---
id: ADR-PFM-ELG-018
title: Decisions and attention items use monthly partitions with thirteen months kept
product_area: platform
module: eligibility
revision: 1
status: proposed
design_intent: confirmed
source_sha:
  services-platform: ad3f6a6582843008ed0f5a17b131878d15829af1
  react-console: baf6dae382d6f41dce976c7f848667ccc37e076f
decision: >-
  Partition decisions and occurrences by UTC month, retain thirteen completed
  months and maintain the current writable month plus two future months.
constrains:
  - DOM-PFM-ELG-003
  - DOM-PFM-ELG-005
  - WF-PFM-ELG-009
origin: >-
  Eligibility Engine architecture D-10 (thirteen months), approved 2026-10-17;
  the partition standard (services-platform docs/partitions.md)
alternatives:
  - option: Delete old records individually
    why_not: Large row deletions create avoidable storage and maintenance costs.
  - option: Retain all history indefinitely
    why_not: >-
      Unlimited retention grows the busiest stores without a recorded product
      need.
consequences:
  - Attention keys hold cross-partition open uniqueness.
  - Sweep cleanup removes orphan supporting rows.
  - >-
    Dropping an open occurrence removes it until a provider republishes the
    condition.
supersedes: []
evidence:
  - >-
    services-platform at ad3f6a6:
    docs/proposals/eligibility/17-decision-register.md;
    docs/milestones/PLAT-M11-eligibility-rules.md (Decisions)
  - >-
    services-platform at ad3f6a6: docs/partitions.md; db/partitioned-tables.ts;
    docs/eligibility.md §4; docs/attention.md §1
---
# Decisions and attention items use monthly partitions with thirteen months kept

## Context

Large history stores need predictable retention and inexpensive removal.

## Decision

Partition decisions and occurrences by UTC month, retain thirteen completed months and maintain the current writable month plus two future months.

## Alternatives Considered

Delete old records individually: Large row deletions create avoidable storage and maintenance costs.

Retain all history indefinitely: Unlimited retention grows the busiest stores without a recorded product need.

## Consequences

Attention keys hold cross-partition open uniqueness. Sweep cleanup removes orphan supporting rows. Dropping an open occurrence removes it until a provider republishes the condition.