- users-list - monetdb.org

MonetDB Cluster Management
by Ali Salem 05 Sep '14

05 Sep '14

Hello all, I followed the tutorial on https://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/ClusterManagement but I still can't get it to work. I followed all instructions, but *monetdb discover *only returns instance(s) running on the same machine, but not others on the network. I am using three machines running debian, with monetdb installed and configured according to the link above. What am I missing? Your assistance is highly appreciated.

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Messed up MonetDB installation? SQL module not initialized
by Steffen B 05 Sep '14

05 Sep '14

Hello, because of some library stuff I had to reinstall MonetDB on my Linux Mint/Ubuntu maschine. I removed all Packages that had anything to do with monetdb and did a fresh sudo apt-get install monetdb5-sql monetdb-client But now when I start mclient -l mal the SQL-module seems to be broken. I can do a sql.init(); without any errors but when I do t := sql.mvc(); I get: MAPI = (monetdb) /tmp/.s.monetdb.50000 QUERY = t := sql.mvc(); ERROR = !SQLException:mvc:SQL module not initialized Please tell me which additional information you need to help me. Thank you very much Steffen

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JDBC driver problem - rounding decimal numbers during binding
by Radovan Bičiště 04 Sep '14

04 Sep '14

Hello, Today I discovered problem in JDBC driver that caused a very ugly problem with rounding decimal numbers. It rounds decimal numbers during binding. I encountered the bug with the latest driver from Jan2014-SP3 distribution. I filed bug 3561 in MonetDB bug system. Regards, Radovan

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Available binary functions
by Dennis Pallett 02 Sep '14

02 Sep '14

Hi all, I'm just wondering what kind of binary functions MonetDB comes with standard? I'm specifically looking for a function to convert a smallint/int/bigint into a byte array (either big or little endian), concat several byte arrays into a single byte array and encode a byte array as a hex string. Do any such functions exist or do I need to write them myself in C? Best regards, Dennis Pallett

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Costly bat.new/bat.append not optimized out
by Frédéric Jolliton 28 Aug '14

28 Aug '14

Hi, Unless I'm missing something, I do not understand why this apparent pattern is not easily optimized out: X_3:bat[:oid,:lng] =<tmp_321264>[0] := bat.new(nil:oid,nil:lng); .. # X_3 is never used before this line. X_19=<tmp_331015>[23068647] := <some computation> X_20=<tmp_321264>[23068647] := bat.append(X_3=<tmp_321264>:bat[:oid,:lng][23068647], X_19=<tmp_331015>[23068647],true); # X_3 is never used after this line. An empty BAT is created for the sole purpose of appending a BAT with millions of rows, discarding the original one.. instead of just using it! This account for up to 30% of the time spent for some SQL queries! Like this one: SELECT name, avg(value) FROM some_view GROUP BY name LIMIT 10; I tried to manually remove these extra operation, and I got the exact same result, in less time. (I took the output of EXPLAIN, removed the lines in question, and added a bit of type information for the function to compile, before playing it in mclient -l mal.) Regarding the setup, for our tests, we have 3 tables (say, a, b and c) of 11M rows each, then a view declared as: CREATE VIEW some_view AS (SELECT * FROM a UNION ALL SELECT * FROM b UNION ALL SELECT * FROM c); I've tested it with v11.17.21 and v11.19.0, with the "default" optimizer. My question: is this extra operation required, or could it be optimized in MonetDB? -- Frédéric Jolliton SecurActive

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ODBC driver and config on the Mac?
by Robert Kosara 19 Aug '14

19 Aug '14

Hello, I’ve been trying to connect to MonetDB via ODBC on Mac OS X, without luck. I’m seeing the ODBC drivers in /usr/local/monetdb/lib/, but I’m confused that they are .so files and not .dylib. It looks like all the others are .dylib, and as far as I know that’s required so they can be loaded dynamically. I’ve tried using the .so files in the ODBC manager, but that has only made it crash. Has anybody used MonetDB with ODBC on the Mac? Can you perhaps show me your configuration? Thanks, Robert

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Table is not unique, corrupt catalog?
by Ali Salem 11 Aug '14

11 Aug '14

Hello all, Last night I imported 500M records into my fact table, it took around 19 hours, but it worked fine. I created my indexes afterwards with no issues as well. However, when I tried to access the rest of the tables in my database, I received the following error: table table_name is not unique, corrupt catalog? Any idea why this happened and how to fix it? Thank you.

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MonetDB partition by day
by Ali Salem 08 Aug '14

08 Aug '14

Hello all, I know MonetDB has window functions, but can I partition a table by day? If you can direct me to a link with examples, I'd appreciate it. Thanks

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MEDIAN(double) not found
by Radovan Bičiště 08 Aug '14

08 Aug '14

Hello, We use MonetDB Jan2014-SP2. When I try MEDIAN function it simply says: MEDIAN: no such operator 'median(double)' [SQL State=22000] Am I missing something? I tried to execute section of 39_analytics.sql containing the MEDIAN function. It says MEDIAN function is already there. Thank you for any tips. Radovan Test Case: I took the sql from bug 2454: select median(id) from sys.tables; result: An error occurred when executing the SQL command: select median(id) from sys.tables MEDIAN: no such operator 'median(int)' [SQL State=22000] Execution time: 0.03s 1 statement failed.

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Connection Reset(mserver still alive?)
by Ali Salem 06 Aug '14

06 Aug '14

Hello, I have recently started using MonetDB for a BI project, and it's doing pretty well. However, I receive a connection reset error each time I run an ETL process (I use Pentaho PDI) to populate my dimensional schema. This error is reported by the MonetDB JDBC driver *Connection reset(mserver still alive?)* This usually happens after a random amount of time, 30 min, 45 min, 1 hour, etc. Any pointers related to this would be very helpful. Specs ------- Ubuntu 12.04 8 GB Ram 500 GB Space Pentaho PDI (community edition) Monetdb5 (installed using apt-get) Thank you.

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