May 2009 - users-list

[MonetDB-users] alter table - rename?
by dariuszs 28 May '09

28 May '09

Hi, How do you rename table? Thanks. Dariusz.

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Re: [MonetDB-users] Query plans
by Peter Boncz 25 May '09

25 May '09

Anthony, Suppose you installed MonetDB in the default directory, and have a directory c:\tmp with in it xquery c:\tmp\q.xq, then open a dos box and type (ignoring the prompt>): prompt> cd c:\Program Files\CWI\MonetDB4\bin prompt> set PATH=%PATH%;c:\Program Files\CWI\MonetDB4\lib\ prompt> pf c:\tmp\q.xq The plan you now see on your screen is a low-level physical binary table algebra (MIL) plan. This is what MonetDB executes in the end. The "pf" command is a standalone tool that invokes the "pathfinder" xquery compiler (www.pathfinder-xquery.org), that is integrated in MonetDB/XQuery. It provides many options (see: pf -H). Alternative things to try if you want to undertand query plans: prompt> pf -cPs15 c:\tmp\q.xq prompt> pf -lDs18 c:\tmp\q.xq prompt> pf -pDs20 c:\tmp\q.xq The first one prints the "XQuery Core" representation. At that stage, the query is still formulated in xQuery, but minimized to the subset defined in the XQuery Formal Semantics spec by W3C. The second one produces a logical relational algebra query plan, the third the physical relational algebra plan. Both are a more classical relational algebra (in the database textbook sense), these are intermediate stages the query goes through in the pathfinder. To understand these better, you would probably need to read some papers on MonetDB/XQuery and pathfinder (see the publication library). The last two commands produce output in the "dot" format, you can visualize these with dotty.exe. To do so, download and install the graphviz package (http://www.graphviz.org/Download.php) and make sure the location of "dotty.exe" is in your PATH. Then the following works: prompt> pf -pDs20 c:\tmp\q.xq > c:\tmp\ prompt> dotty c:\tmp\q.dotty (you can resize the screen, and use the menu under the right mouse buttom to zoom in) Peter PS Even though MonetDB/XQuery does not use it, you can even translate xqueries to SQL (to be executed on DB2 only, it does not work on MonetDB/SQL or other systems AFAIK): prompt> pf -Sc:\tmp\q.xq From: Anthony Gkountintas [mailto:agkount@hotmail.com] Sent: Monday, May 25, 2009 10:55 AM To: monet Subject: Query plans Hi all, Is there a possibility to view the xquery execution plans in MonetDb? I am running XQueries on windows platform. thanks Tony ________________________________________ Share your photos with Windows Live Photos – Free. Try it Now! Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 8.5.238 / Virus Database: 270.12.23/2106 - Release Date: 05/09/09 06:54:00

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Re: [MonetDB-users] Query plans
by Peter Boncz 25 May '09

25 May '09

correction: ..... > Then the following works: > prompt> pf -pDs20 c:\tmp\q.xq > c:\tmp\ prompt> pf -pDs20 c:\tmp\q.xq > c:\tmp\q.dotty > prompt> dotty c:\tmp\q.dotty

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[MonetDB-users] Mapi connection hangs
by Alex Bo. 24 May '09

24 May '09

Hi, I reached a certain state where there's some sort of data corruption that prevents MonetDB to start. I get this message: !ERROR: Please move away <log folder> and its corresponding dbfarm. !mvc_init: unable to create system tables. I use Mapi to connect to Monet, but the problem is that in this case I do net get back a failed mapi connection - instead the connection attempt hangs and never returns. Is this a mapi bug? If I remove the log folder Monet goes back up again. I am using v2.28.5 compiled on Windows from CVS (branch May2009). -- View this message in context: http://www.nabble.com/Mapi-connection-hangs-tp23643072p23643072.html Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] Strange io exception
by Alex Bo. 24 May '09

24 May '09

Hi, I am running "Select * from tables" and am going over the results with Mapi commands. I tried to run this query with parallel clients, and reran the query hundreds of times. Once in a while I get this exception: !TypeException:user.s32_7[157]:'io.s3019_1' undefined in: _233:any := io.s3019_1() What does this mean? Why does this happen? I am using v2.28.5 compiled on Windows from CVS (branch May2009). -- View this message in context: http://www.nabble.com/Strange-io-exception-tp23692587p23692587.html Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] pcre exception with LIKE inside CASE
by Alex Bo. 24 May '09

24 May '09

Hi, I can successfully run the following query: select "field1", "field2" from testlike where field2 like '%hel%' However, I cannot run this one: select "field1", "field2", (case when ("field2" like '%hel%') then cast("field1" as double) else cast("field1" as bigint) end) as dd from testlike I get this exception: !MALException:pcre_match:not available as required version of libpcre was not found by configure. (This is on Feb SP2 2009 compiled on Windows from CVS) -- View this message in context: http://www.nabble.com/pcre-exception-with-LIKE-inside-CASE-tp23694479p23694… Sent from the monetdb-users mailing list archive at Nabble.com.

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[MonetDB-users] time series benchmark dataset and query/analyses set
by Tom H 22 May '09

22 May '09

Hi monetDB artistes, I found an epic thread on "Tick Database Implementations" and there were lots of intelligent replies here; Subject:dataset for performance testing a time series implementation http://www.elitetrader.com/vb/showthread.php?s=&threadid=81345&perpage=6&pa… So amongst others, monetdb, kdb+ and HDF5 were mentioned, along with streamSQL and CEP/ESPER style analysis tools. However I think the proof is in the testing, so I was looking for a financial price stream orientated dataset that I could download import and run my analysis against for a metric. (obviously I would only testing performance of running retrieval annd analysis rather than storing the ticks) I had a look at the TPC site, http://www.tpc.org/ but I couldn't find anything relevant. I also found some acedemic papers, with the sort of thing that would be useful, but no datasets supplied. So I would like to suggest maybe taking a dataset like OHLC data for the S&P for the last x years, to get it up to something sizable, and then a bunch of analyses that would test the implementation. Has anyone got any suggestions on such a beast, and indeed would anyone like to compare against my monetDB system with their own HDF5 or kdb implementation? Cheers, T

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[MonetDB-users] ADO .net provider & ODBC error
by Zheng Han 18 May '09

18 May '09

Hi, Is there any ADO .net provider for MonetDB? We tried to use odbc driver in C#. When fecth unicode Chinese values, some error ocurred: System.InvalidOperationException Message="Internal .Net Framework Data Provider error 30." Source="System.Data" StackTrace: at System.Data.ProviderBase.DbBuffer.Validate(Int32 offset, Int32 count) at System.Data.ProviderBase.DbBuffer.PtrToStringUni(Int32 offset, Int32 length) at System.Data.Odbc.OdbcDataReader.internalGetString(Int32 i) at System.Data.Odbc.OdbcDataReader.GetString(Int32 i) at MonetDBTest.Form1.button1_Click(_object_ sender, EventArgs e) in E:\D_Bak\~MyWorks\MonetDB\MonetDBTest\Form1.cs:line 41 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) at System.Windows.Forms.Button.PerformClick() at System.Windows.Forms.Form.ProcessDialogKey(Keys keyData) at System.Windows.Forms.Control.ProcessDialogKey(Keys keyData) at System.Windows.Forms.Control.PreProcessMessage(Message& msg) at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg) at System.Windows.Forms.Application.ThreadContext.PreTranslateMessage(MSG& msg) at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FPreTranslateMessage(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at MonetDBTest.Program.Main() in E:\D_Bak\~MyWorks\MonetDB\MonetDBTest\Program.cs:line 18 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(_object_ state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, _object_ state) at System.Threading.ThreadHelper.ThreadStart() InnerException: Regards, Aiyoyo

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[MonetDB-users] ADO .net provider & ODBC error
by Zheng Han 18 May '09

18 May '09

Hi, Is there any ADO .net provider for MonetDB? We tried to use odbc driver in C#. When fecth unicode Chinese values, some error ocurred: System.InvalidOperationException Message="Internal .Net Framework Data Provider error 30." Source="System.Data" StackTrace: at System.Data.ProviderBase.DbBuffer.Validate(Int32 offset, Int32 count) at System.Data.ProviderBase.DbBuffer.PtrToStringUni(Int32 offset, Int32 length) at System.Data.Odbc.OdbcDataReader.internalGetString(Int32 i) at System.Data.Odbc.OdbcDataReader.GetString(Int32 i) at MonetDBTest.Form1.button1_Click(_object_ sender, EventArgs e) in E:\D_Bak\~MyWorks\MonetDB\MonetDBTest\Form1.cs:line 41 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) at System.Windows.Forms.Button.PerformClick() at System.Windows.Forms.Form.ProcessDialogKey(Keys keyData) at System.Windows.Forms.Control.ProcessDialogKey(Keys keyData) at System.Windows.Forms.Control.PreProcessMessage(Message& msg) at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg) at System.Windows.Forms.Application.ThreadContext.PreTranslateMessage(MSG& msg) at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FPreTranslateMessage(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at MonetDBTest.Program.Main() in E:\D_Bak\~MyWorks\MonetDB\MonetDBTest\Program.cs:line 18 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(_object_ state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, _object_ state) at System.Threading.ThreadHelper.ThreadStart() InnerException: Regards, Zheng Han

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[MonetDB-users] MAL samples
by Henri Asseily 18 May '09

18 May '09

Hi, where can I find some MAL samples? I'm trying to do very simple things such as storing and loading a bat, joining bats and iterating through them. I know I can do an explain on SQL statements, but those seem incredibly convoluted even for a simple select on a single column, which should be a straightforward sql.bind(,,,0) with follow-through sql.resultSet and sql.rsColumn if I understand this whole business correctly. Instead, it's doing a couple of algebra kunion and kdifference that I don't understand. I'm not trying to do MAL algebra on a SQL database, I'm trying to go 100% MAL and hand-coding some simple joins and iterators. I would have gone SQL all the way, but I need to iterate through a bat and calculate a result for each row, then return that sorted new bat based on the result. Doing it in SQL is overly complicated when some simple MAL statements should do the job. Thanks. --- Henri Asseily henri.tel

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