- users-list - monetdb.org

Need info about --in-memory option
by Lakshmipathy Jois 09 Apr '21

09 Apr '21

Hi All, I am new to MonetDB and this is my first email to this group. I came across the option --in-memory for mserver5. I understood that if this option is set, then MonetDB operates out of memory and data is not persisted. I wanted to know more details about the working of MonetDB if this option is set: 1. If this option is set, what is the maximum data size that MonetDB can operate with? 2. If this option is set, will MonetDB use mmap only for reading purposes or not use mmap at all? Any other information is really welcome. Thanks in advance. Lakshmi Pathy S N

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Problems installing October2020 version
by Ioannis Foufoulas 31 Mar '21

31 Mar '21

Hi, It seems that releases from October2020 have a different structure (and size) and instructions here https://www.monetdb.org/Documentation/ServerAdministration/Installation/Ins… <https://www.monetdb.org/Documentation/ServerAdministration/Installation/Ins…> are not working as expected. Is there any documentation on how to install the latest versions? Best, Yannis

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Bug with remote tables in transactions
by Ioannis Foufoulas 30 Mar '21

30 Mar '21

Hi, We encounter a bug with remote tables as part of transactions: sql>CREATE REMOTE TABLE rmt_tbl (id int, name varchar(20)) ON ‘mapi:monetdb://remote.host.url:50000/dbname/scm1/l_tbl <monetdb://remote.host.url:50000/dbname/scm1/l_tbl>’; operation successful sql>BEGIN TRANSACTION; auto commit mode: off sql>DROP TABLE rmt_tbl; operation successful sql>ROLLBACK; auto commit mode: on sql>DROP TABLE if exists rmt_tbl; no such table: ‘sys.rmt_tbl’ sql> It seems that after rollback the table exists in the catalogue but it does not actually exists so that drop table fails even if we have ‘if exists’ This happens only with remote tables. Best, Yannis

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RSS memory
by Roberto Cornacchia 11 Mar '21

11 Mar '21

Hi, I would appreciate some help interpreting the following memory-related issues. I've got a mserver5 instance running with cgroups v1 constraints - memory.limit_in_bytes = 17179869184 (16g) - memory.memsw.limit_in_bytes = 9223372036854771712 gdk_mem_maxsize is initialised as 0.815 * 17179869184 = 14001593384. So I get: sql>select * from env() where name in ('gdk_mem_maxsize', 'gdk_vm_maxsize'); +-----------------+---------------+ | name | value | +=================+===============+ | gdk_vm_maxsize | 4398046511104 | | gdk_mem_maxsize | 14001593384 | +-----------------+---------------+ That looks good. To my surprise, this instance gets frequently OOM-killed for reaching 16g of RSS (no swap used): memory: usage 16777216kB, limit 16777216kB, failcnt 244063804 memory+swap: usage 16777964kB, limit 9007199254740988kB, failcnt 0 kmem: usage 0kB, limit 9007199254740988kB, failcnt 0 Memory cgroup out of memory: Kill process 975803 (mserver5) score 1003 or sacrifice child Now, there are two different aspects: giving a process a memory cap and making the process respect that cap without getting killed. - if the process allocates more than defined with cgroups, then it gets killed. That is fine, it doesn't surprise me - the question is: why did monetDB surpass the 16g limit? Even more surprising, given that it "prudently" initialises itself at 80% of the available memory. Perhaps I was under the wrong assumption that MonetDB would never allocate more than gdk_mem_maxsize, but now I seem to realise that it simply uses this value to optimise its memory management (e.g. to decide how early to mmap). So, am I correct that setting gdk_mem_maxsize (indirectly via gcroups or directly via memmaxsize parameter) does not guarantee rss memory will stay underthat value? If that is true, I am back at square 1 in my quest for how to cap rss usage (without getting the process killed). Thanks for your help. Roberto

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Structure of error messages and comprehensive list of errors
by imad hajj chahine 10 Mar '21

10 Mar '21

Hi, I am trying to understand the error messages and codes reported by MonetDB, to be able to better handle error reporting, monitoring and logging. What I understand so far about the structure of an error message, it starts with error code placed between '!' and after the error message, for ex: !42000! SELECT: identifier 'xyz' unknown. and sometimes a part of the query is included. I found the list of ODBCError in "clients/odbc/driver/ODBCError.c" file, but I am not sure if this is the complete list and if it's aligned with the error codes reported by MonetDB. Is there any standard for the message error structure and where can I find the list of errors with their descriptions? Thanks.

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MonetDB development feedback and contribution
by Jamie Wang 19 Feb '21

19 Feb '21

Hi, I work for Opentext corporation and one of my dev team is heavily using MonetDB and would like to explore if there's common interest on certain functionalities that we have developed. We would be interested to exchange information, solicit feedback and the possibility to contribute to the community. Can someone please provide a few pointers as to how to proceed? Thanks in advance for your time and assistance. Jamie

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Announcement: New Oct2020-SP3 Bugfix release of MonetDB suite
by Sjoerd Mullender 19 Feb '21

19 Feb '21

The MonetDB team at MonetDB BV is pleased to announce the Oct2020-SP3 bugfix release of the MonetDB suite of programs. More information about MonetDB can be found on our website at <https://www.monetdb.org/>. For details on this release, please see the release notes at <https://www.monetdb.org/Downloads/ReleaseNotes>. As usual, the download location is <https://www.monetdb.org/downloads/>. Oct2020-SP3 Bugfix Release (11.39.13) Bug Fixes * 7049: Implement DISTINCT for GROUP_CONCAT

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MonetDB-.Net
by Mitchell Weggemans 11 Feb '21

11 Feb '21

Hey, MonetDB.Net is an entirely community driven project. Therefore, I cannot 100% guarantee it is production ready. I made some effort into testing it however, and it worked fine. If you encounter any problems, please feel free to post them here or on StackOverflow, or even to propose changes over on the GitHub repo. Regards, Mitchell.

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MonetDB-.Net
by imad hajj chahine 09 Feb '21

09 Feb '21

Hi, I am currently using Windows Monetdb ODBC driver to connect from .Net to a running monetdb server. Recently I found the github repo https://github.com/MonetDB/MonetDB-.Net and do some initial testing and it's far better in error reporting and support connection pooling. How mature is this .Net connector and is it recommended for usage in production environments and replace the ODBC driver? Is it the official connector for .Net and backed by the Monetdb team? Many thanks.

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ODBC driver Error on Windows
by imad hajj chahine 08 Feb '21

08 Feb '21

Hi, After upgrading to the Oct 2020-SP2 (11.39.11) version the ODBC driver started to throw the following exception: ERROR [IM003] Specified driver could not be loaded due to system error 126: The specified module could not be found. (MonetDB ODBC Driver, C:\Program Files\MonetDB\MonetDB ODBC Driver\lib\MonetODBC.dll) Rolling back the driver to the version june 2020-SP1(11.37.11.01) the driver is working fine. Previously some driver releases missed the 2 libraries "libeay32.dll" and "ssleay32.dll", and adding them to the ODBC driver installation folder solved the problem, but not this time. Is there any missing dlls in the installation or its a more complicated issue. Thanks. Regards

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