Major unimplemented features (as of September 2018) include:

  • backend "soundness" work to ensure corrupt data model states aren't reachable via the API
  • authentication and account creation
  • rate-limiting and spam/abuse mitigation
  • "automated update" bots to consume metadata feeds (as opposed to one-time bulk imports)
  • actual entity creation, editing, deleting through the web interface
  • updating the search index in near-real-time following editgroup merges. In particular, the cache invalidation problem is tricky for some relationships (eg, updating all releases if a container is updated)

Once a reasonable degree of schema and API stability is attained, contributions would be helpful to implement:

  • import (bulk and/or continuous updates) for more metadata sources
  • better handling of work/release distinction in, eg, search results and citation counting
  • de-duplication (via merging) for all entity types
  • matching improvements, eg, for references (citations), contributions (authorship), work grouping, and file/release matching
  • internationalization of the web interface (translation to multiple languages)
  • review of design for accessibility
  • better handling of non-PDF file formats

Longer term projects could include:

  • full-text search over release files
  • bi-directional synchronization with other user-editable catalogs, such as Wikidata
  • better representation of multi-file objects such as websites and datasets
  • alternate/enhanced backend to store full edit history without overloading traditional relational database

Known Issues

Too many right now, but this section will be populated soon.

  • changelog index may have gaps due to postgresql sequence and transaction roll-back behavior

Unresolved Questions

How to handle translations of, eg, titles and author names? To be clear, not translations of works (which are just separate releases), these are more like aliases or "originally known as".

Are bi-directional links a schema anti-pattern? Eg, should "work" point to a "primary release" (which itself points back to the work)?

Should identifier and citation be their own entities, referencing other entities by UUID instead of by revision? Not sure if this would increase or decrease database resource utilization.

Should contributor/author affiliation and contact information be retained? It could be very useful for disambiguation, but we don't want to build a huge database for spammers or "innovative" start-up marketing.

Can general-purpose SQL databases like Postgres or MySQL scale well enough to hold several tables with billions of entity revisions? Right from the start there are hundreds of millions of works and releases, many of which having dozens of citations, many authors, and many identifiers, and then we'll have potentially dozens of edits for each of these, which multiply out to `1e8 * 2e1

  • 2e1 = 4e10`, or 40 billion rows in the citation table. If each row was 32 bytes on average (uncompressed, not including index size), that would be 1.3 TByte on its own, larger than common SSD disks. I do think a transactional SQL datastore is the right answer. In my experience locking and index rebuild times are usually the biggest scaling challenges; the largely-immutable architecture here should mitigate locking. Hopefully few indexes would be needed in the primary database, as user interfaces could rely on secondary read-only search engines for more complex queries and views.

There is a tension between focus and scope creep. If a central database like fatcat doesn't support enough fields and metadata, then it will not be possible to completely import other corpuses, and this becomes "yet another" partial bibliographic database. On the other hand, accepting arbitrary data leads to other problems: sparseness increases (we have more "partial" data), potential for redundancy is high, humans will start editing content that might be bulk-replaced, etc.

There might be a need to support "stub" references between entities. Eg, when adding citations from PDF extraction, the cited works are likely to be ambiguous. Could create "stub" works to be merged/resolved later, or could leave the citation hanging. Same with authors, containers (journals), etc.