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Ferenc

>No other application or thread accesses the same db. (I assume more
>threads should not be a problem).

OK - that's good. It means we don't have to look at that class of problem at
least. Multiple threads shouldn't be a problem as all access to the journal
file happens through a synchronized Journal object.

>I thought about the workaround that you mention ((transLevel=0), but I
>guess it would not be a safe solution.

You're right, it would be safe if the import preceded an application run.
However, if the import is an irregular activity you could take the system
down, import the data with transLevel=0, and then start up again with
transaction re-enabled. However if you import a lot then this would be
pretty inconvenient.

>It is strange that the file is deleted sometimes after inserting few
>hundred other times after tens of thousands of rows.

I wonder if maybe there's some delay between a request for a file to be
deleted and the actual delete taking place on NT? I'll mail you a separate
version of Journal.class that does this. Let's see if it has any effect.
(BTW - I can't get this bug to happen here, but if anyone else out there is
have problems with imports on NT then I'd like to hear about it).

Regards

Peter Hearty
Lutris Technologies UK Ltd.
-----Original Message-----
From: Ferenc Csizmadia <fcsiz@chemaxon.com>
To: instantDB@enhydra.org <instantDB@enhydra.org>
Date: 12 July 2000 12:50
Subject: Re: InstantDB: FileNotFoundException: idb.jrl


>Re: InstantDB: FileNotFoundException: idb.jrl
>
>Peter,
>
>No other application or thread accesses the same db. (I assume more
>threads should not be a problem).
>I thought about the workaround that you mention ((transLevel=0), but I
>guess it would not be a safe solution.
>
>Environment.
>OS: NT4 (SP6)
>Java: Sun JDK 1.3
>
>It is strange that the file is deleted sometimes after inserting few
>hundred other times after tens of thousands of rows.
>
>Regards,
>Ferenc
>
>PS:
>-We have a Java development tool for chemistry (http://www.jchem.com)
>that stores and accesses chemical data through JDBC. I am testing IDB
>because we would like to suggest it (as one of several possible
>choices) for our users. If everything works out fine we would include
>IDB in our demo system (if this is legal).
>- Please CC the answer to my address, because I am not a member of the
>list.
>
>> InstantDB periodically tries to truncate the journal file back to zero
>> length. It sounds like something is going wrong in the process. AFAIK,
>> there's no way to do an explicit truncation of a RandomAccessFile in Java
>> (anyone out there care to educate me though?), so InstantDB does a file
>> delete followed by a create to truncate the log.
>>
>> There are several possibilities.
>>
>> First, can we rule out any possibility of you running two programs on the
>> same database at once (just asking to make sure)?
>>
>> Once that's ruled out, could you let me know if your application has
>> multiple threads accessing the database at the same time?
>>
>> As a work around you could always set transaction logging off during the
>> import (transLevel=0 in the .prp file). However I would like to get as
much
>> detail on this as possible. In particular, which OS and JVM (with
versions)
>> that are being used.
>>
>> Regards
>>
>> Peter Hearty
>> Lutris Technologies UK Ltd.
>> -----Original Message-----
>> From: Ferenc Csizmadia
>> To: instantDB@enhydra.org
>> Date: 10 July 2000 11:09
>> Subject: InstantDB: FileNotFoundException: idb.jrl
>>
>>
>> >Hi,
>> >
>> >I would like to import rows into an InstantDB database through JDBC
>> >using INSERT.
>> >After INSERT-ing a couple of hundreds or thousands (this seems random)
>> >of records the system removes the idb.jrl file and I get
>> >FileNotFoundException.
>> >
>> >I tried using the InstantDB driver both directly and through RmiJdbc,
>> >but there is no difference (it seems the exception comes sooner when
>> >RmiJdbc is applied).
>> >
>> >Transaction handlings is not applied explicitly.
>> >
>> >When I try to debug by recording trace information, the problem
>> >disappeares (but the system slows down).
>> >
>> >The same program code works when other database engines (MySQL,
>> >Oracle, MS SQL Server ....) are used.
>> >
>> >This is the exception:
>> >java.sql.SQLException: Problem opening/creating journal file: idb.jrl
>> >java.io.FileNotFoundException: C:\htdocs\jchem\idb\system\idb.jrl
>> >(Access is denied)
>> >        at
>>
>sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemote
>> Call.java:245)
>> >
>> >        at
>>
>sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:220)
>> >
>> >        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:354)
>> >        at
>>
>RmiJdbc.RJPreparedStatementServer_Stub.executeUpdate(RJPreparedStatementSer
ver_Stub.java:272)
>>
>
>
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