[SOLR-725] CoreContainer/CoreDescriptor/SolrCore cleansing

• Type: Improvement
• Status: Reopened
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.3
• Assignee: Unassigned
• Reporter: Henri Biestro
• Created: 25/Aug/08 08:56
• Updated: 30/Nov/13 14:12

Description

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.

CoreDescriptor: describes the parameters of a SolrCore

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

Operations

The class is only a parameter passing facility

SolrCore: manages a Lucene index

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

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

CoreContainer: manages all relations between cores & descriptors

Definitions

• has a set of aliases (each of them pointing to one core)
  • ensure alias uniqueness.

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

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
• rename: renames a core

CoreAdminHandler: handles CoreContainer operations

• load/create: CoreContainer load
• unload: CoreContainer unload
• reload: CoreContainer reload
• swap: CoreContainer swap
• alias: CoreContainer alias
• unalias: CoreContainer unalias
• rename: CoreContainer rename
• persist: CoreContainer persist, writes the solr.xml
• stauts: returns the status of all/one SolrCore

Issue Links

• relates to: SOLR-723 SolrCore & aliasing/swapping may lead to confusing JMX
• relates to: SOLR-735 CoreContainer.unload should remove all aliases of a core
• relates to: SOLR-722 CoreContainer.reload should make core aliases point to reloaded core
• relates to: SOLR-731 CoreDescriptor.getCoreContainer should not be public
• relates to: SOLR-724 CoreDescriptor.{get,set}CoreProperties should probably not be public (but package private)