ClosePostmasterPorts(false);

MyBgworkerEntry= (BackgroundWorker*)

MemoryContextAlloc(TopMemoryContext,sizeof(BackgroundWorker));

memcpy(MyBgworkerEntry,&rw->rw_worker,sizeof(BackgroundWorker));

MemoryContextSwitchTo(TopMemoryContext);

MemoryContextDelete(PostmasterContext);

PostmasterContext=NULL;

MyBgworkerEntry=&rw->rw_worker;

StartBackgroundWorker();

break;

default:

rw->rw_pid=worker_pid;

rw->rw_backend->pid=rw->rw_pid;

ReportBackgroundWorkerPID(rw);

break;

}

}

PostmasterContext --- this is the postmaster's normal working context.

After a backend is spawned, it can delete PostmasterContext to free its

copy of memory the postmaster was using that it doesn't need.

(Anything that has to be passed from postmaster to backends is passed

in TopMemoryContext. The postmaster has only TopMemoryContext,

PostmasterContext, and ErrorContext --- the remaining top-level contexts

are set up in each backend during startup.)

Note that in non-EXEC_BACKEND builds, the postmaster's copy of pg_hba.conf

and pg_ident.conf data is used directly during authentication in backend

processes; so backends can't delete PostmasterContext until that's done.

(The postmaster has only TopMemoryContext, PostmasterContext, and

ErrorContext --- the remaining top-level contexts are set up in each

backend during startup.)

CacheMemoryContext --- permanent storage for relcache, catcache, and

related modules. This will never be reset or deleted, either, so it's