Resume an interrupted catalog import from a committed checkpoint
An import loses its process after several committed batches. Restarting from a byte offset inside a quoted multiline record corrupts the next batch.
- Focused work estimate
- 6h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Checkpointing · Idempotency
Estimated field mix
- Data engineering50%
- Database engineering30%
- Distributed systems20%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional wholesaler imports supplier rows into a staging catalog. The current prototype reads the entire file into memory and restarts from zero after a failure. Build the prototype and generated CSV fixture locally before measuring improvements.
Setup prerequisites
- Generate a deterministic 250,000-row synthetic CSV with quoted newlines, invalid records and a stated maximum record size.
- Create a disposable staging database and an import process constrained to 256 MiB; record runtime and available CPU.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- PBATCH-101 · Generate a catalog file that includes difficult CSV boundaries
- PBATCH-102 · Measure peak import memory across parsing, validation and writes
- PBATCH-103 · Attribute import time to parsing, validation and database waits
- PBATCH-104 · Stream records without buffering the rest of the catalog
- PBATCH-105 · Batch staging writes without changing duplicate-SKU behavior
- PBATCH-107 · Report import progress from committed records instead of bytes read
Acceptance criteria
- Bind checkpoints to source digest, parser configuration and import identity.
- Checkpoint only a valid record boundary whose writes are committed, with an explicit idempotency rule for uncertain completion.
- Reject a changed source or configuration and preserve the previous import for inspection.
Implementation constraints
- A raw newline is not a CSV record boundary. State whether resumption seeks to a validated boundary or replays and skips already committed record identities.
Verification to include
- Terminate after commit but before checkpoint acknowledgement, resume and compare the final digest with an uninterrupted import.
- Change one source byte and attempt resumption; no additional staging writes may occur.
Deliverables
- Checkpoint protocol, resume implementation and interruption matrix
Rollout and recovery
Enable resumption only after the failure matrix passes; retain the source and last valid checkpoint when recovery is refused.
Value of the work
For the engineer: Practice streaming, backpressure, allocation analysis and resumable work while retaining exact import semantics.
For the team: Develop a repeatable import performance and recovery exercise that exposes memory, throughput and data-quality tradeoffs.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.