- users-list - monetdb.org

Announcement: New Aug2018-SP1 Bugfix release of MonetDB suite
by Sjoerd Mullender 17 Oct '18

17 Oct '18

The MonetDB team at CWI/MonetDB BV is pleased to announce the Aug2018-SP1 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://dev.monetdb.org/downloads/>. Aug 2018-SP1 bugfix release (11.31.11) Build Environment * On Ubuntu 18.10 (Cosmic Cuttlefish), the libmonetdb5-server-bam package cannot be built because of an incompatibility in the libbam library (it cannot be used in a shared object. Whole System * Some subtle dependencies between RPMs have been fixed. Bug Fixes * 6640: timestamp_to_str returning incorrectly adjusted results * 6641: race condition in SQL UDF with update * 6642: Hanging query * 6648: key property potentially wrong after type conversion * 6649: Projection inside within transaction gives wrong results

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Column limit
by Oxana Dolmatova 15 Oct '18

15 Oct '18

Hello, Could you tell the limitation for number of columns in a relation and the main reason for that limitation. So far I could create relations with up to 15000 columns. When the number of columns is bigger mserver5 stops responding. Thank you and best regards, Oksana Dolmatova

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monetdb discover not finding other db's
by Frik Lubbe 24 Sep '18

24 Sep '18

Hi all, I relatively new to MonetDB, but have many year exposure to database enignes. I have 2 x vm's, almost identical with the exception of IP's and host names. both are Ubuntu Server 18.04 LTS. I have installed MonetDB on both VM's and created a db farm and a database on each. When running 'monetdb discover' on any of the VM's it finds nothing. Any help is welcome please. Regards, Frik Outputs from 'monetdbd get all /data/monetdb/dbfarm/' *VM 1:* root@ubuntu-srv-001:~# monetdbd start /data/monetdb/dbfarm/ another monetdbd is already running root@ubuntu-srv-001:~# monetdbd get all /data/monetdb/dbfarm/ property value hostname ubuntu-srv-001 dbfarm /data/monetdb/dbfarm/ status monetdbd[1941] 1.7 (Aug2018) is serving this dbfarm mserver /usr/bin/mserver5 logfile /data/monetdb/dbfarm//merovingian.log pidfile /data/monetdb/dbfarm//merovingian.pid sockdir /tmp listenaddr 0.0.0.0 port 50000 exittimeout 60 forward proxy discovery yes discoveryttl 600 control yes passphrase {SHA512}a73f1d86383446438ac64f56e15ada38b41fbb18f029d2181723aeb2acac6a831f60e5fdbd64ac2c8c70e035dd44cbbe3b45565ef2d58feb2821a2078c7fad35 mapisock /tmp/.s.monetdb.50000 controlsock /tmp/.s.merovingian.50000 root@ubuntu-srv-001:~# monetdb discover root@ubuntu-srv-001:~# *VM 2:* root@ubuntu-srv-002:~# monetdbd get all /data/monetdb/dbfarm/ property value hostname ubuntu-srv-002 dbfarm /data/monetdb/dbfarm/ status monetdbd[2373] 1.7 (Aug2018) is serving this dbfarm mserver /usr/bin/mserver5 logfile /data/monetdb/dbfarm//merovingian.log pidfile /data/monetdb/dbfarm//merovingian.pid sockdir /tmp listenaddr 0.0.0.0 port 60001 exittimeout 60 forward proxy discovery yes discoveryttl 600 control yes passphrase {SHA512}a73f1d86383446438ac64f56e15ada38b41fbb18f029d2181723aeb2acac6a831f60e5fdbd64ac2c8c70e035dd44cbbe3b45565ef2d58feb2821a2078c7fad35 mapisock /tmp/.s.monetdb.60001 controlsock /tmp/.s.merovingian.60001 root@ubuntu-srv-002:~#

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SQLcopyinto.java
by Roberto Cornacchia 20 Sep '18

20 Sep '18

I'm trying to debug n issue I have with data disappearing after a database restart. Because part of the process for creating the table involves a mixed Mapi / JDBC approach as described in monetdb-java/example/SQLcopyinto.java, I started from this example. When I run it though, I get a final count of 0 (should be 100). Can anyone confirm? Mar2018, JDBC 2.28 Roberto

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Join Order Benchmark on MonetDB
by Junxiong Wang 19 Sep '18

19 Sep '18

Hello, I am currently evaluating the performance of MonetDB on the Join Order Benchmark, proposed by Leis et al.(http://www.vldb.org/pvldb/vol9/p204-leis.pdf <http://www.vldb.org/pvldb/vol9/p204-leis.pdf>). There are a few queries where performance seems suboptmal, e.g., query 16b and 17e (https://github.com/gregrahn/join-order-benchmark <https://github.com/gregrahn/join-order-benchmark>): MonetDB takes around 400 seconds to evaluate query 17e with a single thread, more than 20 seconds with 48 threads, Postgres takes only around 9 seconds. I suspect that the query optimizer selects the wrong plan, this is the output of the plan command. | project ( | | | group by ( | | | | join ( | | | | | join ( | | | | | | join ( | | | | | | | join ( | | | | | | | | join ( | | | | | | | | | join ( | | | | | | | | | | table(sys.movie_companies) [ "movie_companies"."movie_id" NOT NULL as "mc"."movie_id", "movie_companies"."company_id" NOT NULL as "mc"."company_id" ] COUNT , | | | | | | | | | | select ( | | | | | | | | | | | table(sys.company_name) [ "company_name"."id" NOT NULL HASHCOL as "cn"."id", "company_name"."country_code" as "cn"."country_code" ] COUNT | | | | | | | | | | ) [ "cn"."country_code" = varchar(255) "[us]" ] | | | | | | | | | ) [ "mc"."company_id" NOT NULL = "cn"."id" NOT NULL HASHCOL ], | | | | | | | | | table(sys.title) [ "title"."id" NOT NULL HASHCOL as "t"."id" ] COUNT | | | | | | | | ) [ "t"."id" NOT NULL HASHCOL = "mc"."movie_id" NOT NULL ], | | | | | | | | table(sys.cast_info) [ "cast_info"."person_id" NOT NULL as "ci"."person_id", "cast_info"."movie_id" NOT NULL as "ci"."movie_id" ] COUNT | | | | | | | ) [ "ci"."movie_id" NOT NULL = "t"."id" NOT NULL HASHCOL , "ci"."movie_id" NOT NULL = "mc"."movie_id" NOT NULL ], | | | | | | | table(sys.name) [ "name"."id" NOT NULL HASHCOL as "n"."id", "name"."name" NOT NULL as "n"."name" ] COUNT | | | | | | ) [ "n"."id" NOT NULL HASHCOL = "ci"."person_id" NOT NULL ], | | | | | | table(sys.movie_keyword) [ "movie_keyword"."movie_id" NOT NULL as "mk"."movie_id", "movie_keyword"."keyword_id" NOT NULL as "mk"."keyword_id" ] COUNT | | | | | ) [ "t"."id" NOT NULL HASHCOL = "mk"."movie_id" NOT NULL, "ci"."movie_id" NOT NULL = "mk"."movie_id" NOT NULL, "mc"."movie_id" NOT NULL = "mk"."movie_id" NOT NULL ], | | | | | select ( | | | | | | table(sys.keyword) [ "keyword"."id" NOT NULL HASHCOL as "k"."id", "keyword"."keyword" NOT NULL as "k"."keyword" ] COUNT | | | | | ) [ "k"."keyword" NOT NULL = clob "character-name-in-title" ] | | | | ) [ "mk"."keyword_id" NOT NULL = "k"."id" NOT NULL HASHCOL ] | | | ) [ ] [ sys.min no nil ("n"."name" NOT NULL) NOT NULL as "L3"."L3" ] | | ) [ "L3"."L3" NOT NULL as "L4"."member_in_charnamed_movie" ] | +-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ I was wondering whether anyone might have a hint about what the problem could be and how one could improve performance for those specific queries? Thanks a lot!

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Measure the memory footprint of Monetdb from an SQL client
by Mahmoud Mohsen 12 Sep '18

12 Sep '18

Hello, Is there away to measure the physical or virtual memory consumption of Monetdb using an SQL query. Something similar to select * from storage() where table_name = name; I believe storage() helps with the disk consumption not main memory consumption, am I right? Thank you a lot in advance, Mahmoud Mohsen

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COPY INTO FILE - Folder permission
by Ariel Abadi 10 Sep '18

10 Sep '18

Hi! We are running some "exports" using the COPY INTO FILE, the problem we are facing is that the file created by monetdb is Read Write ONLY by the user running the database. -rw------- 1 root monet 9477 Sep 7 15:08 exp.csv Is there any way so the created file has also RW permission to the group and NOT only the user. In this case, we are using an NFS share so we are not able to use setfacl. Does anybody has an idea how to solve this ? Thanks a lot in advance! Rgds Ariel

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About Monetdb Query Plan
by Junxiong Wang 07 Sep '18

07 Sep '18

Hello, I am currently working on a project related to query optimization I have several questions, 1) Is it possible to force the query engine to use the specified join order? 2) When I change the table order in the “FROM” clause, the query time varies a lot (many orders of magnitude)? Does the table order in the “FROM” clause affect the query plan? 3) I want to know the details of MonetDB query plan. When I use “explain” command, I just get the MAL code. Are there any tools to visualize it, just like PostgreSQL “analyze" command? Thanks a lot.

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About Monetdb Query Plan
by Junxiong Wang 06 Sep '18

06 Sep '18

Hello, I am currently working on a project related to query optimization I have several questions, 1) Is it possible to force the query engine to use the specified join order? 2) When I change the table order in the “FROM” clause, the query time varies a lot (many orders of magnitude)? Does the table order in the “FROM” clause affect the query plan? 3) I want to know the details of MonetDB query plan? But when I use “explain” command, I just get the MAL code. Are there any tools to visualize it, just like PostgreSQL “analyze" command? Thanks a lot.

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How to enable SQLSTATE error code in mclient
by Murthy, Gautham 06 Sep '18

06 Sep '18

Hello, How do we enable SQLSTATE error code on mclient ? Thank You, Gautham

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