SYNCORETURN & SYNCPOINT

akodakka · New User Joined: 20 May 2010 Posts: 75 Location: India

Would you please help to understand this commands

My doubt is why we are using SYNCORETURN & SYNCPOINT
if it can be explained with simple example thst will be help ful

Here is what my understanding

PROG A --LINK PROG B (with syncreturn)---

Prog A will pass control to prog B and stop updating any resources
Prog b CAN UPDATE The resources untill it issues a syncpoint

After SYNCPOINT the resources will be available for PROG A

Garry Carroll · Posted: Fri May 28, 2010 2:18 pm

SYNCONRETURN applies to DPL and function-shipping, so your example

akodakka · New User Joined: 20 May 2010 Posts: 75 Location: India

sorry to ask..

What actually you mean by 'COMMIT'

so you are saying if prog A link with Prog B with a SYNCONRETURN

so prog A will start its updates only after a syncpoint or task termination

Garry Carroll · Posted: Fri May 28, 2010 2:48 pm

COMMIT means the finalising of the update process.

A unit-of-work can begin the process of writing updates to, say, a VSAM file but the updates will not appear in the file until the unit-of-work is committed. Until either an explicit or implicit SYNCPOINT occurs, a task failure will result in a roll-back or backout, of the in-flight updates.

ProgA will have started the update process by issuing uncommitted writes to a file. These updates will not be in the VSAM file when ProgB is invoked unless ProgA issues SYNCPOINT before the EXEC CICS LINK(ProgB).

Similarly, ProgB can start updates against, say, another file and these will not be committed to that file until either ProgB issues a SYNCPOINT or ProgB returns to ProgA (which specified SYNCONRETURN).

ProgA can now commit or backout the VSAM updates it had started.

Since both ProgA and ProgB are part of the same task, a failure in ProgB would result in backout of any uncommitted updates that either program had initiated.

If ProgA fails after the SYNCONRETURN from ProgB has completed but before ProgA issues SYNCPOINT, then ProgB's updates are committed but ProgA's updates are rolled-back.

Garry.

akodakka · New User Joined: 20 May 2010 Posts: 75 Location: India

Thanks Garry

So my doubt is what is the need of this commands then

If PROG A ----link B--- then PROG A will wait untill it get the return from PROG B rite?

and in my case

i can see the flow as

prog A---link B (SYNCORETURN)---prog B--link C (SYNCORETRUN)--PROG C -link prog D (syncnreturn)----progD SYSNCPOINT---after D calls MQ

in this case what will be the use of this commands

Garry Carroll · Posted: Fri May 28, 2010 3:17 pm

The manual explains this

akodakka · New User Joined: 20 May 2010 Posts: 75 Location: India

Thanks Garry

So i think these are mainly using for error handling during DPL env
that even if any error happend the updates done can be rolled back

Thanks Garry
Please if you have some more info with this topic...