I was playing around with the TOraAlerter Demo and stumbled across a Busywait Problem for which I have several questions. The situation is basically as follows. An application tries to trigger another one to do a reload. The app does this using the ora-alerter and the reload is done using oraqueries in the OnEvent of the corresponding receiving alerter.
So, one has Apps A & B, where A notifies B, and B does executes several oraqueries in the OnEvent-Handler.
What I have noticed is that it takes quite a bit longer if the reload is executed from within the event than it takes if it is executed later (outside the event). I presume the reason for this is the following code in the TExecThread class:
procedure TExecThread.Execute;
var
hExecThread: IntPtr;
begin
hExecThread := AllocGCHandle(Self, False);
try
try
TRunMethod(FMethodDesc.RunMethod);
FException := nil;
PostMessage(FMethodDesc.hWindow, WM_ENDTHREAD, DWORD(Integer(hExecThread)), 0);
while not Terminated do; <= BUSYWAIT HERE SLOWING APP B DOWN
except .....
The questions I have are:
- Is this done this way by design?
- If so, why?
- Why not put a sleep in there (for instance)?
- Is the TOraAlerter.OnEvent not expected to do "large" updates?
(In which case I'll just change my code.)
Thanks for any insight on this. I am by no means an alerting or threading
expert, so I am thankful for any clues that may enlighten me
)cheerio
christophe