Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> Comments on: CQRS – Domain state http://elegantcode.com/2009/12/08/cqrs-domain-state/?utm_source=rss&utm_medium=rss&utm_campaign=cqrs-domain-state Tue, 08 May 2012 09:13:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52361 Roy Mon, 04 Jan 2010 06:42:38 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52361 Nice. Thanks for clearing that up. Nice. Thanks for clearing that up.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-2/#comment-52320 Mark Nijhof Sun, 03 Jan 2010 00:32:04 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52320 <a href="#comment-52273" rel="nofollow">@Roy</a> Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR's so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state. So the creation of these snapshot can be done completely outside the normal process, that's why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well. Hope this helps. @Roy
Ah I see where you are coming from now. The snapshots are only used to speed-up the loading of the AR’s so whenever a AR is requested it will first look in the identity map, if not found it will request it from the event store. The event store will first request an available snapshot and load that into the AR then after that it will load all the events that have occurred after the creation of the snapshot bringing it to the latest state.

So the creation of these snapshot can be done completely outside the normal process, that’s why the deamon. The snapshot are not needed at all, it just speeds up the loading. I am going to spend a post on this topic as well.

Hope this helps.

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52273 Roy Sat, 02 Jan 2010 01:55:33 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52273 I think the word "daemon" in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don't think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client. I think the word “daemon” in the 3rd comment threw me off. To me, that means a background service. I was tring to make sense of why you would run a background service to commit a snapshot of an aggregate. I don’t think I understand the purpose of a snapshot. I was thinking that snapshots are only taken after a commit command is given by the client.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52248 Mark Nijhof Fri, 01 Jan 2010 13:04:26 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52248 <a href="#comment-52247" rel="nofollow">@Roy</a> I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :) @Roy
I am not sure how you got that impression? The identity map determins how long an AR stays in memory, but that is not discussed in this post :)

]]> By: Roy http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-52247 Roy Fri, 01 Jan 2010 12:34:44 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-52247 So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time. So your domain is basically in memory at all times. Meaning, none of your AR are disposed. You constantly add new ones in memory and save the state of those AR from time-to-time.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51252 Mark Nijhof Thu, 10 Dec 2009 11:20:08 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51252 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined. @Aaron Jensen
It looks like Udi is on the same line as you http://www.udidahan.com/2009/12/09/clarified-cqrs/comment-page-1/#comment-36874 saying that some information does not need to be in the domain model at all, independently of the way to build it. Meaning putting much more responsibilities on the reporting side then I imagined.

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51247 Allard Buijze Thu, 10 Dec 2009 07:26:30 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51247 <a href="#comment-51241" rel="nofollow">@Aaron Jensen</a> Aaron, you caught me in a moment of "a snapshot captures full state" thoughts here. I probably didn't get rid of all the "traditional" ways of thinking yet. You've got an absolutely valid point there. Thanks for that! @Aaron Jensen
Aaron, you caught me in a moment of “a snapshot captures full state” thoughts here. I probably didn’t get rid of all the “traditional” ways of thinking yet. You’ve got an absolutely valid point there. Thanks for that!

]]> By: Aaron Jensen http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51241 Aaron Jensen Thu, 10 Dec 2009 02:55:56 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51241 <a href="#comment-51210" rel="nofollow">@Allard Buijze</a> Snapshotting doesn't change the need to persist the state in question in this post. We're simply discussing state that is irrelevant to business logic. You wouldn't need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that's the only place it lives. @Allard Buijze
Snapshotting doesn’t change the need to persist the state in question in this post. We’re simply discussing state that is irrelevant to business logic. You wouldn’t need it ever, so no need to store it in the snapshot. The only place its needed is in reporting, and as such, that’s the only place it lives.

]]> By: Mark Nijhof http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51225 Mark Nijhof Wed, 09 Dec 2009 18:04:41 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51225 <a href="#comment-51222" rel="nofollow">@Allard Buijze</a> Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don't actually need to load all events. (I'll discuss this in more details in the next CQRS post). @Allard Buijze
Yuo are correct the domain generates the snapshot and is the only one that knows the structure. But you can savely delete them as any-time, that just means that now all the events will be loaded again. Now you would probably have a daemon in the background generating snapshots, so hopefully when the AR is needed you don’t actually need to load all events. (I’ll discuss this in more details in the next CQRS post).

]]> By: Allard Buijze http://elegantcode.com/2009/12/08/cqrs-domain-state/comment-page-1/#comment-51222 Allard Buijze Wed, 09 Dec 2009 16:06:51 +0000 http://elegantcode.com/2009/12/08/cqrs-domain-state/#comment-51222 <a href="#comment-51215" rel="nofollow">@Mark Nijhof</a> I am eager to read your next post. I've enjoyed the previous ones, anyway (although your C# code samples use constructs that we don't have in Java ;-) ) My idea was that the "something" that generates the snapshot event would be the domain object itself. In order to do that, it should know what (for example) the last known address was. @Mark Nijhof
I am eager to read your next post. I’ve enjoyed the previous ones, anyway (although your C# code samples use constructs that we don’t have in Java ;-) )

My idea was that the “something” that generates the snapshot event would be the domain object itself. In order to do that, it should know what (for example) the last known address was.

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