- users-list - monetdb.org

[MonetDB-users] sql execution time
by Gerrard_56 09 Jan '10

09 Jan '10

Hi. I would like to compare the performance of MonetDB with the performance of an Oracle DB by using the TPC-H benchmark. I use the MonetDB server v5.14.2 with the MonetDB/SQL module v2.32.2 on a windows xp platform. On the MonetDB website (http://monetdb.cwi.nl/SQL/Benchmark/TPCH/) I read that they used the mclient with the –t argument in order to obtain the timings for the queries. I tried the same but the displayed time for queries which return several 100 rows is very high. For example the TPC-H query nr. 3 with returns 11620 row the time was 13796.174 msec. If I execute the same query in the db visualize it just needs 0.864 sec for the result. I think the problem with the mclient is that it needs a lot of time to display the result of the queries. Is there a better alternative to the –t argument of the mclient to get a useful time result? Thank you for any help Gerrard -- View this message in context: http://old.nabble.com/sql-execution-time-tp27088775p27088775.html Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] Ebuilds for MonetDB
by W-Mark Kubacki 07 Jan '10

07 Jan '10

Hello. I'd like to thank you for MonetDB by providing fresh ebuilds for the suite. And yes, I did find Fabian Groffen's, but they were outdated and removed from main tree. So, find new ones in my Gentoo overlay [1] along with binaries for amd64 and arm on my binhosts [2,3]. Unfortunately Monet features a lot unused configure flags and deviates from the Filesystem Hierarchy Standard (FHS) 2.3 [4] (*), therefore I had to put an extra efford to sieve the first out and have files installed corretly. If you happen to find something I missed, don't hesitate to drop me a line or two. -- Beste Grüße W-Mark Kubacki http://mark.ossdl.de/ [1] http://git.ossdl.de/?p=ossdl-overlay.git;a=summary [2] http://binhost.ossdl.de/x86_64-pc-linux-gnu/ , http://binhost.ossdl.de/x86_64-pc-linux-gnu/Packages [3] http://binhost.ossdl.de/armv5tel-softfloat-linux-gnueabi/ , http://binhost.ossdl.de/armv5tel-softfloat-linux-gnueabi/Packages [4] http://www.pathname.com/fhs/

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[MonetDB-users] vaultkey, embedded, and merovingian.
by Guillaume Yziquel 05 Jan '10

05 Jan '10

Hi. I've been creating a database from a call to monetdb_sql() from libembeddedsql5.so, from my OCaml binding. After that, I start up a merovingian process and I do the following: > yziquel@seldon:~/git/ocaml-monetdb5$ monetdb status > name state uptime health last crash > testdb stopped 100%, 49s - > yziquel@seldon:~/git/ocaml-monetdb5$ monetdb start testdb > starting database 'testdb'... FAILED > start: starting 'testdb' failed: cannot start database 'testdb': no .vaultkey found (did you create the database with `monetdb create testdb`?) I'm quite baffled by the error I just got. What is this .vaultkey problem? All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] Inserting '\' into varchar(1)
by Alex Bo. 04 Jan '10

04 Jan '10

Hi, I think I found a bug: I can't seem to insert the character '\' into Monet with COPY INTO when I use a single character column: 1. I have a text file that only contains this: '1,"\\"' 2. create table test1 (f1 int, f2 varchar(1)) 3. copy into test1 from 'C:\test1.txt' using delimiters ',','\r\n','"' null as ''; I get: SQLException:sql:value '\\' from line 1 field 2 not inserted, expecting type str If I change the field size from varchar(1) to varchar(2) it works. (Aug09 & Nov09 on Windows) Is this a bug? Thanks & happy new year. -- View this message in context: http://old.nabble.com/Inserting-%27%5C%27-into-varchar%281%29-tp27010393p27… Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] Nightly builds are still OK?
by Guillaume Yziquel 04 Jan '10

04 Jan '10

Hi. I've been trying to fetch nightly builds, but on the webpage http://monetdb.cwi.nl/testing/projects/monetdb/Current/.DailyBuilds./ it seems that the last nightly build was one week or so ago. Are nightly builds still working fine? Just to know... All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] Error on "rank() over (order by sum(.."
by Makoto YUI 04 Jan '10

04 Jan '10

Hi, The following query yields "SELECT: subquery result missing" error on Nov2009-SP1. select s_name, sum(score), rank() over (order by sum(score) desc) from score_table group by s_name -- preparation create table score_table ( s_name varchar(20), subject varchar(10), score int ); insert into score_table values('foo','english',70); insert into score_table values('foo','history',50); insert into score_table values('foo','math',60); insert into score_table values('bar','english',45); insert into score_table values('bar','history',75); It seems allowed to use aggregation functions in "over(..)" in other databases. http://www.google.com/search?q="rank()+over+(order+by+sum(" Thanks, Makoto

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[MonetDB-users] Limitation in "create table .. as subquery"
by Makoto YUI 04 Jan '10

04 Jan '10

Hello, create table t1 (f1 int); insert into t1 values (1); insert into t1 values (2); create table t2 as (select * from t1 limit 1) with data; The above "create table" caused the following syntax error on the Limit clause. syntax error, unexpected LIMIT, expecting INTERSECT or EXCEPT or UNION or ')' in: "create table t2 as (select * from t1 limit" Is this an expected behavior? This "subquery" issue might be related. http://sourceforge.net/tracker/?func=detail&atid=482468&aid=2620437&group_i… I'm using Nov2009-SP1 on Linux. Thanks, Makoto

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[MonetDB-users] Problem with BSS initialisation.
by Guillaume Yziquel 04 Jan '10

04 Jan '10

Hello. I've spent quite some time lately debugging my issue with OCaml binding of MonetDB libraries: http://www.mail-archive.com/caml-list@yquem.inria.fr/msg05449.html It seems that the BSS is not properly initialised to 0 when dynamically loaded. It seems that the code in mal_box.c relies on the fact that BSS is initialised to 0 when loaded. I'm still trying to figure out how exactly is the libmonetdb5.so library loaded. This is still an obscure point. ltrace did not provide useful information. Advice welcome. -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] Multiple core usage on Windows
by Alex Bo. 03 Jan '10

03 Jan '10

Hi, Does MonetDB split a single query plan over multiple CPU cores when its possible? (maybe the DataFlow optimizer?) For example, the following query could be executed by all cores in parallel: SELECT field1,SUM(field2) FROM Table1 GROUP BY field1 When i tried to see if it does, i got some weird results: (I am running MonetDB on Windows, on a quad core machine) When I set '--set gdk_nr_threads=1', queries never seem to use more than 25%. (seems logical since only one CPU core is being deployed) When I set '--set gdk_nr_threads=2', queries use up to 50% CPU, but the query is ~15% slower. When I set '--set gdk_nr_threads=4', queries use up to 98% CPU, but the query is take twice as long as with 1 thread. So, my initial assumption that more CPU utilization (more cores over the same query) will result faster query results (where applicable) is wrong. Can it be something specific to the windows platform? or maybe single query execution over multiple cores doesn't work without a specific optimizer flag enabled?... or maybe is it just a bug... Thanks. -- View this message in context: http://old.nabble.com/Multiple-core-usage-on-Windows-tp27002955p27002955.ht… Sent from the monetdb-users mailing list archive at Nabble.com.

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Re: [MonetDB-users] segfault with monetdb_sql().
by Guillaume Yziquel 02 Jan '10

02 Jan '10

Martin Kersten a écrit : >>> >>> Program received signal SIGSEGV, Segmentation fault. >>> [Switching to Thread 0x2aaaaf66d910 (LWP 4061)] >>> 0x00002aaaac676de3 in findBox () from /usr/lib/libmonetdb5.so.5 > > i miss here the line number, seems that is ubunti specific > you can do > print i > print box[i] > print name Providing debian packages of libraries with debugging symbols would be great. > i suspect box[i] is not properly initialized to 0 I'll try to check that. >>> (gdb) backtrace >>> #0 0x00002aaaac676de3 in findBox () from /usr/lib/libmonetdb5.so.5 > this gives one hint, it is likely passed without name causing idcmp to fail >>> #1 0x00002aaaac677086 in openBox () from /usr/lib/libmonetdb5.so.5 >>> #2 0x00002aaab7a51cbb in MTIMEprelude () from > > happens while loading the data/time module. It initializes the "time" > module Should I assume that the mtime.mal + lib_mtime.so is the first one to be loaded? Just to know if some dynamic linking successfully happened before or not. >>> /usr/lib/MonetDB5/lib/lib_mtime.so >>> #3 0x00002aaaac6826cf in ?? () from /usr/lib/libmonetdb5.so.5 >>> #4 0x00002aaaac68b2a0 in runMAL () from /usr/lib/libmonetdb5.so.5 >>> #5 0x00002aaaac67cac7 in MALengine () from /usr/lib/libmonetdb5.so.5 >>> #6 0x00002aaaac67d5f6 in malBootstrap () from /usr/lib/libmonetdb5.so.5 >>> #7 0x00002aaaac669f75 in mal_init () from /usr/lib/libmonetdb5.so.5 >>> #8 0x00002aaaab91ef60 in ?? () from /usr/lib/libembeddedsql5.so >>> #9 0x00002aaaab39b73a in start_thread () from /lib/libpthread.so.0 >>> #10 0x00002aaaab67c69d in clone () from /lib/libc.so.6 >>> #11 0x0000000000000000 in ?? () >>> (gdb) >> >> Please tell me what else could be useful. > > This was already useful, because i added two additional defense lines > to capture improperly set environments. OK. I'll check. >>> I am not an CAML expert, but i guess there may be potential issues >>> in location and dynamic loading of the necessary libraries. >>> Where does CAML get the libraries from? >> >> As a rather general statement, dynamic loading is supported within >> OCaml world. I'm not so sure how this works when it is C code that >> triggers dynamic loading, with OCaml in bytecode mode... > > I have added some extra code to make failing loads more visible. > In general, it seems that the modules are not found at the location I'll ask on the OCaml list for that. >> I would like to pinpoint the segfault more precisely in order to go >> back to the OCaml mailing list about potential dynamic loading issues. > I think it can not find your libraries > > set the variable gdk_debug=10 this will show you the environment > settings as seen upon start. Including the location where it expect > database and libraries to recide. Will do that. However, I believe it is not a problem of location, as this works out fine when the OCaml binding is compiled to native code. All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] (no subject)
by Zoltan Tomory 30 Dec '09

30 Dec '09

Hi everybody, Forgive the reference to a cartoon, but it seems strangely on topic ... >There's a wonderful comic strip on the web called xkcd; I don't know if you've heard of it. I have to share this one with you. It's called "Exploits of a mother": > >http://xkcd.com/327/ Happy New Year! Zoltan Tomory zoltan.tomory(a)mobot.org

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Re: [MonetDB-users] segfault with monetdb_sql().
by Guillaume Yziquel 29 Dec '09

29 Dec '09

Hello. As some discussion had gone off-list, here's some relevant background: The OCaml binding works when the OCaml library is compiled to native code, and it segfaults when the OCaml library is compiled to bytecode. Martin Kersten a écrit : > > What is the gdb stack trace of the processes involved? segfaults are only > analysed that way. Quite new to gdb, so I do not know if this is what you've asked for: > gdb --args ocamlrun test/monetdb_sql.byte > GNU gdb (GDB) 7.0-debian > Copyright (C) 2009 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> > This is free software: you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > and "show warranty" for details. > This GDB was configured as "x86_64-linux-gnu". > For bug reporting instructions, please see: > <http://www.gnu.org/software/gdb/bugs/>... > Reading symbols from /usr/bin/ocamlrun...(no debugging symbols found)...done. > (gdb) run > Starting program: /usr/bin/ocamlrun test/monetdb_sql.byte > [Thread debugging using libthread_db enabled] > [New Thread 0x2aaaaf66d910 (LWP 4061)] > > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0x2aaaaf66d910 (LWP 4061)] > 0x00002aaaac676de3 in findBox () from /usr/lib/libmonetdb5.so.5 > (gdb) backtrace > #0 0x00002aaaac676de3 in findBox () from /usr/lib/libmonetdb5.so.5 > #1 0x00002aaaac677086 in openBox () from /usr/lib/libmonetdb5.so.5 > #2 0x00002aaab7a51cbb in MTIMEprelude () from /usr/lib/MonetDB5/lib/lib_mtime.so > #3 0x00002aaaac6826cf in ?? () from /usr/lib/libmonetdb5.so.5 > #4 0x00002aaaac68b2a0 in runMAL () from /usr/lib/libmonetdb5.so.5 > #5 0x00002aaaac67cac7 in MALengine () from /usr/lib/libmonetdb5.so.5 > #6 0x00002aaaac67d5f6 in malBootstrap () from /usr/lib/libmonetdb5.so.5 > #7 0x00002aaaac669f75 in mal_init () from /usr/lib/libmonetdb5.so.5 > #8 0x00002aaaab91ef60 in ?? () from /usr/lib/libembeddedsql5.so > #9 0x00002aaaab39b73a in start_thread () from /lib/libpthread.so.0 > #10 0x00002aaaab67c69d in clone () from /lib/libc.so.6 > #11 0x0000000000000000 in ?? () > (gdb) Please tell me what else could be useful. > I am not an CAML expert, but i guess there may be potential issues > in location and dynamic loading of the necessary libraries. > Where does CAML get the libraries from? As a rather general statement, dynamic loading is supported within OCaml world. I'm not so sure how this works when it is C code that triggers dynamic loading, with OCaml in bytecode mode... I would like to pinpoint the segfault more precisely in order to go back to the OCaml mailing list about potential dynamic loading issues. > We can help (on Xmas days) only with proper output. The level of > programming > calls for expertise in dealing with C debuggers, dynamic loaders, and > thread > management. Guessing does not bring us further. You have to use the > right tools. OK. This is always a good opportunity to learn more about C world... Thanks for pointing out the right tools. All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] Instalation prob. in Ubuntu
by Rui Anastácio 28 Dec '09

28 Dec '09

Hi, I'm trying to install monetdb in my Linux Ubuntu 9.10 Karmik and have followed the instructions but have this dependency problem: monetdb-geom-dev: Depends: libmonetdb5-geom0 not installable monetdb-testing: Depends: python-monetdb not installable Regards Rui Anastácio

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[MonetDB-users] Updating a single column by means of a secondary table
by Stefan de Konink 27 Dec '09

27 Dec '09

Hi, I have the following issue; I would like to update a new column with respect to old data. In essence this would be the idea that I want to do: update anbikvk set intrekking = (select intrekking from anbi_update where anbi_update.naam = anbikvk.naam); The above way does not work, the only other way that I would know would involve a temporary table. Could anyone elaborate how this is possible using the update statement? Stefan

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[MonetDB-users] segfault with monetdb_sql().
by Guillaume Yziquel 27 Dec '09

27 Dec '09

Hello. I've been having segfaults when using the following wrapper code. (Do not pay attention to the CAML* macros, and String_val is a macro that converts a string in OCaml to a C string, and Val_ptr is a function that wraps up a pointer into OCaml.) > CAMLprim value ml_monetdb_sql (value ml_dbfarm, value ml_dbname) { > CAMLparam2(ml_dbfarm, ml_dbname); > CAMLlocal1(result); > char * dbfarm; > char * dbname; > dbfarm = String_val(ml_dbfarm); > dbname = String_val(ml_dbname); > Mapi mapi = monetdb_sql(dbfarm, dbname); > result = Val_ptr(mapi); > CAMLreturn(result); > } I'm calling this code with dbfarm and dbname set to a place I can write to, and that does not contain folders, files, or data at the time the function is called from OCaml code. When executing the following piece of code from the OCaml toplevel > #use "topfind";; > #thread;; > #load "monetDB5.cma";; > > open MonetDB5;; > let mapi = monetdb_sql "/home/yziquel/sandbox/monetdb" "testdb";; I get a segfault arising from monetdb's shared libraries (I'm using the Debian packages on a 64 bits platform): > yziquel@seldon:~/git/ocaml-monetdb5$ ocaml -init ocamlinit > Objective Caml version 3.11.1 > > Findlib has been successfully loaded. Additional directives: > #require "package";; to load a package > #list;; to list the available packages > #camlp4o;; to load camlp4 (standard syntax) > #camlp4r;; to load camlp4 (revised syntax) > #predicates "p,q,...";; to set these predicates > Topfind.reset();; to force that packages will be reloaded > #thread;; to enable threads > > /usr/lib/ocaml/threads: added to search path > /usr/lib/ocaml/unix.cma: loaded > /usr/lib/ocaml/threads/threads.cma: loaded > Erreur de segmentation Here at the last line... Looking at the code in monetdb-sql-2.34.2/src/backends/monet5/embeddedclient.c.in I'm unable to determine if the segault comes from the invocation of pthread_create or from the invocation of mapi_start_talking. > Mapi > monetdb_sql(char *dbfarm, char *dbname) > { > Mapi mid; > pthread_t sqlthread; > stream **server; > > int len = mo_builtin_settings(&embedded_set); > > /* needed, to prevent the MonetDB config file to be used */ > len = mo_add_option(&embedded_set, len, opt_config, "prefix", MONETDB5_PREFIX); > len = mo_add_option(&embedded_set, len, opt_config, "config", MONETDB5_CONFFILE); > len = mo_add_option(&embedded_set, len, opt_config, "monet_mod_path", > "@QXlibdir@@QDIRSEP@MonetDB5@PATHSEP@@QXlibdir@@QDIRSEP@MonetDB5@QDIRSEP@lib@PATHSEP@@QXlibdir@@QDIRSEP@MonetDB5@QDIRSEP@bin"); > > embedded_len = mo_system_config(&embedded_set, len); > embedded_len = mo_add_option(&embedded_set, embedded_len, opt_cmdline, "gdk_dbfarm", dbfarm); > embedded_len = mo_add_option(&embedded_set, embedded_len, opt_cmdline, "gdk_dbname", dbname); > > server = mapi_embedded_init(&mid,"sql"); > > pthread_create(&sqlthread, NULL, start_sql_server, (void *) server); > > mapi_start_talking(mid); > > return mid; > } Could someone give me hints as to what is going wrong here? All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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Re: [MonetDB-users] mserver5 crashed after 10, 000 times sql queries through JDBC interface
by xulizhong 26 Dec '09

26 Dec '09

> Could you provide the query and schema? CREATE TABLE STOCKINFO ( STOCK_ID INTEGER NOT NULL, STOCK_CODE VARCHAR(30), EX_CODE VARCHAR(30), SH_CODE VARCHAR(30), LONGNAME_CN VARCHAR(50), SHORTNAME_CN VARCHAR(30), EX_ID INTEGER NOT NULL, CSRC_CAT INTEGER DEFAULT NULL, SW_CAT INTEGER DEFAULT NULL, SH_CAT INTEGER DEFAULT NULL, HAS_DETAIL BOOLEAN DEFAULT NULL, BG_CODE VARCHAR(20), IPO_TIME DATE DEFAULT NULL, BOARD_CAT INTEGER DEFAULT NULL, IS_ST BOOLEAN DEFAULT NULL, HAS_OPTION BOOLEAN DEFAULT NULL, CURRENCY INTEGER DEFAULT NULL, CARRY INTEGER DEFAULT NULL, DECIMALS INTEGER DEFAULT NULL, MIN_PRICE_CHANGE DOUBLE DEFAULT NULL, STOCK_CAT INTEGER DEFAULT NULL, SURGED_LIMIT DOUBLE DEFAULT NULL, DECLINE_LIMIT DOUBLE DEFAULT NULL, HIGH_52WK INTEGER DEFAULT NULL, LOW_52WK INTEGER DEFAULT NULL ); query: SELECT STOCK_ID FROM STOCKINFO WHERE LOW_52WK<85 and HIGH_52WK>110 and EX_ID=15 AND IPO_TIME>'2000-1-1' AND STOCK_CODE LIKE '1%'; I write a simple java program using 4 threads to execute this query with a connection pool of 4 max active connections. The mserver5 process' memory increase steadily upto 2.5G, then the process crashes with segmentation fault:( I have noticed something special, when I run the query using : ResultSet result = conn.prepareStatement(sql).executeQuery(); the monetdb5 server will consume large amount of memory and crash definitely. However, when I query using: ResultSet result = conn.createStatement().executeQuery(sql); the server's memory usage is very stable. This may indicate there's something wrong with the prepared statement of the sql module of MonetDB5. Below is my test program: ////////////////////////////////////////////////////////// import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.util.Date; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; import org.apache.commons.dbcp.BasicDataSource; public class MonetBenchmark { /** * @param args */ public static void main(String[] args) { ExecutorService executor = Executors.newFixedThreadPool(4); final BasicDataSource dataSource = new BasicDataSource(); dataSource.setMaxActive(4); dataSource.setInitialSize(4); dataSource.setDriverClassName("nl.cwi.monetdb.jdbc.MonetDriver"); dataSource.setUrl("jdbc:monetdb://localhost/demo"); dataSource.setUsername("monetdb"); dataSource.setPassword("monetdb"); final String sql = "SELECT STOCK_ID FROM STOCKINFO WHERE LOW_52WK<85 and HIGH_52WK>110 and EX_ID=15 AND IPO_TIME>'2000-1-1' AND STOCK_CODE LIKE '1%';"; System.out.println("running ... " + new Date());; long start = System.currentTimeMillis(); int loop = 10000; for (int x = 0; x < loop; x++) { executor.submit(new Runnable() { public void run() { Connection conn = null; try { conn = dataSource.getConnection(); ResultSet rs = conn.createStatement().executeQuery(sql); //using prepared statement will cause the server crashed with segmentation fault and very big memory usage. // ResultSet rs = conn.prepareStatement(sql).executeQuery(); while(rs.next()) { //... } } catch (SQLException e) { e.printStackTrace(); } finally { try { conn.close(); } catch (Exception e) { } } } }); } try { executor.shutdown(); executor.awaitTermination(5, TimeUnit.MINUTES); } catch (InterruptedException e) { e.printStackTrace(); } long time = System.currentTimeMillis() - start; System.out.println(time + " ms for " + loop + " times query! " + (time / loop) + " ms/q"); } } And my last question, is this newest version of MonetDB suitable for production use if I always use normal jdbc statement to execute my query? Thanks alot.

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[MonetDB-users] OCaml binding for embedded MonetDB5.
by Guillaume Yziquel 24 Dec '09

24 Dec '09

Hello. I would like to create a binding for the Objective Caml language of an embedded MonetDB5. My personal focus would be on embedded_mal, but I'm perfectly willing to get started on embedded_sql. I've been looking at some documentation, which I unfortunately find rather terse. For instance: http://monetdb.cwi.nl/MonetDB/Documentation/A-Simple-Example.html I'm, for example, wondering about the semantics of the embedded_sql function whose code from embeddedclient.c.in is reproduced below. > Mapi > embedded_sql(opt *set, int len) > { > Mapi mid; > pthread_t sqlthread; > stream **server; > > if (set) { > embedded_set = set; > embedded_len = len; > } > server = mapi_embedded_init(&mid,"sql"); > > pthread_create(&sqlthread, NULL, start_sql_server, (void *) server); > > mapi_start_talking(mid); > > return mid; > } I'd therefore like to know if there is some piece of documentation (aside the code itself) where I could gain a deeper understanding of what I want to wrap up and bind. Links appreciated. -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] monetdb program in debian packages?
by Guillaume Yziquel 24 Dec '09

24 Dec '09

Hello. I've been trying to follow section 1.78.1 Start and Stop the Server of the manual for MonetDB 5, and I fail to find the monetdb program in the available debian packages. Which package should I install to be able to launch the monetdb program as in section 1.78.1? All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] mserver5 crashed after 10, 000 times sql queries through JDBC interface
by xulizhong 24 Dec '09

24 Dec '09

I'm using the latest MonetDB5: MonetDB-Nov2009-SuperBall-SP1 on Red Hat Enterprise Linux AS release 4 (Nahant Update 4) x86_64. dependencies: openssl-0.9.8l, pcre-8.00. The box has 8G physical memory, about half of them is available. building options: ./monetdb-install.sh --prefix=/opt/monetdb5 --enable-sql --enable-optimise After installation, I started the mserver5 process: /opt/monetdb5/bin/mserver5 --dbinit "include sql;", then I load one table exported from MySQL with about 1M rows and 20 columns. I noticed small memory increase when I run a simple query on the mclient console for some times. So I run this query through the JDBC interface for 10000, I can see a big memory consumption rise when the test program is running. and finally the mserver5 process crashed with segmentation fault. I can always reproduce this problem. What's wrong? Have I used some wrong build options? Help! Frank

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[MonetDB-users] Fatal error: aborted too deep recursion
by Harm van Beek(DT) 24 Dec '09

24 Dec '09

During the development of our tool, using Xquery on MonetDB, we ran onto the following error: ERROR = !fatal error: aborted too deep recursion >From previous posts (I guess) I can conclude that this relates to an Xquery that simply is too big (too many operators) to create a good plan for it. I tried several MonetDB releases (May2009-SP2, Aug2009-SP2, Nov2009-DB0) on Red Hat Enterprise Linux Server release 5.4 (Tikanga), all showing the same result. Does anyone have any directions on how to solve this? Can we reconfigure the compiler to fix this (or recompile it with options)? Thanks in advance! Harm van Beek Netherlands Forensic Institute

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[MonetDB-users] man page for debian package.
by Guillaume Yziquel 23 Dec '09

23 Dec '09

Hi. Just a simple suggestion: I'm using the Debian package for MonetDB v5, and have just started tinkering with it. One thing I really like is a man page. It would be nice to have one. Not necessarily an exhaustive one, but one that would comment the mserver5 options a bit more clearly than mserver5 --help, and which would provide pointers to documentation. Finding documentation on monetdb wasn't easy. Writing good documentation is a painful task, but providing pointers to documentation within a man page is much easier... All the best, -- Guillaume Yziquel http://yziquel.homelinux.org/

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[MonetDB-users] Memory Usage
by Rui Anastácio 23 Dec '09

23 Dec '09

Hi ! I'm runnig MonetDB under Linux Ububtu with 4Gb of RAM. I need to benchmark it running 1Gb, 2Gb, 3Gb and 4Gb. Todo so I need to limit the memory usage. How can I configure MonetDB to limit it's memory usage? and doing so am I able to run complex queries (with short memory) ? Regards Rui Anastácio

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[MonetDB-users] MonetDB scalability
by Bojan Šmid 22 Dec '09

22 Dec '09

Hi, I am thinking of using MonetDB as a data storage for my application. The application will create lots of data (few GB of new data each day) while there will not be many queries (probably few thousands/day). Queries will be complex, but they should execute really fast. Since data will grow pretty fast, I must prepare for scaling, so I need to know is there a way to distribute MonetDB over multiple machines? Thanks and regards

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Re: [MonetDB-users] MonetDB scalability
by OG 22 Dec '09

22 Dec '09

Hello, Somebody on this list asked about scalability the other day: http://markmail.org/message/2unmuwq2cfz7mrmm I was wondering the same thing. Is there a way to partition/shard MonetDB and still have joins work across partitions living on separate servers? If not, is there a recommended practice for what to do with MonetDB once the limit of a single server has been reached? Thanks, Otis -- Sematext -- http://sematext.com/ -- Solr - Lucene - Nutch

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[MonetDB-users] UTF-8 for table/column names
by Alex Bo. 22 Dec '09

22 Dec '09

Hi, Is there support for UTF8/Unicode for field/table names? It seems like i can only use ASCII characters (for example, a field name with specific Spanish letters wouldn't work) inside field/table names. I'm using the Nov09 on Windows. Thanks. -- View this message in context: http://old.nabble.com/UTF-8-for-table-column-names-tp26888868p26888868.html Sent from the monetdb-users mailing list archive at Nabble.com.

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