TimesTen and Eclipse java development problem

Question

Hello all
Using TimesTen with JDBC in from a Java code developed on Eclipse I encounter a problem: when running the program in debug mode, everything works fine. Running without debug, or outside Eclipse, results in the following error:
java.sql.SQLException: [TimesTen][TimesTen 7.0.5.0.0 ODBC Driver][TimesTen]TT0837: Cannot attach data store shared-memory segment, error 8 -- file "db.c", lineno 7891, procedure "sbDbCreate"
Does anyone know the cause of this, or can point me to logs or other resources I can look into?
Regards,
Shaul Peled
Nuance Communication Inc.

Answer 1

Okay, it is almost certainly an address space issue. Unfortunately 32-bit Windows is about the most problematic platform from this perspective. A TimesTen datastore is a single, contiguous memory region of size approximating PermSize+TempSize+LogBuffSize+DS header. In your case that will be about 1098 Mb. To 'connect' to this datastore, it is necessary to map the datastore memory (it is a shared mapping allocated from the Windows paging file) into your process (in this case the JVM) as a single region. Unfortunately, unlike most O/S, in Windows shared libraries (DLLs) have to be loaded at fixed locations in the address space defined when the DLL was linked. This means that although your process has a 4 GB address space (with quite a bit reserved for WIndows and other uses) that space is often highly fragmented with various DLLs (system and application) located all over the place. This means that often it is hard to find a single contiguous address space region to map a large datastore.
into.
To verify that this is the issue, could you try reducing the datastore size to say PermSize=128, TempSize=64 and see if you can connect then. If you can then you will have to experiment by slowly increasing Perm and Temp until you find the maximum size store you can accomodate. If you are using no logging (Are you sure that is what you want? You will end up with a single threaded datastore if you do that...) you could reduce LogBuffSize to the smallest allowed value (128 Kb).
If it does turn out to be an address space issue then you have 3 options:
1. Live with a smaller datastore size.
2. Try and re-arrange the memory map by rebasing DLLs to create a larger contiguous region. Note that ijn any event it is very unlikely you will ever be able to exceed ~1.5 Gb for a datastore.
3. Switch to 64-bit Windows, 64-bit TimesTen and a 64-bit JVM. Then the only limit on datastore size is available RAM.
Let me know the outcome.
Regards,
Chris