September 2020 - users-list

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

24 Feb '24

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SELinux problems
by Arjen P. de Vries 29 Dec '21

29 Dec '21

Hi all, Not really a bug report because I did not manage to figure out the cause. However, after upgrading from FC31 to FC32 I could not login any more, due to SELinux problems. Auto-relabeling did not work, nothing really... ... until I did dnf uninstall MonetDB-selinux. I came to this point because trying to give systemd services the correct labels with restorecon failed with an error referencing a monetdb specific file. I do not have the details unfortunately, but if you get problems, beware that MonetDB SELinux package and systemd may interfere in some way beyond my knowledge of these services. Best regards, Arjen PS: Some output from logs: sudo ausearch -c monetdb -m AVC,SELINUX_ERR [..] ---- time->Sat May 2 20:57:01 2020 type=AVC msg=audit(1588445821.693:203): avc: denied { open } for pid=1232 comm="monetdbd" path="/etc/resolv.conf" dev="dm-0" ino=3409775 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:default_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.043:1194): avc: denied { execute } for pid=2861 comm="(monetdbd)" name="monetdbd" dev="dm-0" ino=2147256 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 trawcon="unconfined_u:object_r:monetdbd_exec_t:s0" ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.043:1195): avc: denied { execute_no_trans } for pid=2861 comm="(monetdbd)" path="/usr/bin/monetdbd" dev="dm-0" ino=2147256 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 trawcon="unconfined_u:object_r:monetdbd_exec_t:s0" ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.044:1196): avc: denied { map } for pid=2861 comm="monetdbd" path="/usr/bin/monetdbd" dev="dm-0" ino=2147256 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 trawcon="unconfined_u:object_r:monetdbd_exec_t:s0" ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.714:1197): avc: denied { remove_name } for pid=1232 comm="monetdbd" name="merovingian.pid" dev="tmpfs" ino=34369 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 trawcon="system_u:object_r:monetdbd_var_run_t:s0" ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.714:1198): avc: denied { unlink } for pid=1232 comm="monetdbd" name="merovingian.pid" dev="tmpfs" ino=34369 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:12:56 2020 type=AVC msg=audit(1588446776.714:1199): avc: denied { write } for pid=1232 comm="monetdbd" name=".merovingian_lock" dev="dm-0" ino=5899443 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 trawcon="system_u:object_r:monetdbd_lock_t:s0" ---- time->Sat May 2 21:13:15 2020 type=AVC msg=audit(1588446795.214:1209): avc: denied { read } for pid=2925 comm="(monetdbd)" name="passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:13:15 2020 type=AVC msg=audit(1588446795.214:1210): avc: denied { open } for pid=2925 comm="(monetdbd)" path="/var/lib/sss/mc/passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:13:15 2020 type=AVC msg=audit(1588446795.214:1211): avc: denied { map } for pid=2925 comm="(monetdbd)" path="/var/lib/sss/mc/passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:14:24 2020 type=AVC msg=audit(1588446864.487:1281): avc: denied { read } for pid=3072 comm="(monetdbd)" name="passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:14:24 2020 type=AVC msg=audit(1588446864.487:1282): avc: denied { open } for pid=3072 comm="(monetdbd)" path="/var/lib/sss/mc/passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 ---- time->Sat May 2 21:14:24 2020 type=AVC msg=audit(1588446864.487:1283): avc: denied { map } for pid=3072 comm="(monetdbd)" path="/var/lib/sss/mc/passwd" dev="dm-0" ino=524514 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=file permissive=1 -- ==================================================================== ICIS, office M1.00.05 Radboud University Mercator 1 Faculty of Science Toernooiveld 212 arjen(a)cs.ru.nl NL-6525 EC Nijmegen, The Netherlands +31-(0)24-365 2354 ===================== http://www.informagus.nl/ ==================== -- ==================================================================== ICIS, office M1.00.05 Radboud University Mercator 1 Faculty of Science Toernooiveld 212 arjen(a)cs.ru.nl NL-6525 EC Nijmegen, The Netherlands +31-(0)24-365 2354 ===================== http://www.informagus.nl/ ====================

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Thread safety in python UDFs
by Ioannis Foufoulas 01 Oct '20

01 Oct '20

Hi, One question on python udfs. What about thread safety? In case of concurrent execution of numpy UDFs should the UDF developer use thread-safe structures or Monetdb handles this in some way? For example, pandas is not thread safe. This means that it should not be used in a UDF? Best, Yannis

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Building MonetDBe from source
by Avik Sengupta 24 Sep '20

24 Sep '20

Hi, I've been trying to build MoneDBe from source, using Github master. I do not want to build the full executables, so I have used cmake --build . --target monetdbe With this, I am able to successfully build libmonetdbe.so. So that is great. However there does not seem to be an install-monetdbe or similar target. Running the `install` target tries to compile the whole application, which is not what I want. How do I copy the compiled artifacts (libmonetdbe.so and dependencies) to my install prefix? I'm trying not to have to manually copy the libraries. Regards - Avik

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.mal and .sql files in Oct2020 lib folder
by Roberto Cornacchia 24 Sep '20

24 Sep '20

Hi there, I'm trying to compile from the Oct2020 branch and I have a question about the /lib64/monetdb5 folder. This folder used to contain .mal files. It also contained an autoload/ subfolder and a createdb/ subfolder (with .sql files). I don't see the same in the Oct2020 installation. I see that the content of /sql/scripts/CMakeLists.txt is entirely commented out. Is the installation of all these files temporarily disabled during development, or is this handled differently now? Roberto

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Re: Internals of intermediate results in MonetDB
by Guodong Jin 24 Sep '20

24 Sep '20

Thanks! The point to MAL plan really helps me out! Best, Guodong On Sep 21, 2020, 06:00 -0400, users-list-request(a)monetdb.org, wrote: > Send users-list mailing list submissions to > users-list(a)monetdb.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.monetdb.org/mailman/listinfo/users-list > or, via email, send a message with subject or body 'help' to > users-list-request(a)monetdb.org > > You can reach the person managing the list at > users-list-owner(a)monetdb.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of users-list digest..." > > > Today's Topics: > > 1. Internals of intermediate results in MonetDB (Guodong Jin) > 2. Re: Internals of intermediate results in MonetDB (Martin Kersten) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 20 Sep 2020 23:31:50 -0400 > From: Guodong Jin <guod.jin(a)gmail.com> > To: users-list(a)monetdb.org > Subject: Internals of intermediate results in MonetDB > Message-ID: <932d01d5-a742-4f57-8e19-ba7599667e42@Spark> > Content-Type: text/plain; charset="utf-8" > > Hi all, > > Thanks for your hard works on this great open source project. > I?m a student newly working on MonetDB to implement some research ideas, and I want to understand internals of how MonetDB chooses to materialize and how it represents intermediate results. > As I understand, table data and intermediate results in MonetDB are all stored as BATs, but I?m not sure if there are some special optimizations on BATs, rather than just array(s) of atoms. Here are two simple examples to elaborate my questions a little bit: > > ?? ?1.Given two tables,?Items(id, order, price, tax), and?Orders(id, discount). > ?? ? ? ? ?Items > ?? ? ? ? ? ? ? ? ?[I1, I2, I3, I4, I5, I6, I7, I8, I9, I10, I11...] > ?? ? ? ? ? ? ? ? ?[O3, O3, O3, O3, O3, O3, O3, O3, O3, O3, O4...] > ?? ? ? ? ? ? ? ? ?[10, 11, 20, 15, 110, 80, 90, 12, 13, 88, 30...] > ?? ? ? ? ? ? ? ? ?[0.1, 0.15, 0, 0.1, 0.1, 0.15, 0.11, 0.18, 0.10, 0.15, 0.20, ...] > ?? ? ? ? ?Orders > ?? ? ? ? ? ? ? ? ?[O1, O2, O3] > ?? ? ? ? ? ? ? ? ?[0.8, 0.9, 0.95] > > ?? ? ? ? ?When we perform a join between these two tables on the field `order` (one-to-many relationship represented by the primary-foreign key, O3 matches with [I1, I2, ?, I10]),?in the output intermediate BATs of the join, will MonetDB duplicate `O3` 10 times? Are there any optimizations currently in MonetDB to remove/reduce the duplication? > > ?? ?2. Given a table?item(id, price, tax), when MonetDB performs the filter `price<10` on the table,?will MonetDB actually copy all matched tuples into intermediate BATs? Or just keep a list of OIDs of matched tuples as references? > > Thanks! > > Best, > Guodong >

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Internals of intermediate results in MonetDB
by Guodong Jin 21 Sep '20

21 Sep '20

Hi all, Thanks for your hard works on this great open source project. I’m a student newly working on MonetDB to implement some research ideas, and I want to understand internals of how MonetDB chooses to materialize and how it represents intermediate results. As I understand, table data and intermediate results in MonetDB are all stored as BATs, but I’m not sure if there are some special optimizations on BATs, rather than just array(s) of atoms. Here are two simple examples to elaborate my questions a little bit: 1.Given two tables, Items(id, order, price, tax), and Orders(id, discount). Items [I1, I2, I3, I4, I5, I6, I7, I8, I9, I10, I11...] [O3, O3, O3, O3, O3, O3, O3, O3, O3, O3, O4...] [10, 11, 20, 15, 110, 80, 90, 12, 13, 88, 30...] [0.1, 0.15, 0, 0.1, 0.1, 0.15, 0.11, 0.18, 0.10, 0.15, 0.20, ...] Orders [O1, O2, O3] [0.8, 0.9, 0.95] When we perform a join between these two tables on the field `order` (one-to-many relationship represented by the primary-foreign key, O3 matches with [I1, I2, …, I10]), in the output intermediate BATs of the join, will MonetDB duplicate `O3` 10 times? Are there any optimizations currently in MonetDB to remove/reduce the duplication? 2. Given a table item(id, price, tax), when MonetDB performs the filter `price<10` on the table, will MonetDB actually copy all matched tuples into intermediate BATs? Or just keep a list of OIDs of matched tuples as references? Thanks! Best, Guodong

2 1

Merge table error with one table
by Ioannis Foufoulas 17 Sep '20

17 Sep '20

Hi, we encounter an error when only one table is added to a merge table definition During a query like "select * from merge table” we get: “Table: missing ')'" Probably merge tables cannot contain just one table but the returned error looks like a syntax error. Some more info to reproduce: the table that has been added to the merge table is a remote table. Best, Yannis

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Recommended compiler version and flags for Linux x86_64
by Daniel Glöckner 15 Sep '20

15 Sep '20

Hi, I'm currently building and testing MonetDB on CentOS7, x86_64. I was wondering about the recommended compiler version and compiler flags. So far I'm using gcc 9 and specifically enabled SSE3 extensions (though I did not notice any performance gain). Here's my cmake command cmake3 -DCMAKE_C_FLAGS="pthread -msse3 -O -Wall" -DCMAKE_INSTALL_PREFIX=../install ../MonetDB Is there a list of recommended compiler flags? Kind regards, Daniel

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Nested tables?
by louie＠gmx.cn 14 Sep '20

14 Sep '20

Hi, Does MonetDB support nested tables? Oracle diagram for reference: https://docs.oracle.com/cd/B10501_01/appdev.920/a96594/adobjdes.htm#441615 Thanks, Louie

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