Conflict-free replicated data types

Conflict-free replicated data types (CRDTs) support merging values from concurrently modified rows instead of discarding one of the rows as the traditional resolution does.

• CRDTs Overview provides an introduction to CRDTs, including how to use CRDTs in tables, configuration options, and examples of CRDTs.

• Using CRDTs investigates how to use CRDTs in tables, reviews some configuration options, and reviews some examples of CRDTs and how they work.

• Operation-based and state-based CRDTs reviews the differences between operation-based and state-based CRDTs.

• CRDT Disk-space requirements covers disk-size considerations for CRDTs, especially state-based CRDTs.

• CRDTs vs conflict handling/reporting explains how conflict handling and reporting works with CRDTs.

• Resetting CRDT values discusses the challenges of resetting CRDT values and provides some guidance on doing so successfully.

• Implemented CRDTs details each of the 6 available CRDTs available in PGD, with implementation examples.

• CRDTs Overview
  • Introduction to CRDTs
  • CRDTs in PostgreSQL
• Using CRDTs
  • Using CRDTs in tables
    • Non-CRDT example
    • CRDT example
  • Configuration options
  • Different types of CRDTs
  • Query planning and optimization
• Operation-based and state-based CRDTs
  • Operation-based CRDT types (CmCRDT)
  • State-based CRDT types (CvCRDT)
• CRDT Disk-space requirements
  • Operation-based CRDT disk-space reqs
  • State-based CRDT disk-space reqs
• CRDTs vs conflict handling/reporting
  • CRDT types versus conflicts handling
  • CRDT types versus conflict reporting
• Resetting CRDT values
  • Challenges when resetting CRDT values
  • How to reliably handle resetting CRDT values
• Implemented CRDTs
  • Grow-only counter (crdt_gcounter )
  • Grow-only sum (crdt_gsum )
  • Positive-negative counter (crdt_pncounter )
  • Positive-negative sum (crdt_pnsum )
  • Delta counter (crdt_delta_counter )
  • Delta sum (crdt_delta_sum )