May 2008 - users-list

[MonetDB-users] MonetDB as server side environment
by bryan rasmussen 18 May '08

18 May '08

Hi, I'm thinking about moving some applications I have running in eXist to MonetDB, just to gauge performance and possibilities. These applications take parameters from the querystring, is there an example of accessing the querystring in a MonetDB Xquery XQL file when it runs? Best Regards, Bryan Rasmussen

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[MonetDB-users] MonetDB V 4.22 installation on Mac OS X 10.5.2 and Mac OS X 10.4.0.
by Irini Fundulaki 16 May '08

16 May '08

Hi, I have the following problems with MonetDB XQuery Release Feb 2008, V. 4.22 on Mac OS X 10.5.2 and Mac OS X 10.4.0. 1) Mac OS X 10.5.2: a) I was not able to install MonetDB from sources. I downloaded MonetDB-Feb2008-SuperBall.bz2 and followed the instructions in http://monetdb.cwi.nl/projects/monetdb//MonetDB/Documentation/Linux-Install…. I successfully installed MonetDB, clients and MonetDB4-server, but when installing MonetDB4-XQuery I had the following error: Undefined symbols: "_embedded_mil", referenced from: _main in prog.o ld: symbol(s) not found collect2: ld returned 1 exit status make[5]: *** [Mbeddedxq] Error 1 make[4]: *** [all] Error 2 make[3]: *** [all-recursive] Error 1 make[2]: *** [all] Error 2 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 b) by calling monetdb-install.sh. MonetDB was installed with no problems. Nevertheless, mclient with a simple query (e.g., <example>hello</example) stalled. Mserver stalled when executing xmldb_print(); 2) Mac OS X 10.4.0 a) I was able to install MonetDB XQuery Release Feb 2008, V. 4.22 using monetdb-install.sh. Mserver did not stall with xmldb_print(). mclient for the same query exhibited different behaviors: that is, sometimes it stalled, and others not (again, the same simple query as before). I had downloaded MonetDB on September 2007, and installed it on Mac OS X 10.4.0. I had no problem with that version. Thanks for looking into it, Irini

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[MonetDB-users] multi-query optimization?
by Chinyi Woo 16 May '08

16 May '08

Hello, I have a set of xqueres, which need to be run against a xml doc. In my xqueries, there are many common subexpressions. May I ask you whether MonetDB does any multi-query optimization, or the current version of MonetDB runs them sequentially? Thanks Chinyi

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[MonetDB-users] question about composite uniqueness constraints
by Drew Sky 15 May '08

15 May '08

Hi, I have a question about creating composite uniqueness constraints in monetdb. Say I create the following table called test_property with 3 columns: subject, p1, p2. I want uniqueness contraints for each pair of (subject, p1) and (subject, p2). I try to do this with the following: sql>create table test_property(subject integer, p1 integer, p2 integer, unique(subject, p1), unique(subject, p2)); sql>\d test_property CREATE TABLE "sys"."test_property" ( "subject" int, "p1" int, "p2" int, CONSTRAINT "test_property_subject_p2_unique" UNIQUE ("subject"), CONSTRAINT "test_property_subject_p1_unique" UNIQUE ("subject", "p2", "p1") ); But somehow, I end up with a constraint on "subject" by itself and one on ("subject", p2, p1). Is this a bug in monetdb or am I missing something? I ran the exact same commands in postgres and I got my expected results (2 uniqueness contraints on (subject, p1) and (subject, p2)). I tried also creating the table first, then adding columns and the uniqueness constraint after using ALTER TABLE, but I got the same results. Does anyone see something I'm doing wrong? Thanks Andrew

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[MonetDB-users] Space measurement and data compression in monetdb
by Iftikharn 15 May '08

15 May '08

I have two queries regarding monetdb: Is it possible to measure that how much space/memory each table has occupied? and Is is possible to compress the data (by using a command...)? Regards, Iftikhar -- View this message in context: http://www.nabble.com/Space-measurement-and-data-compression-in-monetdb-tp1… Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] broken links on prepared queries
by Chinyi Woo 14 May '08

14 May '08

Hello I have a set of xqueries and want to convert all of them into prepared queries for better performance. I want to see several concrete examples to know how to do this. However, the link at http://monetdb.cwi.nl/XQuery/Version4/Documentation/PreparedQueries/q.xq and http://monetdb.cwi.nl/XQuery/Version4/Documentation/PreparedQueries/m.xq are broken. Could anyone please fix it? thanks Chinyi

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[MonetDB-users] How to measure the performance of a SQL query
by Allan12 14 May '08

14 May '08

How could we measure the performance of a SQL query. I have a table with 100,000 rows and if I peform a SQL query on it, what statistical data I could get. -- View this message in context: http://www.nabble.com/How-to-measure-the-performance-of-a-SQL-query-tp17227… Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] SQL Query performance
by Allan12 14 May '08

14 May '08

How could we measure the performance of a SQL query. I have a table with 100,000 rows and if I peform a SQL query on it, what statistical data I could get in addition to time. -- View this message in context: http://www.nabble.com/SQL-Query-performance-tp17227222p17227222.html Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] How could I run a set of XQuery in a batch?
by Chinyi Woo 14 May '08

14 May '08

Hello, everyone May I ask you how to run a set of XQueries in a batch? I am using MonetDB v4.22.0 on Redhat Linux. I have a set of XQueries. I want to run them against a single xml document and collect the running time. Currently I am only able to submit one XQuery at a time at the mclient commandline. Is there anyway for me to send all my XQueries in a batch and get the total running time? I also have another question. Does MonetDB handle multi-query optimization? I mean if more than one query have common subexpressions, will MonetDB evaluate them just once? Thanks in advance. Chinyi

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[MonetDB-users] A sanity check on MondetDB/XQuery performance
by Nils Grimsmo 13 May '08

13 May '08

Using the "super-ball" from February. I am running some queries, and just want to check if my performance is sane. Are there more indexes I can ask to get built to increase performance? I don't ask for an accurate verification, just a hint of whether or not we are within an order of magnitude of what seems right :) $ Mserver --dbinit="module(pathfinder);" --set mapi_port=60000 $ echo 'pf:add-doc("path/dblp.xml", "dblp.xml")' | mclient --lx -p60000 --time Timer 73068.138 msec $ echo 'pf:documents()' | mclient -lx -p60000 <document updatable="false" url="path/dblp.xml" collection="dblp.xml">dblp.xml</document> $ cat dblp_q7.xq count(doc("dblp.xml")/dblp/*[author="Michael Stonebraker" and author="Hector Garcia-Molina" and year > 1950 ]/title) $ mclient -lx -p 60000 --time < dblp_q7.xq 4 Timer 15512.186 msec (Repeated multiple times for warm-up) My dblp.xml is 441 MB. Mserver uses 1.9 of 3.4 GB memory. $ cat /proc/cpuinfo <snip> model name : AMD Athlon(tm) 64 Processor 3500+ cpu MHz : 2210.763 cache size : 512 KB The dbfarm resides on a WD740GD (http://techreport.com/articles.x/6390). Klem fra Nils

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