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Handling stale messages
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Nicolas Huyghe
Hi there,
When looking at source code, I see two ways of notifying subscription staleness: mamaStatus: MAMA_MSG_STATUS_STALE and mamaQuality: MAMA_QUALITY_STALE
What is the difference between the two and should both be handled?
Thanks
-Nicolas |
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Glenn McClements <gmcclements@...>
Hi Nicolas,
The main difference is that MAMA_QUALITY_STALE is a property of a mamaSubscription object, while MAMA_MSG_STATUS_STALE is
a property of the mamaMsg object - you will receive stale messages whenever a gap is detected, and the subscription will be stale at that point also. The best way to detect whether a particular topic is stale however is to implement the relevant subscription
callbacks and you will be automatically notified.
Generally you do not have to do anything to recover from stale subscriptions, as OpenMAMA will attempt to recover automatically, though you may have application specific code that you wish to invoke e.g. some warning propagated to the user. Also note that
the concept of a gap and staleness is only for "market data" subscriptions, not "basic" subscriptions.
The OpenMAMA Developer's Guide, p67-70, gives a good overview of the data quality state machine.
Glenn
From: Nicolas Huyghe <Nicolas.Huyghe@...>
Date: Fri, 14 Sep 2012 05:49:31 -0500 To: "openmama-users@..." <openmama-users@...> Subject: [Openmama-users] Handling stale messages Hi there,
When looking at source code, I see two ways of notifying subscription staleness: mamaStatus: MAMA_MSG_STATUS_STALE and mamaQuality: MAMA_QUALITY_STALE
What is the difference between the two and should both be handled?
Thanks
-Nicolas Please consider the environment before printing this e-mail. This e-mail may contain confidential and/or privileged information. If you are not the intended recipient or have received this e-mail in error, please advise the sender immediately by reply e-mail and delete this message and any attachments without retaining a copy. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden. |
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