Hello,
I am interested in evaluating MonetDB/XQuery. I have some XML collections
for a project I work on that are of 1-2 million individual XML documents
for which I use XQuery to access for OLAP style reporting operations. This
is a Java-based project, and while working on this project I developed a
thin XQuery-centric API so that I could evaluate/use many different XQuery
implementations, which my company released as an open source project
called Xaj (http://sourceforge.net/projects/xaj). Currently I am using a
Berkeley DB XML implementation, but am interested in exploring other
options.
I'd like to implement a MonetDB version of this API now, but I am having
some difficulty finding out how to effectively access MonetDB through
Java. So far I was able to use the MonetDB JDBC driver to construct XQuery
statements and get XML results, and also I was able to construct MonetDB
pf:add-doc() statements to add documents, but I am wondering if this is
the best approach (and if so, how to add documents to a remote MonetDB
server using the pf:add-doc() mechanism).
The API I am trying to implement you can view here, to give you an idea
what I'm trying to do:
http://xaj.svn.sourceforge.net/viewvc/xaj/xaj/src/net/sf/xaj/XmlDb.java?rev…
It was somewhat modeled after the defunct XML:DB API, but focused just on
add/store/XQuery operations. Any help/advise would be greatly appreciated!
-- m@
Dear MonetDB users and developers,
The MonetDB team at CWI is pleased to announce the new "Jun2008" release of
the MonetDB suite of programs.
For MonetDB/XQuery, this release marks the roll forward from the old
"milprint_summer"-based Pathfinder compiler to the new "Algebra"-based
Pathfinder compiler.
MonetDB/SQL has been extended with initial support for OpenGIS via the
"Geom[etry]" extension module, aka. MonetDB/SQL/GIS.
Additionally, the configure defaults for compilation from sources on
Unix(-like) systems as well as the Windows installers have been cleaned-up.
For more information, please see the detailed release notes at
http://monetdb.cwi.nl/Development/Releases/Version4.24/
IMPORTANT NOTE:
Before upgrading to the latest "Jun2008" release from any previous release
of MonetDB, please make a dump of your database, and rename/move/backup the
database directories (dbfarm, sql_logs, xquery_logs). After the upgrade,
restore your database, again. Once you have checked and confirmed the
correctness of the restore, you can delete the above renamed/moved/backed-up
old database directories.
For more information, please see the detailed release notes at
http://monetdb.cwi.nl/Development/Releases/Version4.24/
The new release consists of the following packages:
MonetDB Common 1.24.0
MonetDB Clients 1.24.0
MonetDB4 Server 4.24.0
MonetDB4 XQuery 0.24.0
MonetDB5 Server 5.6.0
MonetDB5 SQL 2.24.0
MonetDB5 Geom 0.4.0
monetdb-1.8-jdbc.jar
There is of course also a new "Super Source Ball", a tarball containing the
combined sources.
All this is available on our SourceForge project page. See
https://sourceforge.net/project/showfiles.php?group_id=56967 for the
downloadable files.
Enjoy!
The MonetDB development team.
--
| Dr. Stefan Manegold | mailto:Stefan.Manegold@cwi.nl |
| CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ |
| 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 |
| The Netherlands | Fax : +31 (20) 592-4312 |
Does anyone know how to get the Python libs running on Win XP?
Tried it with latest trunk and release versions of Monet, and with Python
2.4 and 2.5
File "C:\Python25\lib\MonetDB\MapiLib.py", line 7, in <module>
import _MapiLib
ImportError: DLL load failed: The specified module could not be found.
_MapiLib.pyd is there alright. Is this a version problem?
Thanks,
Kees
Hi,
I hope you don't get asked this question too often, I've had a look for
FAQs but couldn't find anything obvious.
I'm trying to load some data into MonetDB (built on a i386 Debian "etch"
box from MonetDB-Feb2008-SuperBall.tar.bz2) and I'm getting strange
problems. I've got a table with 11 columns (2 int, 5 varchar, 4 date)
and about 38 million rows (the text file I want to pull in is 3.3GB).
If I try COPYing the data in, Monet alternately stops making progress
(the computer is reading from the disk slowly, so maybe it's just going
to take a *long* time to finish) or crashes with the following message:
!SQLException:importTable:failed to import table
!ERROR: GDKload: cannot mmap(): name=24/2470, ext=tail.priv
!OS: Cannot allocate memory
!ERROR: GDKload failed: name=24/2470, ext=tail.priv
If I try splitting the file into smaller pieces (about a gig each),
things work and I end up with the data in the database. It would be
nice to know why I needed to split the file up first.
Now I've got the data in I tried running a few queries to make sure
everything went OK. I'm getting some very strange results when doing
aggregations. The following work:
SELECT count(*) FROM source_livestock;
+----------+
| count_ |
+==========+
| 37898310 |
+----------+
SELECT sex_code, count(*) FROM source_livestock GROUP BY sex_code;
+----------+---------------+
| sex_code |count_sex_code |
+==========+===============+
| M | 17505304 |
| F | 20392997 |
| null | 9 |
+----------+---------------+
This last query came back amazingly quickly, about ten times faster than
Postgres. Monet looks like a fairly amazing database if I can routinely
expect queries to be this much faster.
SELECT count(*);
+--------------+
| single_value |
+==============+
| 1 |
+--------------+
but the following don't do what I'd expect:
SELECT count(1);
MAPI = monetdb@endemic:50001
ACTION= read_line
QUERY = select count(1);
ERROR = Connection terminated
I'd expect to get a single row with a single value containing the
number 1 from this query. And for the following query I'd expect to get the same, just with the result being zero.
SELECT count(null);
!syntax error, unexpected sqlNULL in: "select count(null"
This is how I found the bug:
SELECT sex_code, count(1) FROM source_livestock GROUP BY sex_code;
!TypeException:user.s3_1[26]:'aggr.count_no_nil' undefined in: _36:bat[:any,:int] := aggr.count_no_nil(_35:bte, _31:bat[:oid,:oid], _32:bat[:oid,:oid])
!SQLException:sql.rsColumn:Cannot access descriptor
!WARNING: BATdescriptor: range error 1
I've come to expect COUNT(*) and COUNT(1) as having the same semantics.
But I may be missing something.
SELECT sex_code, count(1+1) FROM source_livestock GROUP BY sex_code;
!TypeException:user.s4_1[28]:'aggr.count_no_nil' undefined in: _39:bat[:any,:int] := aggr.count_no_nil(_38:bte, _32:bat[:oid,:oid], _33:bat[:oid,:oid])
+----------+---------------------+
| sex_code |sql_add_single_value |
+==========+=====================+
| M | monetdb |
+----------+---------------------+
This second one is particularly bad because I get an incorrect answer
back. Any idea what I'm doing wrong?
Thanks,
Sam
Hello,
i was evaluating MonetDB. Got the Server running finr on Windows XP x64. I created about 12 Tabled by using a JDBC Client, then the Server died instantly. Since then when I start the Server it dies asap when I either start the Windows Client or perform a JDBC connection. I get no error log, no message, nothing. Has anybody an idea how to get MonetDB to stop crashing on connect?
Thanks,
Robert
Robert Schumacher, Senior Software Developer
prevero Systems GmbH
Landsberger Straße 154
80339 München
Tel +49 89 455 77 - 0
Fax +49 89 455 77 - 200
Registergericht: Amtsgericht München, HRB 143809 -- Geschäftsführer: Matthias Thurner
Bitte beachten Sie unsere Veranstaltungshinweise unter www.prevero.de
Rt Ibmer wrote:
> Hi - I use a SSH client to access my Fedora 8 core box. When I was using the RELEASE built I was able to use left/right/up/down/home/end keys within mclient to edit the line. For instance I could push up arrow to have it automatically cycle through the previous lines, and then use left arrow to move over to a part of the line and process to change it.
>
There have not been changes in that area. Running against the current
also does not show the problem
> That all worked fine under the RELEASE build.
>
> However now that I have built from source the nightly stable (as of a couple nights ago) I can no longer use these keys. For instance when I press UP arrow it simply adds "^[[A" to the line. Other arrow keys / home /end do something similar.
>
Nothing has changed in this area. I mostly use a Putty ssh client to
access my machine and work with mclient. It works as expected. You may
want to check the preference setting of the ssh client.
> Not sure but I think something broke regarding this at some point between the released build and the stable nightly. Thanks.
>
>
>
>
>
> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
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> _______________________________________________
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>
Alexandru Toth wrote:
> Hello,
>
> I'm the developer of Cubulus OLAP
> (http://sourceforge.net/projects/cubulus/ ) .
Hello Alexandru
Welcome to the MonetDB user community.
>
> On the roadmap there is a hint about replication, coming in SQL 2.2
> (February 2008) release. Is it implemented ? If not, is it possible to use
We have been experimenting with replication techniques. Some of the
hooks have been included in the distribution.
However, we are not yet satisfied and with the result. It remains on our
R&D list to come up with a novel
and efficient solution.
> some existing software ex: http://dbreplicator.org/
Middleware solutions could potentially provide a short term solution.
However, we don't know if they are powerful enough or require
functionality currently not available in our JDBC driver.
>
> Or, is it possible to load data into "master", stop it, sync the
> dbfarm to several slaves (into new directories), and re-start the
> slaves with the new dbfarm path ? Of course, slaves are used as
> read-only copies.
ofcourse, provided you don't forget to copy the sql_logs as well.
You can even instruct the server that the database is readonly.
See the documentation :
http://monetdb.cwi.nl/projects/monetdb/SQL/Documentation/Storage-Modes.html
regards, Martin
>
> -Alex
>
>
Sjoerd Mullender wrote:
> Martin Kersten wrote:
>
>> Sjoerd,
>>
>> I was planning to try out the installers on my Vista machine.
>> The previous version is v5.4.0 installed
>>
>> Uninstalling it gives the following error:
>> There is a problem with this Windows Installer
>> package. A program required for this install
>> to complete could not be run. Contact your
>> support personnel or package vendor.
>>
>> You want specific information, or should i manually
>> remove the C:\Program Files\CWI/MonetDB5
>>
>
> Manually removing won't help unless you also edit the registry.
>
> My guess is that it complains about the uninstall of the ODBC driver.
> Can you run
> "C:\Program Files\CWI\MonetDB5\odbcinstall" /Uninstall
> (I think that is the exact name) manually from a cmd window?
>
ran this program , which worked.
However, uninstalling MonetDB still gives the same error.
Dear MonetDB developer and users,
For convenience of both developers and users as well as to comply even more
with open source standards, we now set/use the following defaults for the
configure options
--enable-strict, --enable-assert, --enable-debug, --enable-optimize
(Unless specified differently, the same defaults are used for both the
"Stable" release branches and the "Current" development trunk.)
When compiling from CVS sources
(as mainly done by developers):
strict=yes assert=yes debug=yes optimize=no (*)
When compiling from packaged/distributed sources (i.e., tarballs)
(as mainly done by users):
strict=no assert=no debug=no optimize=no (*)
For building binary distributions (RPMs, MSIs):
strict=no assert=no debug=no optimize=yes
With nightly testing for the "Stable" release branches:
strict=yes assert=no debug=no optimize=yes
With nightly testing for the "Current" development trunk:
strict=yes assert=yes debug=no optimize=yes
(*)
IMPORTANT NOTE:
Since "--enable-optimize=yes" is no longer the default for any case except
binary packages, it is *strongly recommended* to (re)compile everything from
scratch, *explicitly configured* with
"--enable-debug=no --enable-optimize=yes",
in case you want/need to run any performance experiments with MonetDB!
(Please note:
"--enable-X=yes" is equivalent to "--enable-X", and
"--enable-X=no" is equivalent to "--disable-X".)
Don't hesitate to ask in case you have any questions!
Enjoy!
Stefan
--
| Dr. Stefan Manegold | mailto:Stefan.Manegold@cwi.nl |
| CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ |
| 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 |
| The Netherlands | Fax : +31 (20) 592-4312 |
Rt Ibmer wrote:
> Hi - I have an int column with several million rows of data. What is the fastest way to write a query to get the median value of the column? Apparently there is no median() function in SQL. A web search revealed lots of various talk about using stored procedures and fancy functions. None of this looked like it would be very efficient. I searched these archives but didn't see a single mention of median. Thank you!
>
True, the complexity of the median() in essence requires a partial sort
of the complete list.
It is a member of a group of statistical functions. A feature request
has been added to the list.
>
>
>
>
>
> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
> just about anything Open Source.
> http://sourceforge.net/services/buy/index.php
> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/monetdb-developers
>