November 2009 - users-list

[MonetDB-users] Proofreading your professional documents
by Richard Hounslow 24 Feb '24

24 Feb '24

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[MonetDB-users] Meaning of: Scenario not initialized 'sql'
by Alex Bo. 17 Jun '10

17 Jun '10

Hi, Sometimes I get !MALException:setScenario:Scenario not initialized 'sql' from the server when I try to start it in scenarios that usually work without any problems. I can't reproduce it consistently, but sometimes I get it. What does this exception mean? Thanks. -- View this message in context: http://www.nabble.com/Meaning-of%3A-Scenario-not-initialized-%27sql%27-tp26… Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] Parallel Processing
by Nafees Ur Rehman 04 May '10

04 May '10

Hi, Does monetdb has support for parallel processing? If some can guide me on that. Regards Nafees Ur Rehman

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[MonetDB-users] ubuntu server installation / php modules
by dariuszs 29 Mar '10

29 Mar '10

Hi, I've installed monetdb on *Ubuntu 9.04 Server* with apt-get. These are the contents of php client /. /usr /usr/share /usr/share/doc /usr/share/doc/php5-monetdb-client /usr/share/doc/php5-monetdb-client/changelog.Debian.gz /usr/share/doc/php5-monetdb-client/copyright I need the moduels, where are they? Thanks. Dariusz.

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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] Announcement: New Nov2009 feature release of MonetDB suite
by Stefan Manegold 29 Nov '09

29 Nov '09

Dear all, The MonetDB team at CWI/MonetDB BV are pleased to announce the new "Nov2009" feature release of the MonetDB suite of programs. This feature release is backward compatible with the previous releases (Nov2008 through Aug2009-SP2). Caveat 1: In MonetDB/XQuery, we extended and improved the use of value indices on comparisions between a value and an XPath ending in text() or attribute access (e.g., doc(x)//x/y[z/text() = "foo"] and for $x in doc//x/y where $x/@z = "bar" return $x); such queries do not need scanning data, but start at the index and navigate backwards from there. This required a change in the physical database storage. While the Nov2009 release of MonetDB/XQuery can still read older (pre-Nov2009) databases, it is recommended to (back-up and) re-shred all documents to benefit from the new indices and achieve optimal performance. Caveat 2: When upgrading from a release older than May2009 (i.e., Nov2008 through Feb2009-SP2), you need to move your write-ahead log following the "recommended" instructions for SQL (<http://monetdb.cwi.nl/Development/Releases/May2009/#SQL>) and/or XQuery (<http://monetdb.cwi.nl/Development/Releases/May2009/#XQuery>). More information on the new release is available at <http://monetdb.cwi.nl/Development/Releases/Nov2009/>. The sources and binaries are available at <http://monetdb.cwi.nl/Download/>. Enjoy! The MonetDB team at CWI/MonetDB BV. -- | 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 |

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[MonetDB-users] SABAOTHgetMyStatus Too many open files
by Matthew Jones 28 Nov '09

28 Nov '09

Hey Folks, we are continuing to get deadlocks about once a day and I've noticed this in the logfile: 2009-11-28 14:31:05 ERR reporting_primary[31485]: !SABAOTHgetMyStatus: IOException:sabaoth.getStatus:Unable to open directory /opt/MonetDB5/dbfarm: Too many open files Not sure how many open files it had when it went south, but immediately after a restart I saw this in files-nr: # cat /proc/sys/fs/file-nr 1408 0 3164775 That third number being the 'files-max' on the system currently... I think that must be being dynamically set. This is with the latest release August2009-SP2, the net effect is a deadlock on all connections to merovingian and a segfault of the mserver process. Neils, this is what led up to that 'log' file being truncated in sql_logs a few days ago... this message occurred just before this happened. I've restarted my database and should see the problem reproduce itself again within 24 hours. I am recording the number of file descriptors in use every minute by mserver, merovingian, and overall for the system so I can know what the numbers were leading up to it. Is this a file descriptor leak in Monet or is my files-max set too low (even though it appears to be dynamic)? 73, Matthew W. Jones (KI4ZIB) http://matburt.net

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[MonetDB-users] COPY INTO memory issues
by Andreas Streichardt 26 Nov '09

26 Nov '09

Hi, i had a look at monetdb a while (a year or so) ago and stumbled upon a few crashes/memory issues back then. Apart from that it made a very promising impression to me. Today i thought i could give it a try again to see if these issues have been fixed and found out that copy into still seems to have memory issues and i wonder if i am the only one who hits such issues. I am experimeting with dummy data created by a script. Data is created the following way: 20 smallints: Values 1-10. 100 tinyints: Values 0-1 20 ints: Values 1-10000 40 varchars: md5 of some random value 20 floats: rand(1000000)/1000000 I created a CSV file with ~2.1 million rows and then tried to insert the data. My first attempt was: sql>copy into md_data FROM '/home/mop/performance/hans.csv' delimiters ',','\n' null as ''; MAPI = monetdb@localhost:50000 ACTION= read_line QUERY = copy into md_data FROM '/home/mop/performance/hans.csv' delimiters ',','\n' null as ''; ERROR = Connection terminated This was of course the quick and dirty way. What happened in the background was that monetdb consumed all memory. My system is a debian lenny 64bit. Server has 4GB and decent CPUs. Why does it need all my memory here? I then did the same but loaded only parts of the file (1000000 rows). sql>copy 1000000 records into md_data FROM '/home/mop/performance/hans.csv' delimiters ',','\n' null as '' ; This worked but the server used ~2-3GB of my RAM during the process and what's even more important it used the same amount even though the copy process finished. Why does it use the RAM even though it is not used anymore? Then i tried to insert 1000000 rows more and my expectation was that monetdb would reuse the memory it allocated (and didn't free) in the first loading process. This wasn't the fact. Again monetdb consumed all my memory and when loading finished it indicated that it was still doing something (CPU @ ~20%). When i tried a: sql>SELECT COUNT(*) FROM md_data; it hang completely. Same when trying to establish a new connection. I stopped the server and restarted again. Everything was fine again. I inserted the rest of the data (memory raised again but there were only 100000 rows left so there wasn't any problem this time). Am i the only one hitting such issues? One could argue that i should import less records at once but even then. There seems to be some nasty memleak in the background. Or is this a configuration issue? Or am i doing something completely wrong? I am using the .debs: http://monetdb.cwi.nl/downloads/Debian/ Thanks in advance, Andreas Streichardt

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Re: [MonetDB-users] COPY INTO memory issues
by Jens Oehlschlägel 25 Nov '09

25 Nov '09

> > This wasn't the fact. Again monetdb consumed all my memory and when loading > > finished it indicated that it was still doing something (CPU @ ~20%). > log records have to be written, your OS may kick in to flush dirty pages, > reloading swapped out processes, .... The following might not apply to Linux, but still: under windows, suddenly flushing dirty pages from large memory mapped files can severly degrade the system performance ("stalled"). I know windows has settings to limit the amount of dirty pages that may accumulate without flushing. Maybe Linux has something similar and maybe this helps here. Please keep me in the loop if you try this route. Jens

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[MonetDB-users] 'create table as select...' from union queries doesn't work
by Alex Bo. 25 Nov '09

25 Nov '09

Hi, If I do this: create table t1 (f1 int); create table t2 (f1 int); create table t_union as (select f1 from t1 union all select f1 from t2) with data; Then no table is created and no exception is thrown. Should I open a bug for this? (AugSP2 on Windows) -- View this message in context: http://old.nabble.com/%27create-table-as-select...%27-from-union-queries-do… Sent from the monetdb-users mailing list archive at Nabble.com.

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