- users-list - monetdb.org

Monetdb clusters VS Distributed Query Processing
by imad hajj chahine 22 Sep '15

22 Sep '15

Hi, I am trying to understand the main difference between clusters and the remote table introduced in JUL2015 . Correct me if I am wrong, in clusters the complete table is copied over all nodes, and monetdb will do the query parallel execution on the nodes and result concat. In the remote table I have more control on executing the query on a part of a table on a selected node depending on resources availables. If this is true, are the following point valid: 1. its better to have identical nodes for clusters 2. the execution time is inversely proportional to the number of nodes in the clusters 3. the executing time is dictated by the slowest node in cluster 4. fail-over is by default supported in cluster configuration One last question about the supported queries in these 2 modes(groupby, order, limit). if any, a reference to a documentation about the clustering is appreciated. Thank you.

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Two questions about R integration
by Roberto Cornacchia 22 Sep '15

22 Sep '15

Hi, I have 2 questions about R integration. 1) I see that missing packages are automatically installed when invoked by library() calls. That is really cool. The question: if I need a library in a function, will this actually be loaded at every function call? 2) How is a SQL type date translated to R? Apparently not "Date", because I tried to use it as such in the declared procedure and I got a complaint. I tried to figure the type myself with this: sql> create function dt(d date) returns string language R { class(d) }; sql> select dt( cast('2015-09-21' as date) ); but unfortunately this triggered a server assertion :/ mserver5: .../src/monetdb5/mal/mal_interpreter.c:648: runMALsequence: Assertion `t == stk->stk[a].vtype' failed. Thanks, Roberto

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sys.analyze not working
by Robert Koch 19 Sep '15

19 Sep '15

Following the manual https://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/statistics I am trying to reproduce this, but it fails with a type conversion error: sql>call sys.analyze('sys', 'types'); conversion of string 'sys' to type int failed. sql>SELECT * FROM sys.statistics; +-----------+------+-------+-------+--------+-------+--------+------+--------+--------+ | column_id | type | width | stamp | sample | count | unique | nils | minval | maxval |> +===========+======+=======+=======+========+=======+========+======+========+========+ +-----------+------+-------+-------+--------+-------+--------+------+--------+--------+ 0 tuples (3.013ms) !1 column dropped! Tried it with different schema/table/column names. Both with system and user-generated tables. Always the same error. Running 11.21.5 here. Thanks.

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couple of unanswered qs
by Anthony Damico 18 Sep '15

18 Sep '15

https://stackoverflow.com/questions/tagged/monetdb

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Why doesn't MonetDB exploit SIMD feature?
by Xu,Wenjian 18 Sep '15

18 Sep '15

Hi, We know that MonetDB excels in application where the database hot-set can be largely held in main-memory, since the physical operators (e.g., hashjoin, sort) are highly optimized for main-memory. But it is strange to me that these operators do not utilize SIMD which a performance-critical feature of modern CPUs. For example, MonetDB use *timsort* as its underlying stable sort algorithm (do_ssort() in gdk/gdk_ssort_impl.h), but I cannot find any SIMD instructions there. Why doesn't MonetDB exploit SIMD feature? or did I miss something? In paper 'Vectorwise: Beyond Column Stores', the authors claim that X100/Vectorwise use SIMD instructions. So my follow-up question is that whether any of X100/Vectorwise's technologies/features has been integrated into MonetDB's code base. Thank you. Best regards, Xu, Wenjian

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Encrypted Client Sessions
by James Candalino 17 Sep '15

17 Sep '15

Hi all, Is it possible to establish encrypted client sessions? If so, how? I didn't see anything in the documentation. With postgres connecting using jdbc is just jdbc:postgresql://dbhost/dbname?ssl=true. Any insight would be greatly appreciated. --James -- *NOTICE TO RECIPIENTS*: This communication is confidential and intended for the use of the addressee only. If you are not an intended recipient of this communication, please delete it immediately and notify the sender by return email. Unauthorized reading, dissemination, distribution or copying of this communication is prohibited. This communication does not constitute an offer to sell or a solicitation of an indication of interest to purchase any loan, security or any other financial product or instrument, nor is it an offer to sell or a solicitation of an indication of interest to purchase any products or services to any persons who are prohibited from receiving such information under applicable law. The contents of this communication may not be accurate or complete and are subject to change without notice. As such, Orchard App, Inc. (including its subsidiaries and affiliates, "Orchard") makes no representation regarding the accuracy or completeness of the information contained herein. The intended recipient is advised to consult its own professional advisors, including those specializing in legal, tax and accounting matters. Orchard does not provide legal, tax or accounting advice.

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Accessing admin GUI
by Peter Smith 17 Sep '15

17 Sep '15

Hi, https://www.monetdb.org/XQuery/Tutorials/adminGUI It looks as if the admin GUI should automatically start up on 50001/TCP when I start MonetDB, but this doesn't seem to be the case: I have monetdb listening on 50000, but nothing listening on 50001. I'm running MonetDB 11.19 on Ubuntu. I'm using an init.d script to start MonetDB, and here's the running process: /usr/bin/mserver5 --dbpath=/home/administrator/monetdb/xxx/xxx --set merovingian_uri mapi:monetdb://127.0.0.1:50000/xxx --set mapi_open false --set mapi_port 0 --set mapi_usock /home/administrator/monetdb/xxx/xxx/.mapi.sock --set monet_vault_key /home/administrator/monetdb/xxx/xxx/.vaultkey --set gdk_nr_threads 16 --set max_clients 64 --set sql_optimizer default_pipe --set monet_daemon yes Do I need to pass extra start-up options to enable the GUI? (I don't see anything in the mserver5 man page) Thanks, Peter Smith

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What is the difference ?
by Brian Hood 16 Sep '15

16 Sep '15

Hi All, So the new CREATE REPLICA TABLE definition / CREATE TABLE definition i'm not sure what the difference would be ? CREATE REPLICA TABLE test2 AS (SELECT * FROM test) WITH DATA; CREATE TABLE test2 AS (select * from test) WITH DATA; Regards, Brian Hood

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Inserting in 'raw' mode??
by Vijay Krishna 15 Sep '15

15 Sep '15

Hi, I was analysing the Insert performance of MonetDB... I am trying to optimize a process where in a single tuple has to be inserted into a table of 1200 columns, which takes about 7.5 seconds presently... The query has values for only 5 columns out of 1200, yet the speed is still the same.. Is it possible to reduce this time even?? While digging on this, I came across this thread.. https://www.monetdb.org/pipermail/users-list/2005-August/000139.html *What is the insert speed relatively to other DBs? > * > Using SQL, with the current version we won't compete very well. We get > much more acceptable speeds in 'raw' mode, where lots of the parsing > overhead is removed. > > Can anyone please help me understand what is the 'raw' mode that is explained in this thread?? I am using Oct-2014 version on a CentOS machine with 128 GB RAM... Thanks & Regards, Vijayakrishna.P. Mobile : (+91) 9500402305.

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DbVisualizer support for MonetDB
by Robert Koch 14 Sep '15

14 Sep '15

Hi Folks, DbVisualizer is my preferred GUI to MonetDB. DbVis offers capability to write own database profiles for specific DB's. Today I committed a MonetDB database profile for DbVisualizer. https://github.com/dbvisualizer/dbvis-database-profiles/tree/master/monetdb Anyone familiar to DbVis can import and/or improve this profile. There's a free DbVis version, but the Pro offers much more features, which make life easier. BTW, I'm not working for them. :-) Please feel free to write me your desired features by mail or directly into the MD-file inside the monetdb-directory. If possible, I will implement it inte the profile. Best regards Mario

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