[Spread-users] How to determine if message sent to a group was delivered to a consumer

John Schultz jschultz at spreadconcepts.com
Wed Feb 2 10:34:51 EST 2011

Spread is an ephemeral messaging system.  The only people that can receive a message are those that are present in the group (in the same partition) when the message is delivered.  Messages are not stored or queued for recipients who come to the group later or are in a different partition.

The only way to know whether or not a message was processed by a receiver is through some form of explicit ACK sent by that receiver.  Spread can give you a weaker guarantee using SAFE delivery.  In particular, if a receiver gets a SAFE message prior to a transitional signal in a membership, then it can know that that message will be delivered to all current members of the membership, unless they crash.


John Lane Schultz
Spread Concepts LLC
Phn: 301 830 8100
Cell: 443 838 2200

On Feb 1, 2011, at 11:13 PM, Bernardinis, Mark wrote:

Hi All,
I am investigating the uses of Spread for a project I am working on and have been successfully able to deliver messages  from the producer to the spread messaging system and retrieve them.
To publish a message to the spread system and find out if any subscribers received it (i.e. it is important that the message is processed).
If I publish a message and there are no subscribers to the group where it was published to, the message is dropped on the floor (or so I believe)… I have confirmed this behaviour by starting a separate instance of my test program and joining the group where the message was delivered to and seeing if any messages existed (there wasn’t any).
I believe this is probably an elementary question and would appreciate any help. My setup is defined as follows;
System Setup
Spread Toolkit 4.1
Spread win32 binary running with the following configuration;
DebugFlags = { PRINT EXIT }
EventLogFile = testlog.out
EventTimeStamp = "[%a %d %b %Y %H:%M:%S]"
DangerousMonitor = false
Spread_Segment {
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