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https://issues.apache.org/jira/browse/SOLR-725?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12626216#action_12626216
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Yonik Seeley commented on SOLR-725:
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bq. In reality, why would anyone want to alias to an existing name.
It's like a rename, but doesn't remove the source.
bq. We actually delete an existing one and rename to that.
That's not atomic... requests that come inbetween can fail.
Rename should be able to overwrite an existing entry (that's independent from
the alias issue).
bq. Just imagine I register a JMX object w/ a name and suddenly it is not more
available with that name.
Isn't that the desired behavior with rename or swap?
> CoreContainer/CoreDescriptor/SolrCore cleansing
> -----------------------------------------------
>
> Key: SOLR-725
> URL: https://issues.apache.org/jira/browse/SOLR-725
> Project: Solr
> Issue Type: Improvement
> Affects Versions: 1.3
> Reporter: Henri Biestro
> Attachments: solr-725.patch
>
>
> These 3 classes and the name vs alias handling are somewhat confusing.
> The recent SOLR-647 & SOLR-716 have created a bit of a flux.
> This issue attemps to clarify the model and the list of operations.
> h3. CoreDescriptor: describes the parameters of a SolrCore
> h4. Definitions
> * has one name
> ** The CoreDescriptor name may represent multiple aliases; in that
> case, first alias is the SolrCore name
> * has one instance directory location
> * has one config & schema name
> h4. Operations
> The class is only a parameter passing facility
> h3. SolrCore: manages a Lucene index
> h4. Definitions
> * has one unique *name* (in the CoreContainer)
> ** the *name* is used in JMX to identify the core
> * has one current set of *aliases*
> ** the name is the first alias
> h4. Name & alias operations
> * *get name/aliases*: obvious
> * *alias*: adds an alias to this SolrCore
> * *unalias*: removes an alias from this SolrCore
> * *name*: sets the SolrCore name
> ** potentially impacts JMX registration
> * *rename*: picks a new name from the SolrCore aliases
> ** triggered when alias name is already in use
> h3. CoreContainer: manages all relations between cores & descriptors
> h4. Definitions
> * has a set of aliases (each of them pointing to one core)
> ** ensure alias uniqueness.
> h4. SolrCore instance operations
> * *load*: makes a SolrCore available for requests
> ** creates a SolrCore
> ** registers all SolrCore aliases in the aliases set
> ** (load = create + register)
> * *unload*: removes a core idenitified by one of its aliases
> ** stops handling the Lucene index
> ** all SolrCore aliases are removed
> * *reload*: recreate the core identified by one of its aliases
> * *create*: create a core from a CoreDescriptor
> ** readies up the Lucene index
> * *register*: registers all aliases of a SolrCore
>
> h4. SolrCore alias operations
> * *swap*: swaps 2 aliases
> ** method: swap
> * *alias*: creates 1 alias for a core, potentially unaliasing a
> previously used alias
> ** The SolrCore name being an alias, this operation might trigger
> a SolrCore rename
> * *unalias*: removes 1 alias for a core
> ** The SolrCore name being an alias, this operation might trigger
> a SolrCore rename
>
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