdb.org/downloads/>. Apr 2012-SP2 bugfix release Client Package * Resolved a cosmetical error where tab-characters would cause misalignments in tabular result views. For the time being, tabs are now represented as a single space in tabular view. MonetDB Common * Limit number of detected CPU cores to 16 on 32-bits systems to avoid running quickly out of addressable resources followed by a kill from the OS. Bug Fixes * 2594: NULL cannot automatically be casted to every other type * 3085: assertion fails upon execution of a valid SQL query * 3086: Modulo function does not work in select from table * 3087: query causes "Not yet implemented" message * 3089: mserver5 crashed if join condition has two column and incorrect order * 3090: crashed if using single identifier for where condition * 3096: Type of median error

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Re: [MonetDB-users] python-monetdb and pip
by Alexey Mints 18 Jun '12

18 Jun '12

Hallo! As far as Python question has been raised. There is a tiny thing that is (probably) missing in the client. Connection class (and other classes as well) are not inherited from the "object" class, therefore further inheritance and method overriding is problematic. I think, this might be corrected in future. Regards, Alexey Mints

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[MonetDB-users] Locality Sensitive Hashing method for Image Retrieval
by BOOM Bas 18 Jun '12

18 Jun '12

Hi, Sorry, I am new to this mailinglist and not sure this question fits, but have I question how to optimize my queries I am experimenting with monetdb for image retrieval, having an image database of 300000 image. At the moment, I am using the Locality Sensitive Hashing method and because I understood from the monetdb documenation that monetdb supports indexing/hash tables, which makes the implementation quiet easy in monetdb. I have for each image 30 buckets with 24 bit strings (int) (should be indexed, assume automatically done by monetdb) I have for each image a feature vector of 1000 real values. I have for each image a unique id together with some info like file name. At the moment, my table is as follows image_id, filename, bucket_1, bucket_2, bucket_3 ... bucket_30, feature_value_1, feature_value_2, ..., feature_value_1000 For Locality Sensitive Hashing, I am performing the following sql query: select * from table where bucket_1 = bitstring or bucket_2 = bitstring or bucket_3 = bitstring or ... bucket_30 = bitstring (limit 1000) These bitstrings are quiet unique, giving me around the 500 images from the entire database. I would also like to obtain the feature vector (so all feature values). At the moment, query and data retrieval times depends but often take around 0.5-1 minute, what are ways to improve this. Does using 2 tables help or storing the feature vector in one column? Ideas are welcome. I am using the MAPI client to retrieve the data. Happy to provide more information if necessary Cheers, Bas Boom University of Edinburgh part of Fish4Knowledge consortium -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

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[MonetDB-users] charset problem with the odbc driver for windows
by liangmeng 18 Jun '12

18 Jun '12

hello, all, i installed monetdb in windows server 2008(64bit) , and installed the odbc for windows( 32bit intalled firstly, and 64bit the next), after insert some Chinese characters, i use oracle biee to show the table data, but biee can't show all the characters, just like below: 1��monetdb data showed in biee i also install mysql to test this, the database character set is utf8 too, and biee can show the data correctly: 2��mysql data showed in biee the data showed in command line tool are the same from monetdb and mysql monetdb command line tool return: sql>select * from test2; +------+ | nam | +======+ | 广州 | | 梅州 | +------+ 2 tuples (2.189ms) mysql commad line tool return: mysql> select * from test; +--------+ | nam | +--------+ | 广州 | | 梅州 | +--------+ 2 rows in set (0.00 sec) Does this mean that: the odbc driver of monetdb has some problems?

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[MonetDB-users] monetdb--query is very slow on table about 1 billion rows
by liangmeng 16 Jun '12

16 Jun '12

hi, guys, i create a simple table , and the table is up to 1 billion rows, its structure as follow: create table test(Month_ID int not null, C_NAME varchar(10) not null, C_ID int not null, MSISDN varchar(15) not null, C_FLUX double not null); and the data looks like: “201201，name1, 123213, 13723213213, 12.12321" when i execute the query "select c_name,c_flux from test where c_id=**** order by c_flux desc", it takes more than 3 minute to get the result(more than 100 thousands rows returned, if limit 100 is used, the execute time is about 40s), is there any ways to optimize? Hardwares: intel xeon 2.12*8, 32G memory, 4*1T SATA(raid 0)

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[MonetDB-users] How to see what query is running? kill long running queries?
by Majid Azimi 15 Jun '12

15 Jun '12

Hi guys, Is it possible to see what queries are running on the database? How to kill a query? I have a issued a SELECT * query and then looked at sys.querylog and sys.queryhistory, But they are empty. Is there any solution?

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[MonetDB-users] RDF3x to MonetDB
by Hancel Gonzalez 15 Jun '12

15 Jun '12

Hi people, i have installed rdf-3x <http://www.mpi-inf.mpg.de/~neumann/rdf3x/>. This software have *buildmonetdb *that is for translate rdf queries to monetdb. The problem is that i dont know which arguments i have send in command line. I appreciate your help! Greettings, Hancel Gonzalez.

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[MonetDB-users] monetdb do not release the memory
by liangmeng 15 Jun '12

15 Jun '12

hi, everyone i'am new here, i install monetdb of windows 64bit version, after copy into table from several very large files(about 10G each), i found that monetdb occupied too much momery, almost 100% of total 32G , and it keeps occupying, after 24hours, it still don't release the memory, what's the matter? Also, i found the same problem after query several times with large amount of records returned;

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