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Subject: [OASIS Issue Tracker] Commented: (MQTT-10) Should Qos=0 retained messages be persisted in the server?
[ http://tools.oasis-open.org/issues/browse/MQTT-10?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=33390#action_33390 ] Raphael Cohen commented on MQTT-10: ----------------------------------- My 2 cents:- I think it depends on what someone means to achieve by doing a server restart. Some scenarios:- - Physical Host in someone's data centre, administrator wants to try to 'fix' a broker configuration issue, so does a restart to flush configuration (eg invoke-rc.d restart x on classic init.d based systems). Probably does want to drop in-memory messages (which might be == QoS 0) - Virtual Host in the cloud, underlying infrastructure needs patching, server stopped and restarted, end user of messaging probably shouldn't know or have to care - Physical or Virtual Host, kernel needs patching, but there's a 5 9s SLA (uggh but true), so a quick restart is needed. So either restart doesn't cause QoS to be lost (as user shouldn't be ware) or it does (to satisfy fast restart goals, so any in-memory QoS aren't flushed to disk first). - 9 to 5 system (a lot of trading systems run only daily), powered off at end of day, probably QoS 0 and everything else can be destroyed. So really, it comes down to what level of g'tee a provider (ie server infrastructure + broker) (either internal datacentre, or virtuals, or cloud) interprets as QoS 0. Perhaps we should offer guidance only / use a MAY (eg, a conforming implementation MAY decide to not retain QoS 0 retained messages over server restarts). > Should Qos=0 retained messages be persisted in the server? > ---------------------------------------------------------- > > Key: MQTT-10 > URL: http://tools.oasis-open.org/issues/browse/MQTT-10 > Project: OASIS Message Queuing Telemetry Transport (MQTT) TC > Issue Type: Improvement > Components: core > Environment: MQTT server > Reporter: Andrew Banks > > The current specification states that : > Retained messages should be kept over restarts of the server. > Is this correct even for Qos=0 retained publications? -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://tools.oasis-open.org/issues/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
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