/**
* Confidence decay migration
*
* Adds columns to memories table for per-memory decay configuration:
* - decay_rate: Per-memory rate multiplier (NULL = global, 0 = pinned)
* - last_refreshed_at: Decay anchor timestamp (NULL = use created_at)
* - confidence_floor: Minimum effective confidence (NULL = global)
* - decay_function: Override: exponential, linear, step, none
*/
import type { Migration, MigrationDatabase } from "./types";
export const migration011ConfidenceDecay: Migration = {
version: "011",
name: "confidence_decay",
destructive: false,
up(db: MigrationDatabase): void {
// Add decay_rate column - per-memory rate multiplier
// NULL = use global config, 0 = pinned (no decay)
db.exec(`
ALTER TABLE memories ADD COLUMN decay_rate REAL DEFAULT NULL
`);
// Add last_refreshed_at column - decay anchor timestamp
// NULL = use created_at as anchor
db.exec(`
ALTER TABLE memories ADD COLUMN last_refreshed_at INTEGER DEFAULT NULL
`);
// Add confidence_floor column - minimum effective confidence
// NULL = use global floor from config
db.exec(`
ALTER TABLE memories ADD COLUMN confidence_floor REAL DEFAULT NULL
`);
// Add decay_function column - override the decay function type
// NULL = use global config, values: 'exponential', 'linear', 'step', 'none'
db.exec(`
ALTER TABLE memories ADD COLUMN decay_function TEXT DEFAULT NULL
`);
// Create single index on last_refreshed_at for "find stale memories" queries
// Intentionally not a composite index as per plan to avoid premature optimization
db.exec(`
CREATE INDEX IF NOT EXISTS idx_memories_last_refreshed
ON memories(last_refreshed_at)
`);
},
down(db: MigrationDatabase): void {
// Drop the index
db.exec("DROP INDEX IF EXISTS idx_memories_last_refreshed");
// Note: SQLite < 3.35 can't DROP COLUMN; columns remain but are ignored
// For SQLite 3.35+, you could use:
// ALTER TABLE memories DROP COLUMN decay_rate;
// ALTER TABLE memories DROP COLUMN last_refreshed_at;
// ALTER TABLE memories DROP COLUMN confidence_floor;
// ALTER TABLE memories DROP COLUMN decay_function;
// But for compatibility, we leave columns in place - they will be ignored
},
};
