August 2016 - users-list

How could I obtain the running time information in the MAL interface of mclient?
by Xu,Wenjian 07 Aug '16

07 Aug '16

Hi all, MonetDB version: 11.23.7 Ubuntu version: 14.04 How could I obtain the running time information in the MAL interface of mclient? I tried to use the *--interactive* option but it did not work. Specifically, I do the following: =============================================== $ *mclient -dnba2009 -lmsql --interactive=ms* Welcome to mclient, the MonetDB interactive terminal (Jun2016-SP1) Type \q to quit, \? for a list of available commands msql>\<query.txt // I save the MAL instructions of a query (obtained from EXPLAIN statement) in this file msql>user.s1_3("1998"); // call the function of that query % sys.player, sys.player, sys.player # table_name % p_lastname, p_lastseason, p_weight # name % char, int, int # type % 100, 4, 3 # length [ "Wheeler", 1998, 165 ] [ "Baker", 1998, 175 ] [ "Garnett", 1998, 186 ] ...... ======================================================== I would like to obtain the running time information after getting the result of that query. How can I do it? Any help would be appreciated. Best, Wenjian

4 6

Strange behaviour with optimizer.pushselect and batalgebra.like
by Moritz Bruder 05 Aug '16

05 Aug '16

Hi, I get a really strange behaviour with the *pushselect* optimizer for this piece of MAL code: http://codepad.org/bqulPEtV . The problem I'm having is, that depending on whether the *pushselect* optimizer is used or not, the query will yield different results. Context info: 1. MonetDB version number: 11.23.3 2. Operating system platform: Linux 4.6.4-1-ARCH #1 SMP PREEMPT Mon Jul 11 19:12:32 CEST 2016 x86_64 GNU/Linux 3. Compiled from source tarball 4. http://codepad.org/bqulPEtV Regards, Moritz

1 0

Using MonetDB with Scala/Slick
by Pablo S 05 Aug '16

05 Aug '16

I develop in Scala, and need to access a MonetDB database. I use the Scala standard, Slick, however Slick doesn't have a driver to access MonetDB. I'm interested in developing a Slick/MonetDB driver (it's a JDBC wrapper) but I'd like to know first if someone already started the process (we could join forces). Please let me know. Thanks.

1 0

When would the function group.multicolumn() used?
by Xu,Wenjian 03 Aug '16

03 Aug '16

Hi all, I found the following new MAL function in the new release of version 11.23.3: ============================================================ pattern group.multicolumn(b:bat[:any]...) (ref:bat[:oid],grp:bat[:oid],hist:bat[:any]) address GROUPmulticolumngroup; comment Derivation of a group index over multiple columns. ============================================================ I thought I may be used by queries with multiple attributes in the GROUP BY clause. So I tried to EXPLAIN such a query (e.g., SELECT ... FROM... GROUP BY ColA, ColB), but it is still compiled with multiple group.subgroup() followed by a group.subgroupdone(). So, when would this function group.multicolumn() used? Thanks, Wenjian

1 0