[High priority] retentionPeriod loses precision past ~104 days (nanoseconds as JS number)

[jstirnaman]

Summary

retentionPeriod is accepted as a JSON number of nanoseconds across the database tools (create_database, update_database) for all product types. JavaScript numbers are IEEE-754 doubles, so integers are exact only up to Number.MAX_SAFE_INTEGER (2^53 − 1 ≈ 9.007e15). Nanosecond retention values exceed that range at roughly 104 days, so longer retention periods can lose precision.

Details

• 1 day = 86_400 * 1e9 = 8.64e13 ns
• Number.MAX_SAFE_INTEGER / 8.64e13 ≈ 104 days
• Example: 1 year = 3.1536e16 ns ≈ 3.5 × MAX_SAFE_INTEGER — not exactly representable.

Affected (all take retentionPeriod as ns-number):

• src/tools/categories/database.tools.ts — inputSchema/zodSchema type number
• src/services/database-management.service.ts — Cloud Dedicated/Clustered (payload.retentionPeriod), Cloud Serverless (everySeconds from ns), Core/Enterprise (formatRetentionPeriod ns → duration string)

Practical impact: a retention longer than ~104 days may be off by a small amount. For Core/Enterprise specifically, formatRetentionPeriod's hours % 24 === 0 check can fail on an already-imprecise large value and fall back to ${Math.floor(hours)}h, dropping up to an hour.

Suggested fix

Change the retentionPeriod contract to avoid ns-as-number. Options, in rough order of preference:

1. Accept a humantime duration string (e.g. "1y", "90d") — matches the InfluxDB CLI/API and removes the precision problem entirely.
2. Accept seconds instead of nanoseconds (pushes the safe boundary out ~285 years).
3. Accept the ns value as a string and parse server-side.

This is a cross-cutting change to the tool parameter contract for all product types, so it was intentionally left out of #59 (which adds Core/Enterprise retention support).

Context

Found while reviewing #56 / #59. The new unit tests deliberately use periods under the 104-day safe boundary (7d, 60d) to avoid the imprecision.

Priority: high — silent precision loss on a data-retention setting.