Collection version history » History » Revision 11

Revision 10 (Peter Amstutz, 09/05/2018 03:51 PM) → Revision 11/17 (Tom Morris, 09/06/2018 01:50 PM)

h1. Collection version history 


 Background: desired API features (#13494, #13561) epic ticket is #13109 
 * Get current + previous versions of a collection with a single API call 
 * Search all current + previous versions of collections with a single API call 
 * Stable small numeric "version number" for each version of a given collection 

 h2. Design 

 * Store all versions in the collection table (much easier to do paging) 
 * New database column "current_version_uuid" for latest version this the same as "uuid" 
 * New database column indicates user-friendly version number (starting at 1) -- can be assigned safely after locking "current" row for update 
 * Assign version number to the current version -- this way {uuid,version} can be used as a permanent reference to a specific version 
 * Flag "include_past_versions" for "list" API to include old versions (otherwise, filter on current_version_uuid=uuid -- might need to adjust indexes to maintain performance) 
 * Flag in site configuration to enable preserving old versions in database 
 * Update owner_uuid of all old versions (in a transaction) when it changes in the current version 
 * A permission link to the current version only implies permission to the most recent version (not the history) 
 * Prohibit permission links to old versions (should be handled by check "can only make links to things that are visible to you", which should not include old versions) 
 * Old versions may not be modified except for certain fields which must be synchronized with "current" version changes (owner_uuid, trash_at, delete_at).    Updating owner_uuid, trash_at, delete_at does not update modified_at so modified_at shows when the version was created 
 * Old versions with duplicate "name" does not conflict with (owner_uuid, name) uniqueness constraint 
 * The following changes introduce a new version: manifest_text (portable_data_hash), description, properties, name,  
 * The following changes do not introduce a new version, and a copied to all past version records: replication_*, storage_classes_*, trash_at/delete_at/is_trashed, owner_uuid, uuid (update current_uuid to retain database consistency) 

 New proposal: 
 * Add a checkpoint_at field to the record which suspends creation of new versions on updates until the given datetime. This checkpoint_at can be updated and moved forward incrementally if desired. 
 * Alternative: have this be a system-wide config parameter 
 * Have an API ability to explicitly create versions when desired