October 2015 - users-list

Re: users-list Digest, Vol 38, Issue 9
by Luciano Sasso 18 Oct '15

18 Oct '15

Im Jul 2015, remote tables can sort in result query ? At --- Este email foi escaneado pelo Avast antivírus. https://www.avast.com/antivirus

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MonetDB scripting
by Doug Service 18 Oct '15

18 Oct '15

Hello Everyone, I need to become more conversant in monetdb scripting and have read the pages on functions and procedures on the website. However, more examples would be very helpful. Does anyone know of a good repository of extensive monetdb scripts that provide good models. Doug Service

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Concurrent Transaction control in MonetDB
by Vijay Krishna 18 Oct '15

18 Oct '15

Hi, I read the following lines in a thesis on MonetDB titled - "Improving Transactional Stability in MonetDB" where in they had explained the concurrency control in MonetDB as "Concurrent updates (writers) are not anticipated and in case of N con􏰃icting transactions, only one of them (the one having the earliest time-stamp) is guaranteed to eventually commit its changes. Concurrent appends (on the same table) are detected as write-to-write conflicts and only the writer carrying the earliest … [View More]

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Plan for feature, external REMOTE table as a plugin (hadoop, jdbc, odbc, etc).
by Aris Setyawan 17 Oct '15

17 Oct '15

Hi, The key value of monetdb is it's parallel query. That many other opensource DBMS doesn't support it. But monetdb have it in the core engine. It is mean a mature feature. Having ability load (on the fly) any other DBMS data using external REMOTE table, and then query them using monetdb parallel query, will attract big community and contribution (as a plugin). The dbms, for example: jdbc, odbc, mysql, postgresql, hadoop, hive, or any commercial dbms. Any dbms which doesn't have parallel … [View More]

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SQL join involving remote table.
by Aris Setyawan 17 Oct '15

17 Oct '15

Hi, According to https://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/DistributedQuery… It is said that, "Queries involving remote tables are automatically split into subqueries by the master database and executed on remote databases.". I think this scenario: I have 3 server, one master server and two worker servers. I have 2 tables, A (big one, a fact table) and B (small one, a dimension table). A is a merge table of 2 remote tables. The remote table exist in two worker servers. B is … [View More]

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JDBC Connection to a schema
by Vijay Krishna 16 Oct '15

16 Oct '15

Hi, I am trying to connect a schema within a database directly through JDBC with the following Java code. Connection con = DriverManager.getConnection( > "jdbc:monetdb://localhost/testUser", "monetdb", "monetdb"); > con.setSchema("schema1"); But this throws the following exception. > Exception in thread "main" java.sql.SQLException: syntax error, > unexpected '=' in: "set schema =" > at nl.cwi.monetdb.jdbc.MonetConnection$ResponseList.executeQuery( > MonetConnection.java:… [View More]

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Baseline Performance Expectation?
by Paul Ramsey 15 Oct '15

15 Oct '15

Hi all, I’ve loaded a relatively small table (I think) of 30M records, 7 columns, and I’m doing some test queries summarizing and filtering the table, like this: select vendor_id, count(*) from taxi where geohash like '90efbc6a6fc%’ group by vendor_id; On my 4-core iMac, the CPU doesn’t get very hot (20% on top, so it’s not even lighting up one of the four CPUs) , but it’s hard to tell since the return time is only 2.5 second. Is that as fast as things will get? I doubled the table size and … [View More]

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Finding the current schema
by Enzo 14 Oct '15

14 Oct '15

Is there a query that would let me know what is the current schema in my db? E.g. I would expect as a response either sys (if I haven't set any schema), or foo (if I've set the schema foo). Kindest regards Enzo enzo(a)smartinsightsfromdata.com

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Support for UUIDs in R and Python
by Doug Service 09 Oct '15

09 Oct '15

Hello everyone, I discovered this morning that the UUID type is not supported in MonetDB.R package on CRAN Error in monetdbRtype(info$types[i]) : Unknown DB type UUID and UUIDs are not support in the Python API which I installed from source File "/usr/local/lib/python3.4/dist-packages/monetdb/sql/pythonize.py", line 132, in convert raise ProgrammingError("type %s is not supported" % type_code) monetdb.exceptions.ProgrammingError: type uuid is not supported Will … [View More]

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Re UUID and new crash problem
by Doug Service 09 Oct '15

09 Oct '15

Hello Stefan, I modified the uuid.mal file in the lib directory and that all works great for a small sample test from mclient. Thanks! Now I have run into a problem where the server crashes when I try to insert into one of the tables, though inserts in other tables work fine. I do not think this problem has anything with UUIDS as the table I am inserting into does not use UUIDS and I can do inserts into tables that have uuid columns. This insert that causes the crash worked fine on the last … [View More]version of our schema that did not use UUIDs. I have a small database from msqldump and an insert statement that causes the server to crash consistently. However, I do not see any way to add attachments to a bug report on the tracker. Is there a way to do this? Is there any other information I can collect that would be useful in a bug report? Here is the monetdb log which shows a sigsegv. Doug 2015-10-06 16:02:19 MSG quantbox[3433]: # MonetDB 5 server v11.21.5 "Jul2015" 2015-10-06 16:02:19 MSG quantbox[3433]: # Serving database 'quantbox', using 4 threads 2015-10-06 16:02:19 MSG quantbox[3433]: # Compiled for x86_64-pc-linux-gnu/64bit with 64bit OIDs and 128bit integers dynamically linked 2015-10-06 16:02:19 MSG quantbox[3433]: # Found 1.907 GiB available main-memory. 2015-10-06 16:02:19 MSG quantbox[3433]: # Copyright (c) 1993-July 2008 CWI. 2015-10-06 16:02:19 MSG quantbox[3433]: # Copyright (c) August 2008-2015 MonetDB B.V., all rights reserved 2015-10-06 16:02:19 MSG quantbox[3433]: # Visit http://www.monetdb.org/ for further information 2015-10-06 16:02:19 MSG quantbox[3433]: # Listening for UNIX domain connection requests on mapi:monetdb:///var/lib/monetdb/quantbox/.mapi.sock 2015-10-06 16:02:19 MSG quantbox[3433]: # Start processing logs sql/sql_logs version 52200 2015-10-06 16:02:19 MSG quantbox[3433]: # Start reading the write-ahead log 'sql_logs/sql/log.4' 2015-10-06 16:02:19 MSG quantbox[3433]: # Finished reading the write-ahead log 'sql_logs/sql/log.4' 2015-10-06 16:02:19 MSG quantbox[3433]: # Finished processing logs sql/sql_logs 2015-10-06 16:02:19 MSG quantbox[3433]: # MonetDB/SQL module loaded 2015-10-06 16:02:19 MSG merovingian[809]: proxying client 10.1.10.101:40633 for database 'quantbox' to mapi:monetdb:///var/lib/monetdb/quantbox/.mapi.sock?database=quantbox 2015-10-06 16:02:19 MSG merovingian[809]: target connection is on local UNIX domain socket, passing on filedescriptor instead of proxying 2015-10-06 16:05:19 MSG merovingian[809]: proxying client (local) for database 'quantbox' to mapi:monetdb:///var/lib/monetdb/quantbox/.mapi.sock?database=quantbox 2015-10-06 16:05:19 MSG merovingian[809]: target connection is on local UNIX domain socket, passing on filedescriptor instead of proxying 2015-10-06 16:05:27 MSG merovingian[809]: proxying client (local) for database 'quantbox' to mapi:monetdb:///var/lib/monetdb/quantbox/.mapi.sock?database=quantbox 2015-10-06 16:05:27 MSG merovingian[809]: target connection is on local UNIX domain socket, passing on filedescriptor instead of proxying 2015-10-06 16:05:48 MSG merovingian[809]: database 'quantbox' (3433) was killed by signal SIGSEGV 2015-10-06 16:05:59 MSG merovingian[809]: starting database 'quantbox', up min/avg/max: 0s/0s/0s, crash average: 1.00 0.30 0.10 (3-0=3) 2015-10-06 16:06:00 MSG quantbox[3532]: arguments: /usr/bin/mserver5 --dbpath=/var/lib/monetdb/quantbox --set merovingian_uri=mapi:monetdb://qbdb:42000/quantbox --set mapi_open=false --set mapi_port=0 --set mapi_usock=/var/lib/monetdb/quantbox/.mapi.sock --set monet_vault_key=/var/lib/monetdb/quantbox/.vaultkey --set gdk_nr_threads=4 --set max_clients=64 --set sql_optimizer=default_pipe --set monet_daemon=yes [View Less]

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