July 2005 - users-list

[MonetDB-users] RHEL 3 RPMs
by Henk van Lingen 28 Apr '06

28 Apr '06

Hi, Is there a special reason there are no i686 RPM's anymore like there were until 4.6.0_rc2? I think it's a bit weird there are RPM's for the hobby OS 'FedoraCore' but not for the much used server OS 'RedHat Enterprise 3 (and 4)'? The FedoraCore (which Core?) needs libstdc++.so.6 whereas RHEL 3 only has libstdc++.so.5 ... There also seems to be no SRPM's. Cheers, -- Henk van Lingen, Systems & Network Administrator (o- -+ Dept. of Computer Science, Utrecht University. /\ | phone: +31-30-2535278 v_/_ http://henk.vanlingen.net/ http://www.tuxtown.net/netiquette/

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[MonetDB-users] New
by rita kelly 08 Aug '05

08 Aug '05

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[MonetDB-users] Using MonetDB for financial time series analysis
by Joel Reymont 28 Jul '05

28 Jul '05

Howdy! I'm looking to use the framework for high-performance storing and querying of financial time series, i.e. ticks arriving from the exchange. I need to be able to store 500-1000 (or more) ticks per second and would like to be able to quickly find similar time series given a date range. I'm looking to create a cheaper alternative to www.kx.com with their KDB and K language. For each tick I need to store the datetime, symbol, trade type (bid/ask/trade), price and volume. How would I do a similarity search? I would like to select a portion of my stock chart (for example) and find subsequences in other stocks that match the pattern. What is the best way to take differences in scale be taken into account? Would I need to calculate the Euclidian distance myself? If I am to write wavelet or Fast Fourier Transform code, should I write it in MIL or use the Python/Perl/etc interface? Thanks for your help and please use the link in my signature to read up on my project. Thanks, Joel -- http://wagerlabs.com/uptick

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[MonetDB-users] Triggers in MonetDB
by Arthur van Bunningen 17 Jul '05

17 Jul '05

Dear all, First my compliments with this piece of useful and implemented research. Second I was wondering if there is a possibility to have so-called "triggers" in MonetDB such as in for example PostgreSQL [1] or if there are other ways to use MonetDB as an "active database". If anyone has experiences in this field or can point me to the right place to look for this experience I would be very thankful. Kind regards, Arthur van Bunningen [1] http://www.postgresql.org/docs/8.0/static/triggers.html -- Ir. A.H. van Bunningen - PhD Student, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: bunninge(a)cs.utwente.nl, Phone: +31 53 489 4290, Room: ZI3061 WWW: http://www.cs.utwente.nl/~bunninge

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[MonetDB-users] jdbc related tests fail with a : connection refused
by Arnold Reuser 16 Jul '05

16 Jul '05

Hi all, Currently I've installed MonetDB & SQL on SUSE9.2 Pro from source as it was in CVS on 15 July. The problem I have is that all my jdbc related tests fail with a : Database connect failed: Unable to connect (localhost:48016): Connection refused , MServer with sql option and MapiClient runs just fine. Another example : % java -jar share/MonetDB/lib/MonetDB_JDBC.jar -umonetdb password: <monetdb> Currenlty also fails with the given username, password. Is the documentation or are the tests outdated? Or is there something I should be aware of before I can run the java part correctly. My main focus for MonetDB is also the usage of SQL by using a JDBC connection, therefore I hope this isn't a known newbie problem. cheers, Arnold

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[MonetDB-users] bogus SQL in example + bad Mapi error reporting
by Martijn Faassen 03 Jul '05

03 Jul '05

Hi there, I just spent several hours scratching my head over why a piece of code didn't work. I was experimenting with Mapi and tried the example listed on the top of this page: http://monetdb.cwi.nl/TechDocs/APIs/Mapi/C/index.html This contains the following line: if ((hdl = mapi_query(dbh, "create table emp(name varchar, age int)")) == NULL) die(dbh); Unfortunately, it needs to be 'varchar(20)', not just plain 'varchar'. Just 'varchar' apparently does *not* result in an error, but instead all subsequent insert operations plus the select operation do nothing whatsoever; the fetching returns no results at all. The combination of this very bad error reporting and the mistake in the very first example given on the C API page cost me quite a bit of time, so I'm slightly grumpy. :) The bad example given is not good, but the way the error appears to be completely ignored is worse; this is not good for debuggability. The combination is terrible and not particularly conductive to the uptake of MonetDB. It may be of course that this bug is already fixed in CVS; I'm working off the latest release. Anyway, now that my test code finally works, I can hopefully make some progress hooking up XQuery to a Python API. (this is an experiment, and I realize the existing Python Mapi client code already ought to work, but we'll see..). Regards, Martijn

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[MonetDB-users] mapi and xquery
by Martijn Faassen 03 Jul '05

03 Jul '05

Hi there, I'm trying to figure out how to use mapi to do an xquery. I have been able to shred documents (using MIL), but mapi with xquery is giving me trouble. Looking at the implementation of MapiClient, I see the following piece of code which appears relevant: /* xquery options are passed via the command string (becomes first line of query) */ char *c = command ? command : XQuerydefaultMode; char *t = strstr(c, "timing-") ? "" : mark ? "timing-" : ""; char *d = strstr(c, "debug-") ? "" : trace ? "debug-" : ""; char *m = strstr(c, "-mapi") ? "" : "-mapi"; command = (char*) malloc(strlen(c) + 20); sprintf(command, "%s%s%s%s\n", t, d, c, m); as well as this code: if (command) { /* special code for XQuery: prepend command to query */ hdl = mapi_query_prep(mid); CHECK_RESULT(mid, hdl, buf, break); mapi_query_part(hdl, command, strlen(command)); what exactly is going on here? The logic is rather opaque... Is there some minimal code example somewhere out there that shows how to do an xquery using mapi? Regards, Martijn

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[MonetDB-users] xquery collection support?
by Martijn Faassen 02 Jul '05

02 Jul '05

Hi there, Another question: does the xquery implementation have collection support? It appears not, as fn:collection doesn't appear to be supported yet, but I'm a newbie to xquery so I may be missing something. I'm interested in XML content management applications, which tend to keep lots (and lots) of smaller XML documents. It'd be interesting to be able to query all of them (or sets of them) using XQuery in one go -- looping through all the stored documents and doing an XQuery on these individually would be suboptimal. Regards, Martijn

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