[zeromq-dev] 0MQ to the rescue

[Pieter Hintjens]

COBOL on AIX... <eyes glaze over, PTSD kicks in>...

Gonzalo, sounds like a very interesting project.  You'll have seen the
discussion on reliability at
http://www.zeromq.org/blog:requirements-for-reliability?

Regarding the design, you'll probably get more feedback from the list
if you can provide a diagram showing the pieces and how they connect.

-Pieter

On Mon, Aug 9, 2010 at 10:21 PM, gonzalo diethelm <gdiethelm at dcv.cl> wrote:
> I am planning to use 0MQ to create a replication mechanism for a legacy
> system. This oldie is implemented with COBOL programs updating a Sybase
> database (which lives on AIX). Due to its nature, all system context is
> represented in the data stored on Sybase.
>
> I intend to write an extended stored procedure (XSP) in C that will be
> called, via triggers, on each insert, update and delete for certain
> tables on the legacy. When the trigger is invoked, the XSP will push a
> message into a 0MQ socket, containing the table, operation and all
> fields for that row. The receiving end will pull these messages from the
> 0MQ socket, analyze them and figure out what to do in the "next
> generation" implementation of the system.
>
> For the push side, I want to make sure the processing is very light and
> there are no stalls due to waiting for any I/O. My plan is to bind a
> PUSH socket to a well-known address and possibly setting a larger HWM to
> ensure everything stays in memory.
>
> For the receiving side, I want to make sure I don't ever loose any
> messages and don't really care so much if the operations take longer. My
> plan is to connect a PULL socket to the well-known address and using a
> mix of a larger HWM and/or a swap file. I might run several copies of
> this process if necessary (hence the usage of connect here).
>
> Of course I plan on running a few benchmarks of my own to validate my
> assumptions, but I would really love to hear any comments regarding this
> little design. I am very excited because if I can pull this off, I may
> have found a way to integrate legacy and "next generation" in a way that
> will be almost 100% transparent to the legacy and that will allow the
> next generation to move at its own pace.
>
> Thanks in advance and best regards.
>
> --
> Gonzalo Diethelm
>
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