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Table partitioning over nodes
by Jiří Nádvorník 31 Mar '15

31 Mar '15

Hi All, I have one table with data that can be grouped easily. I need to iterate over these groups, count their members and distribute them uniformly over the database nodes (physically). If I have three groups A, B, C of size (1, 1, 2) and two physical nodes - I want A,B to be on node no. 1 and C on the node no. 2. The question is quite simple. Is it possible? Jiri Nadvornik Astronomical Institute AV CR Stellar department Czech Republic <mailto:nadvornik.ji@gmail.com> nadvornik.ji(a)gmail.com

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COPY INTO FROM STDIN and auto increment column
by fadila.mumbasic＠uniserv.com 30 Mar '15

30 Mar '15

Hi, We are facing problems with COPY INTO .. FROM STDIN and an auto increment column, which is the primary key column in the table. The client is our own java client. If we don't set any value for this column (which is our expected constellation) there is neither error nor exception, but no record is inserted into the table. A try with a null value for this column produces the same result (no exception, no record in the table) The only way to insert records is to set the proper value for the column, but it is not the supposed behavior of an auto increment column, isn't it? Best regards, Fadila

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SQL string from PreparedStatement ??
by Vijay Krishna 30 Mar '15

30 Mar '15

Hi, Is there any way to get the SQL query as a string from the PreparedStatement of MonetDB?? (Like in some DBs, toString will give the SQL string) Any help much appreciated. Thanks in advance. Thanks & Regards, Vijayakrishna.P. Mobile : (+91) 9500402305.

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Count function with Over clause()
by Amey M 30 Mar '15

30 Mar '15

The Aggregate count function doesn't work with the over clause in MonetDB. I am a new user on MonetDB, and have trouble using queries running on other databases like Postgres on MonetDB. When using the Count function with Over clause I get the following error: sql>select count(id) over() from sample_table ;SELECT: function 'count' not found Regards, Ameya

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MonetDB C functions
by Jiří Nádvorník 29 Mar '15

29 Mar '15

Hi all, I'm trying to understand the example of user defined functions in MonetDB (https://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/UserDefinedFunct ion). I understand the concept for just reversing a string. But what about working with tabular data? I'd like to pass to this C function a whole table (list of rows) and then return another table(s)/write result data to other tables. What is the correct way of doing this? Can I pass some kind of arrays to the C function? Can I return these arrays from a function? Or is it possible to query the DB directly from the C script? Thank you very much for some answers. Best regards, Jiri Nadvornik Astronomical Institute AV CR Stellar department Czech Republic <mailto:nadvornik.ji@gmail.com> nadvornik.ji(a)gmail.com

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Better understand those MAL functions
by Leon-Constantin Fopa 29 Mar '15

29 Mar '15

hello dear all, I'm trying to understand an execution plan generated in MAL by monetDB. I would like to how exactlly the following functions works : - sql.mvc - algebra.subselect - sql.bind - sql.subdelta - algebra.leftfetchjoin Best regards,

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Arrays in MonetDB
by Jiří Nádvorník 27 Mar '15

27 Mar '15

Hi, Do I understand correctly that MonetDB does not support array types? What's the best possibility to use instead of them? I have a table of pixels and table of points. For each pixel.ID I have two different arrays of points to store in the DB. Thank you for clarification. Best regards, Jiri Nadvornik Astronomical Institute AV CR Stellar department Czech Republic <mailto:nadvornik.ji@gmail.com> nadvornik.ji(a)gmail.com

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MonetDB user defined function grouping
by Jiří Nádvorník 26 Mar '15

26 Mar '15

Hi all, I am trying to do a user defined function written in C++ which takes the whole table as a parameter, loads it into a vector structure, and then divides the data in some groups (duplicities will occur). How can I return the results of this grouping from the C function? Probably I'd like to store the group IDs in a separate table and create and then create an M:N table between the group IDs and the original records. Any help appreciated. Best regards, Jiri Nadvornik Astronomical Institute AV CR Stellar department Czech Republic <mailto:nadvornik.ji@gmail.com> nadvornik.ji(a)gmail.com

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HEALPix with monetDB
by Jiří Nádvorník 25 Mar '15

25 Mar '15

Hi all, I'm planning to index my spherical data in MonetDB byHEALPix. I will need it for: 1. Data partitioning - distribute the data uniformly on the DB nodes, but keep them sorted (keep points close on the sphere on the same node). 2. Neighbor lookup - can I actually index my spherical coordinates stored in MonetDB by some kind of a BTree of HEALPix pixels? I understand how computing a hash for the coordinates and indexing on it helps in relational DB, but how do the indices function in an array DB like MonetDB? I'd like to benefit from the array storage of the data, because I will often look for nearest neighbors and compute distances between these neighbors. I will also divide the data in the beginning for parallel tasks by some calculation of their pixels, but that will be done only once in the beginning, the main computation will be around clustering these objects, which means lots and lots of neighbor searches and distance computation. Has somebody already tried to use HEALPix, or some other spherical index in MonetDB? How can I control the distribution of data across the nodes (e.g. sort them by this index)? How can I use and benefit from this kind of indexing in MonetDB? Thank you very much for even some questions answered. Best regards, Jiri Nadvornik Astronomical Institute AV CR Stellar department Czech Republic nadvornik.ji(a)gmail.com

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Case insensitive LIKE ??
by Vijay Krishna 23 Mar '15

23 Mar '15

Hi, By default the LIKE criteria of MonetDB returns results by matching the exact case of the search word (MonetDB Jan 2014 SP1 Mac). How to make the LIKE criteria to do a case insensitive search by default?? (Something like the BINARY keyword that does case sensitive search in MySQL??) I don't wish to add a workaround like "LOWER(column) like LOWER(searchword)" here.. Any help much appreciated. Thanks in advance. Thanks & Regards, Vijayakrishna.P. Mobile : (+91) 9500402305.

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