Having multiple environments open in the same thread.

Question

Dear Sir,
I have a question about the concurrency model inside the bdbje. I read the documents and faqs and wrote some simple
programs using it.
Here is my question, from my understanding, one can open an environment in multiple processes assuming that only
one of the environments is opened for writing. I would like to know how can I open one read environment
and one write environment in the same process. Since in my application, reads and writes can be initiated from
multiple processes [assuming that always having at most one writer]. In my tests when a process receives
a read requests it creates an environment for reading, and if during the reading process the process receives
a write request, it create a new environment to handle the write request. This simple thing throws the following exception:
je.env.isReadOnly is set to false in the config parameter which is incompatible with the value of true in the underlying environment
It seems like I can't have multiple environments with different configurations open at the same time in the same process, i would like
to know if this is really the case, are there any option that I can tweak to fix this.
Thanks,
AliS

Answer 1

hello,
An immutable property of an Environment can not be changed
at runtime. The ReadOnly property for an environment is one of
the few immutable environment properties. Hence, the IllegalArgumentException
was thrown when your application tried to open an environment handle as
ReadWrite when a handle had already been opened ReadOnly. All environment
handles opened by a single process must have the same value for immutable
properties.
You can find some additional information is at:
http://www.oracle.com/technology/documentation/berkeley-db/je/java/index.html
under: EnvironmentConfig
thanks,
Sandra