September 2018 - users-list

[MonetDB-users] Proofreading your professional documents
by Richard Hounslow 24 Feb '24

24 Feb '24

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GDK reported error. MT_mremap: mremap failed. !OS: Cannot allocate memory
by RanchoYuan 04 Jul '19

04 Jul '19

Hi Stefan, Thanks for your reply! We have run the query a few times with different size of data. There we used 16G RAM(actually 13.5G was used), and find the size of 10G's data is the critical point that can run the query. All of the data files' size are listed below, each file name is a table name(there are only a few tables are refered -- store_sales, date_dim, item, customer, catalog_sales, web_sales): 7.4K call_center.dat 1.6M catalog_page.dat 212M catalog_returns.dat 2.9G catalog_sales.dat 27M customer_address.dat 64M customer.dat 77M customer_demographics.dat 9.9M date_dim.dat 77B dbgen_version.dat 149K household_demographics.dat 328B income_band.dat 2.6G inventory.dat 28M item.dat 61K promotion.dat 1.7K reason.dat 1.1K ship_mode.dat 27K store.dat 323M store_returns.dat 3.8G store_sales.dat 4.9M time_dim.dat 1.2K warehouse.dat 19K web_page.dat 98M web_returns.dat 1.5G web_sales.dat 12K web_site.dat So we guess that the monetdb has no memory management? For the output of `mserver5 --version` is: MonetDB 5 server v11.27.13 "Jul2017-SP4" (64-bit, 128-bit integers) Copyright (c) 1993 - July 2008 CWI Copyright (c) August 2008 - 2018 MonetDB B.V., all rights reserved Visit https://www.monetdb.org/ for further information Found 17.0GiB available memory, 40 available cpu cores Libraries: libpcre: 8.38 2015-11-23 (compiled with 8.38) openssl: OpenSSL 1.0.2g 1 Mar 2016 (compiled with OpenSSL 1.0.2g 1 Mar 2016) libxml2: 2.9.3 (compiled with 2.9.3) Compiled by: monetdb(a)MonetDB-0.0 (x86_64-pc-linux-gnu) Compilation: gcc -g -O2 Linking : /usr/bin/ld -m elf_x86_64 And the size of processes is not limited. To let you reproduce the problem conveniently, I'll provide more details here: you can get tpc-ds from its website(we use version 2.6.0). Install the tpc-ds, access the directory v2.6.0/tools and run `./dsdgen -scale 10 -dir /home/monetdb/tpc-ds_test_data10G` to generate the data. When data has been generated, using the script /expe.sh/ to create tables and load the data. The query script is 123.tpcds.23.sql.(The syntaxs of other queries that tpc-ds generates is not suitable for monetdb all, we don't modify them all when the problem occurred). One more question, I can't get your reply email, so I don't know how to reply you, for this case, I could only send a new mail echo time. Thanks! Regards, Rancho

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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.

1 0

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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