In-memory only DB

Updated.
Hi,
I just started to write some test programs to test BDB C APIs. I have a questions:
How do I create a DB entirely in shared memory? I tried this:
env_flags = DB_CREATE | DB_INIT_MPOOL | DB_SYSTEM_MEM;
I got the following error:
BDB1546 unable to join the enviroment
Environment open failed: Resource temporarily unavailable
Thanks
Han
Edited by: 902412 on Dec 14, 2011 4:45 PM
Edited by: 902412 on Dec 14, 2011 4:48 PM

Emily Fu, Oracle Berkeley DB wrote:
Hi,
Do you mean to create BDB environment in shared memory, or database file, or log? There are different Berkeley DB files that could be created in memory. You might refer to http://docs.oracle.com/cd/E17076_02/html/articles/inmemory/C/index.html.
My main purpose is to have the database file in shared memory because I am looking for: a) best possible performance. and b) persistent data across process restarts. It is ok to lose data after system reboot. What will be the best approach to do a) and b) ?
>
As the system memory is architecture-dependent, could you please let us know what platform you are running on? To use shared memory region, you might refer to http://docs.oracle.com/cd/E17076_02/html/programmer_reference/env_region.html and http://docs.oracle.com/cd/E17076_02/html/api_reference/C/envopen.html.
I am running Ubuntu Linux on Intel Xeon CPU platform.
thanks
Han
>
Emily Fu
Oracle Berkeley DB

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