ADR 0026: Read plans bind resources in execution
Status: Accepted for implementation Date: 2026-09-07 Related: #1136, #1008, ADR 0025
Context
Section titled “Context”Fixed and variable expansion embed paths and ontology mode. Read scans retain
storage providers and nodes(path) retains a hydration directory. DataFusion
54.1 TableScan equality excludes its source, so provider ownership is a binding
problem even when scan equality already ignores location. Expansion and hydrated
expression equality do include their paths.
Options
Section titled “Options”Keeping paths inside opaque handles would preserve the coupling. A global or thread-local resolver would make simultaneous and retained queries ambiguous. Removing schema discovery from lowering would expand this change into #1006.
Decision
Section titled “Decision”Read logical nodes and sources describe the query’s current graph resource and its semantic schema, never a filesystem location or provider address. The current-graph role is deterministic across equivalent plans. Existing checked IDs, relation names, output schemas and composition assumptions remain semantic contracts; they are not substitutes for a pinned execution authority.
An exec-owned SessionConfig extension owns the directory, mode, catalog and existing adjacency/ordinal resources. Physical planning resolves logical scan descriptors and read expressions against that session before executing them. Missing or incompatible bindings fail closed. Physical plans and owned streams retain their bound resources; another session cannot retarget them.
Schema discovery remains in lowering. The mutation family uses the same resource boundary with distinct write admission, as described below. Existing operator names, Arrow schemas, checked-ID encodings and durable formats do not change. No durable plan serialization codec is introduced by this internal resource boundary.
Consequences
Section titled “Consequences”Read plans can be compared and rebound independently of their original project location. The execution boundary must validate semantic assumptions and resolve all read sources, including property and semantic relation providers. Tests must cover relocated complete plans, simultaneous bindings, retained streams, missing authority and incompatible schemas, as well as ordinary query parity and #1094 bounded traversal. The change does not authorize eager graph scans to construct the execution context or a fallback to the working directory.
Mutation family completion (#1008)
Section titled “Mutation family completion (#1008)”CREATE, DELETE, SET and REMOVE use the same deterministic current-graph role. Their logical nodes retain checked identities, expressions, output shape and semantic binding requirements. Paths, ontology mode and executable routing maps belong to an explicit execution-owned write context. Read authority alone does not grant write authority. Missing, read-only or incompatible write bindings fail before any mutation, including literal-only statements.
The existing statement driver remains the owner of ordering, buffered visibility, commit/rollback and write receipts, including MERGE. Physical extension planning and the driver share the admitted session authority; neither recovers a target from a logical node. Runtime ID/name mappings used during lowering are semantic assumptions to validate, rather than an executable provider registry.
All logical extension equality and hashing use their semantic content. Literal and computed property distinctions, composition fingerprints, and output modes remain significant; filesystem placement and execution policy do not. This does not introduce a persisted plan codec or change public Arrow/IR encodings.
Mutation literal keys normalize signed zero and make NaNs reflexive while preserving their payload bits, recursively through lists, maps and spatial coordinates. Computed expressions retain DataFusion’s own equality/hash contract. This policy is local to logical plans; public literal equality and serialization are unchanged. All eleven extension nodes derive equality and hashing, with the shared literal adapter confined to resolved mutation specifications.