AFAIU writing/reading to/from a shared DB is very convenient when you use the registry. We do not need to maintain separate database scripts, etc and worry about migration. In case of a complex data structure like the topology, the DB schema can be changing rapidly and a nightmare to maintain.
If I understand correctly, the problem we have here is storing the data in the binary format. Registry provides couple of methods to store them in non-binary format, either using RXT or simple name-value pairs. The advantage I see in a database is the ability to query and retrieve information. If there is a proper way to handle this in registry, maybe by using associations/dependencies [1] (We need to check with a registry expert), IMHO using registry for persisting this data would be very convenient than using a database. [1]. https://docs.wso2.org/display/Governance460/Managing+Relationships+of+a+Resource On Fri, Jun 20, 2014 at 10:37 AM, Imesh Gunaratne <im...@apache.org> wrote: > +1 for direct database approach. > > Few points: > - Registry store resource content as blobs even though the content format > is text. > - Therefore as Udara has pointed out we will need to write a registry > client to do the migrations if we go with the registry. > - If we use a set of databases (SM, AS, CC), we will be able to provide > database scripts for migrations. > - Which I think the most convenient way to migrate data. > - However with this approach we will need to use transactions when writing > to the database to make sure it works fine in a distributed environment (if > SM, AS, CC are clustered). > > WDYT? > > > On Thu, Jun 19, 2014 at 8:03 PM, Isuru Haththotuwa <isu...@apache.org> > wrote: > >> >> >> >> On Thu, Jun 19, 2014 at 12:35 PM, Nirmal Fernando <nirmal070...@gmail.com >> > wrote: >> >>> I think we should go for databases. >>> >> Else, a non binary method supported in registry, such as rxt or simple >> name-value pairs. >> >>> >>> >>> On Thu, Jun 19, 2014 at 12:26 PM, Udara Liyanage <ud...@wso2.com> wrote: >>> >>>> Hi Chris, >>>> >>>> In json also if there is a it will assign the default value for non >>>> existing variables when converting from json to java object structure. >>>> Still if there is a considerable change in object structure, we have to >>>> perform additional work in migration. >>>> >>>> Say we have introduced an variable x, which links to y in another class >>>> so on, then we have to do additional work, otherwise it is in a >>>> inconsistent state. >>>> >>>> >>>> On Thu, Jun 19, 2014 at 12:20 PM, chris snow <chsnow...@gmail.com> >>>> wrote: >>>> >>>>> Hi Udara, I'm not sure of the situation with JSON, but when using XML >>>>> it is possible to evolve a schema as long as changes are done in a >>>>> backward compatible way. For example, if you add an optional field, >>>>> the parsing code will be able to read xml created with and without the >>>>> field. However, IIRC java object serialisation is much more rigid and >>>>> this won't work. >>>>> >>>>> On Thu, Jun 19, 2014 at 6:45 AM, Udara Liyanage <ud...@wso2.com> >>>>> wrote: >>>>> > Hi Imesh/Dinesh, >>>>> > >>>>> > Though we used a readable json/xml/text still we can't migrate >>>>> seamlessly? >>>>> > When migrating we have to read the old json and convert it it the >>>>> new object >>>>> > structure. >>>>> > Could you please explain how making it readable helps to migrate >>>>> seamlessly. >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > On Wed, Jun 18, 2014 at 2:19 PM, Imesh Gunaratne <im...@apache.org> >>>>> wrote: >>>>> >> >>>>> >> Hi Dinesh, >>>>> >> >>>>> >> Great! Please provide your thoughts on the changes required in >>>>> registry >>>>> >> persistence logic as you progress. >>>>> >> >>>>> >> Thanks >>>>> >> >>>>> >> >>>>> >> On Wed, Jun 18, 2014 at 12:27 PM, Dinesh Bandara <dine...@wso2.com> >>>>> wrote: >>>>> >>> >>>>> >>> Hi, >>>>> >>> >>>>> >>> When I started work on [1] and I thought to persist cartridge >>>>> >>> configuration in JSON format in Stratos Manager's registry and >>>>> observed the >>>>> >>> above behavior which does not provide the readability of existing >>>>> artifacts. >>>>> >>> Will work on [2] >>>>> >>> >>>>> >>> [1] https://issues.apache.org/jira/browse/STRATOS-568 >>>>> >>> [2] https://issues.apache.org/jira/browse/STRATOS-664 >>>>> >>> >>>>> >>> Thanks >>>>> >>> >>>>> >>> >>>>> >>> On Wed, Jun 4, 2014 at 10:18 AM, Imesh Gunaratne <im...@apache.org >>>>> > >>>>> >>> wrote: >>>>> >>>> >>>>> >>>> Hi All, >>>>> >>>> >>>>> >>>> In Stratos 4.0.0 Stratos Manager, Cloud Controller and Autoscaler >>>>> store >>>>> >>>> their artifacts in registry in binary format (Java objects are >>>>> serialized >>>>> >>>> and stored). This might cause problems when migrating an existing >>>>> Stratos >>>>> >>>> deployment to a newer version with changes in above artifacts. >>>>> >>>> >>>>> >>>> Therefore it would be better if we could change this format to >>>>> JSON or >>>>> >>>> something similar which could be easily read and updated if the >>>>> definitions >>>>> >>>> of the artifacts change in a newer Stratos version. >>>>> >>>> >>>>> >>>> More importantly we might need to create tasks in JIRA to prepare >>>>> >>>> migration scripts if we do any modifications to the above >>>>> artifacts once >>>>> >>>> 4.0.0 release is done. >>>>> >>>> >>>>> >>>> https://issues.apache.org/jira/browse/STRATOS-664 >>>>> >>>> >>>>> >>>> Thanks >>>>> >>>> >>>>> >>>> >>>>> >>>> -- >>>>> >>>> Imesh Gunaratne >>>>> >>>> >>>>> >>>> Technical Lead, WSO2 >>>>> >>>> Committer & PPMC Member, Apache Stratos >>>>> >>> >>>>> >>> >>>>> >>> >>>>> >>> >>>>> >>> -- >>>>> >>> Dinesh Bandara >>>>> >>> Software Engineer >>>>> >>> WSO2 Inc.; http://wso2.com >>>>> >>> lean.enterprise.middleware >>>>> >>> >>>>> >> >>>>> >> >>>>> >> >>>>> >> -- >>>>> >> Imesh Gunaratne >>>>> >> >>>>> >> Technical Lead, WSO2 >>>>> >> Committer & PPMC Member, Apache Stratos >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > -- >>>>> > >>>>> > Udara Liyanage >>>>> > Software Engineer >>>>> > WSO2, Inc.: http://wso2.com >>>>> > lean. enterprise. middleware >>>>> > >>>>> > web: http://udaraliyanage.wordpress.com >>>>> > phone: +94 71 443 6897 >>>>> >>>>> >>>>> >>>>> -- >>>>> Check out my professional profile and connect with me on LinkedIn. >>>>> http://lnkd.in/cw5k69 >>>>> >>>> >>>> >>>> >>>> -- >>>> >>>> Udara Liyanage >>>> Software Engineer >>>> WSO2, Inc.: http://wso2.com >>>> lean. enterprise. middleware >>>> >>>> web: http://udaraliyanage.wordpress.com >>>> phone: +94 71 443 6897 >>>> >>> >>> >>> >>> -- >>> Best Regards, >>> Nirmal >>> >>> Nirmal Fernando. >>> PPMC Member & Committer of Apache Stratos, >>> Senior Software Engineer, WSO2 Inc. >>> >>> Blog: http://nirmalfdo.blogspot.com/ >>> >> >> > > > -- > Imesh Gunaratne > > Technical Lead, WSO2 > Committer & PPMC Member, Apache Stratos >
