Seeded intent research program and initial specs

INTENT.md

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+# INTENT.md
+
+## Repository
+
+`doc-store-pg`
+
+## Intent
+
+`doc-store-pg` explores, integrates, and validates a CloudNativePG-native document-store capability built on PostgreSQL.
+
+The project investigates whether the capabilities that make MongoDB attractive as a document database can be provided as a composable PostgreSQL capability without giving up PostgreSQL's relational strengths, operational model, extensibility, and flexible multitenancy boundaries.
+
+The repository is intended to move this question from architectural theory into an inspectable, reproducible implementation and research program.
+
+## Core Hypothesis
+
+Document-oriented storage does not necessarily require a separate database architecture.
+
+A PostgreSQL platform, extended with document-oriented data types, query semantics, indexing, MongoDB-compatible interfaces, and suitable operational tooling, may provide a competitive document-store surface while retaining the advantages of PostgreSQL and CloudNativePG.
+
+`doc-store-pg` exists to test that hypothesis rather than assume it.
+
+## Objectives
+
+The project aims to:
+
+1. Establish a reproducible CloudNativePG-based document-store reference architecture.
+2. Integrate suitable PostgreSQL document-store technologies such as DocumentDB and compatible gateway implementations.
+3. Expose MongoDB-compatible APIs where useful while retaining direct PostgreSQL access.
+4. Measure semantic compatibility with MongoDB rather than treating wire compatibility as sufficient.
+5. Compare document-oriented workloads across native MongoDB and PostgreSQL-based implementations.
+6. Investigate hybrid relational/document workloads that make use of PostgreSQL-specific strengths.
+7. Explore multitenancy models ranging from highly pooled tenants to strongly isolated tenant deployments.
+8. Measure operational characteristics including deployment, failover, backup, restore, upgrade, scaling, observability, and resource efficiency.
+9. Identify which capabilities belong in reusable PostgreSQL extensions, gateway layers, CloudNativePG configuration, Kubernetes control-plane resources, or higher-level orchestration.
+10. Produce evidence that can guide long-term architectural and product decisions.
+
+## Scope
+
+The repository may contain or coordinate work relating to:
+
+- CloudNativePG deployment profiles
+- PostgreSQL extension packaging and lifecycle management
+- DocumentDB integration
+- MongoDB-compatible gateways
+- FerretDB integration where useful
+- BSON and JSONB storage models
+- document query and aggregation semantics
+- indexing strategies
+- MongoDB driver and application compatibility
+- transaction and change-stream behavior
+- PostgreSQL-native access to document data
+- relational/document hybrid queries
+- schema validation
+- observability and query diagnostics
+- benchmark harnesses
+- conformance tests
+- workload generators
+- operational tests
+- multitenancy models
+- tenant placement and isolation policies
+- tenant migration experiments
+- performance and cost analysis
+- architecture research and decision records
+
+## Multitenancy Research
+
+Multitenancy is a first-class concern of the project.
+
+`doc-store-pg` should investigate a continuum of tenant isolation models, including:
+
+### Pooled
+
+Multiple tenants share document structures and storage, with tenant boundaries enforced through mechanisms such as tenant identifiers, PostgreSQL roles, Row-Level Security, gateway policy, and application identity propagation.
+
+### Namespace
+
+Tenants receive distinct PostgreSQL schemas or comparable logical namespaces while sharing a PostgreSQL cluster.
+
+### Database
+
+Tenants receive distinct PostgreSQL databases within a shared CloudNativePG cluster.
+
+### Dedicated
+
+Tenants receive dedicated CloudNativePG / document-store clusters and corresponding compute, storage, security, and failure boundaries.
+
+The project should evaluate whether tenants can move between these models as their requirements evolve without requiring applications to adopt different document APIs.
+
+This creates a central research question:
+
+> Can tenant placement and isolation become configurable properties of the data platform rather than permanent application architecture decisions?
+
+## Compatibility Model
+
+MongoDB compatibility must be treated as a spectrum rather than a binary property.
+
+The project should distinguish at least:
+
+- connection compatibility
+- CRUD compatibility
+- query compatibility
+- index compatibility
+- aggregation compatibility
+- driver compatibility
+- tooling compatibility
+- transaction compatibility
+- change-stream compatibility
+- behavioral and error-semantics compatibility
+- real-application compatibility
+
+Compatibility claims should be backed by reproducible tests.
+
+## Benchmarking Intent
+
+Benchmarking is a core product of the repository rather than an afterthought.
+
+The benchmark program should compare meaningful architectural configurations, potentially including:
+
+- native MongoDB
+- PostgreSQL with JSONB
+- PostgreSQL with document-store extensions
+- PostgreSQL document APIs used directly
+- MongoDB-compatible DocumentDB gateways
+- FerretDB or other compatible gateways
+- different CloudNativePG deployment profiles
+- different multitenancy and isolation models
+
+Benchmarks should measure more than throughput.
+
+Relevant dimensions include:
+
+- latency
+- throughput
+- concurrency
+- storage efficiency
+- index size
+- write amplification
+- CPU efficiency
+- memory efficiency
+- connection overhead
+- noisy-neighbour behavior
+- tenant isolation
+- failover behavior
+- backup and restore
+- recovery objectives
+- upgrade complexity
+- provisioning time
+- tenant migration
+- observability
+- operational complexity
+- cost per workload
+- cost per tenant
+
+Benchmark results should remain reproducible, inspectable, and comparable over time.
+
+## Architectural Principle
+
+The project should prefer composition over reimplementation.
+
+Where mature open-source components already provide BSON handling, MongoDB protocol translation, query semantics, or other document-store functionality, `doc-store-pg` should integrate and evaluate them before implementing replacements.
+
+The repository's durable value should primarily come from:
+
+- architecture
+- integration
+- configuration
+- compatibility profiles
+- operational patterns
+- multitenancy models
+- conformance testing
+- benchmark methodology
+- comparative evidence
+- automation
+- reusable deployment abstractions
+
+rather than unnecessary duplication of upstream database functionality.
+
+## Non-Goals
+
+`doc-store-pg` does not initially aim to:
+
+- implement a MongoDB-compatible database engine from scratch
+- reproduce every MongoDB feature
+- claim drop-in compatibility without evidence
+- replace CloudNativePG
+- create a new PostgreSQL distribution
+- build a distributed sharding system before simpler architectures have been evaluated
+- optimize exclusively for synthetic benchmark scores
+- assume PostgreSQL is superior to MongoDB
+- assume MongoDB compatibility is the only valuable document-store interface
+
+The repository should remain evidence-driven.
+
+## Success Criteria
+
+The project is successful when it can provide clear, reproducible answers to questions such as:
+
+1. Which MongoDB workloads can run unchanged or with minimal adaptation?
+2. What performance overhead is introduced by document abstractions and MongoDB protocol gateways?
+3. Where does native MongoDB retain architectural or operational advantages?
+4. Where does PostgreSQL provide equivalent or better behavior?
+5. Which workloads benefit from combining relational and document models?
+6. How do different multitenancy strategies affect density, isolation, performance, security, and cost?
+7. How effectively can tenants move between pooled and dedicated deployment models?
+8. Which configuration produces the best trade-off for a given workload?
+9. Can a CloudNativePG platform offer document storage without introducing a second independent database operational stack?
+10. Under which conditions should an operator deliberately choose MongoDB instead?
+
+## Expected Repository Outputs
+
+The repository is expected to evolve through artifacts such as:
+
+- `ArchitectureBlueprint.md`
+- `ResearchProgram.md`
+- `BenchmarkSpecification.md`
+- `CompatibilityModel.md`
+- `MultitenancyModel.md`
+- `WorkloadCatalog.md`
+- `BenchmarkResults/`
+- `experiments/`
+- `deploy/`
+- `profiles/`
+- `tests/`
+- `docs/`
+- architecture decision records
+- reproducible benchmark environments
+- machine-readable benchmark results
+
+## Guiding Principle
+
+> Treat document storage as a capability to be composed, measured, and governed — not as a database category to be assumed.
+
+`doc-store-pg` should make the trade-offs between PostgreSQL-based document storage and native document databases visible through working systems and reproducible evidence.