Is it 'safe' to restart Apache ODE (Tomcat)?

[Stan Angeloff <st...@angeloff.name>]

Hi,

I have been, for a while, wondering whether it is 'safe' to restart Apache
ODE (Tomcat)? The situation I have in mind is the following: a new process
is deployed which is a complex maze of 'If's, loops, etc. 10, 000 new
instances are created and are left to run for 7 days making it halfway
through the process.

At this point, with 10, 000 active instances and still lots to do, is it
'safe' to gracefully stop the application server and then start it again?
To define safe: all processes will finish any external calls that they are
making, persist any state to the database and restore that state
successfully on next start.

In the past, I've restarted ODE numerous times, but never observed what
happens to on-going external calls. For most cases, the state appears to be
resolved correctly and the engine continues to execute the processes
normally. I have had cases where state is lost, however that's mostly due
to the database becoming saturated with connections and unrelated to the
question at hand.

Any thoughts you may have will be very much appreciated,
Stan

Re: Is it 'safe' to restart Apache ODE (Tomcat)?

[Stan Angeloff <st...@angeloff.name>]

Thank you for taking the time to reply Sathwik, that makes total sense.

On 5 November 2014 09:13, Sathwik B P <sa...@gmail.com> wrote:

> Hi Stan,
>
> ODE maintains the state till the last successful database transaction.
> Transactions are committed when the engine encounters a complex acivity
> such as Receive,Pick, Invoke, Wait etc; After restart of App server, ODE
> engine will pickup and execute from the last committed state.
>
> To your question " all processes will finish any external calls that they
> are making" the answer is NO.
>
> regards,
> sathwik
>
> On Tue, Nov 4, 2014 at 1:36 PM, Stan Angeloff <st...@angeloff.name>
> wrote:
>
> > Hi,
> >
> > I have been, for a while, wondering whether it is 'safe' to restart
> Apache
> > ODE (Tomcat)? The situation I have in mind is the following: a new
> process
> > is deployed which is a complex maze of 'If's, loops, etc. 10, 000 new
> > instances are created and are left to run for 7 days making it halfway
> > through the process.
> >
> > At this point, with 10, 000 active instances and still lots to do, is it
> > 'safe' to gracefully stop the application server and then start it again?
> > To define safe: all processes will finish any external calls that they
> are
> > making, persist any state to the database and restore that state
> > successfully on next start.
> >
> > In the past, I've restarted ODE numerous times, but never observed what
> > happens to on-going external calls. For most cases, the state appears to
> be
> > resolved correctly and the engine continues to execute the processes
> > normally. I have had cases where state is lost, however that's mostly due
> > to the database becoming saturated with connections and unrelated to the
> > question at hand.
> >
> > Any thoughts you may have will be very much appreciated,
> > Stan
> >
>

Re: Is it 'safe' to restart Apache ODE (Tomcat)?

[Sathwik B P <sa...@gmail.com>]

Hi Stan,

ODE maintains the state till the last successful database transaction.
Transactions are committed when the engine encounters a complex acivity
such as Receive,Pick, Invoke, Wait etc; After restart of App server, ODE
engine will pickup and execute from the last committed state.

To your question " all processes will finish any external calls that they
are making" the answer is NO.

regards,
sathwik

On Tue, Nov 4, 2014 at 1:36 PM, Stan Angeloff <st...@angeloff.name>
wrote:

> Hi,
>
> I have been, for a while, wondering whether it is 'safe' to restart Apache
> ODE (Tomcat)? The situation I have in mind is the following: a new process
> is deployed which is a complex maze of 'If's, loops, etc. 10, 000 new
> instances are created and are left to run for 7 days making it halfway
> through the process.
>
> At this point, with 10, 000 active instances and still lots to do, is it
> 'safe' to gracefully stop the application server and then start it again?
> To define safe: all processes will finish any external calls that they are
> making, persist any state to the database and restore that state
> successfully on next start.
>
> In the past, I've restarted ODE numerous times, but never observed what
> happens to on-going external calls. For most cases, the state appears to be
> resolved correctly and the engine continues to execute the processes
> normally. I have had cases where state is lost, however that's mostly due
> to the database becoming saturated with connections and unrelated to the
> question at hand.
>
> Any thoughts you may have will be very much appreciated,
> Stan
>