March 2013 - developers-list

External data atoms Issues
by Mike Gomez 11 Mar '13

11 Mar '13

Hi, i have been trying to expand data types (both core and external atoms).However, after discussions, i understood that addition of core data types will takes years( if i am not exaggerating).So, i started testing up external gdk atoms (monetdb5/modules/atoms). i am creating new atom type say mytype which is int based as below. this atom is pure int ( there are no bitfields and so on) typedef int mytype; atom mytype:int; in mal i have defined the following mal procedures( and C backends) fromstr(), tostr(), mytype(s:str):mytype, new(s:str):mytype, isnil(v:mytype):bit at this moment,it can successfully create tables and do selects. however, selects are not working as they should. these queries work. create table test(i mytype); insert into test values('453535'); select * from test these don't work. select * from test2 where i >= 5 above query gives error "types mytype(0,0) and tinyint(8,0) are not equal for column 'i'" insert into test2 values(453535); gives types int(32,0) and mytype(0,0) are not equal however, this query works !!!!!! select * from test2 where i >= '1' after testing and too many code peeping for above query, i figured out that the above query converts each element of table to string using tostr, and then compares the strings, and takes decision. so, it looks like there can be performance improvements here. However,my question is HOW do i get the queries working such as select * from test2 where i >= 5 am i missing something?? any pointers may be helpful. Thanks. -Mike

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sabdb protocol V2
by Gijs Molenaar 11 Mar '13

11 Mar '13

Hi MonetDB people, I've noticed that there has been a new version (2) of the sabdb protocol introduced. The sabdb protocol is used to send administrative command to a monetdb server. This breaks the Python API, which I just fixed, I'll commit it later. But I've noticed some strange behavior, it looks like monetdb closes the connection in some cases, not all. Specifically when I issue a status command the connection is closed, but in other cases it is not. I've fixed it now by reconnecting before every command, but I just wanted to verify if that is the right way to go. greetings, -- Gijs Molenaar http://www.astro.uva.nl/people/gijs-molenaar/

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mapi.connect() MAL Statement
by Stephen P. Morgan 08 Mar '13

08 Mar '13

I'm in the early stages of trying to write a MAL program to access a remote database using mapi.* modules, mainly to test out the function, but also for future work on distributed query processing. I find that if I issue the mapi,connect() call as follows: mal> ... mal> mid=mapi.connect("localhost",50000,"monetdb","monetdb","mal"); I get the following response: MAPI = (monetdb) /tmp/.s.monetdb.50000 QUERY = mid:=mapi.connect("localhost",50000,"monetdb","monetdb","mal"); ERROR = !IOException:mapi.connect:Could not connect: monetdbd: please specify a database The "please specify a database" part seems to be coming from tools/merovingian/daemon/client.c, i.e., the connection was attempted but was rejected by monetdbd because a database parameter was not specified. I( noticed that mapi.connect() calls SERVERconnet() which calls SERVERconnectAll() which calls mapi_connect() with NULL as the database parameter. Should SERVERconnect() (i.e., mapi.connect()) be altered to accept another parameter, database, which would be passed through SERVERconnectAll() and mapi_connect()? Or am I missing something altogether about mapi.connect()? P.S. Please excuse me if this is a foolish question. I am new to MonetDB. Thank you, Steve Morgan

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Adding data types (maybe to core), probably BUG
by Mike Gomez 08 Mar '13

08 Mar '13

Hi, i am working on monetdb so as it can be used efficiently by more users(myself included).However, the issue i seem to face ( as maybe others) is the data types. for many weeks now,I have been going through the source code, understanding and learning it.Data types in monetdb can be extended in 2 types, external and core GDK. external method problem ( maybe bug in monetdb) ======================== I have created new data type, say unsigned int 32 bit, using extensions (such as inet,color and so on).However, the bug is monetdb system doesn't use my comparison operation, instead uses the default inbuilt operators. eg. in the uint mal file( MonetDB/monetdb5/modules/atoms/uint.mal), i have declared -------------- atom uint:int; .. ..............skipped source code however, when i sort the table, the system still places negative values ahead, means instead of using my declared comparison algos, it's using internal algos. my question is how do i override that ( or is it even possible to do it). core GDK method =============== After failing that, i thought lets add the core data type uint in the gdk_atoms.c. i modified the parsor(& everything else) and the system recognizes my data type. however,when i run simple insert query such as below, i get insert into test1 values('2'); TypeException:user.s1_1[3]:'calc.uint' undefined in: _5:any := calc.uint(_4:str) however, i have got completely stuck in the MAL operators and language. so, how do i get the algebra, operations and everything right, so it works? Any pointers will help. let me know if something more is required. i am working on this out of my interest,so eventually if i get it to work somehow, the code goes back to project. Thanks for help. mike

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Announcement: New Feb2013-SP1 Bugfix release of MonetDB suite
by Sjoerd Mullender 07 Mar '13

07 Mar '13

The MonetDB team at CWI/MonetDB BV is pleased to announce the Feb2013-SP1 bugfix release of the MonetDB suite of programs. More information about MonetDB can be found on our website at <http://www.monetdb.org/>. For details on this release, please see the release notes at <http://www.monetdb.org/Downloads/ReleaseNotes>. As usual, the download location is <http://dev.monetdb.org/downloads/>. Feb 2013-SP1 bugfix release Bug Fixes * 3228: Python client - mapi.Connection.__getbyes should throw exception when 0 bytes received from socket * 3229: GRANT does not work for UPDATE * 3230: GRANT SELECT priveleges not set in SQL FUNCTIONs * 3233: getting a crash of server with segmentation fault on SLES 11 64 SP2 * 3235: MapiPP.pm unquote '0' as 'undef' * 3236: mclient \d produces no output * 3237: Assertion on BATgroup_internal * 3241: SEGFAULT on string processing when using optimizer.reduce()

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Re: MonetDB: Feb2013 - Make MALresource independent of cntxt and mb
by Fabian Groffen 04 Mar '13

04 Mar '13

Any reason for undoing 0f30e64e9bb2? On 26-02-2013 14:52:15 +0100, Martin Kersten wrote: > Changeset: 33a1b7bfcb28 for MonetDB > URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=33a1b7bfcb28 > Modified Files: > monetdb5/mal/mal_dataflow.c > monetdb5/mal/mal_interpreter.c > monetdb5/mal/mal_resource.c > monetdb5/mal/mal_resource.h > Branch: Feb2013 > Log Message: > > Make MALresource independent of cntxt and mb > > > diffs (87 lines): > > diff --git a/monetdb5/mal/mal_dataflow.c b/monetdb5/mal/mal_dataflow.c > --- a/monetdb5/mal/mal_dataflow.c > +++ b/monetdb5/mal/mal_dataflow.c > @@ -328,13 +328,13 @@ DFLOWworker(void *t) > } > MT_lock_unset(&flow->flowlock, "MALworker"); > > + q_enqueue(flow->done, fe); > if ( fnxt == 0) { > if (todo->last == 0) > profilerHeartbeatEvent("wait"); > else > - MALresourceFairness(flow->cntxt, flow->mb, usec); > + MALresourceFairness(usec); > } > - q_enqueue(flow->done, fe); > } > GDKfree(GDKerrbuf); > GDKsetbuf(0); -- Fabian Groffen fabian(a)monetdb.org column-store pioneer http://www.monetdb.org/Home

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