Tree Registry

This page is part of the documentation for Orleans.Lattice 9.9.0 (release line 9.9), built 2026-10-04. It is also published as markdown, with every table and list, at README.md, and llms.txt lists every page.

What it shows

Every tree you touch is tracked in a registry. This sample creates three trees (a write auto-registers each), enumerates them with GetAllTreeIdsAsync, probes existence with TreeExistsAsync, and reads each tree's effective per-tree configuration through IOptionsMonitor<LatticeOptions> - including overrides applied with ConfigureLattice(treeName, ...).

Run it

dotnet run --project samples/TreeRegistry

Expected output

Silo starting... ready.

== Creating trees (first write auto-registers each) ==
  wrote to 'orders'
  wrote to 'audit'
  wrote to 'sessions'

== Registered trees (GetAllTreeIdsAsync) ==
  - audit
  - orders
  - sessions

== Existence checks (TreeExistsAsync) ==
  'orders' exists       = True
  'never-written' exists = False

== Per-tree config overrides ==
  orders    CacheTtl=00:00:30   TombstoneGracePeriod=1.00:00:00
  audit     CacheTtl=00:00:00   TombstoneGracePeriod=14.00:00:00
  sessions  CacheTtl=00:00:00   TombstoneGracePeriod=1.00:00:00

Note: 'orders' overrides CacheTtl, 'audit' overrides TombstoneGracePeriod,
      'sessions' shows the global defaults.

When to use

• Operational tooling and dashboards that need to enumerate the live trees in a cluster and show how each one is configured.
• Multi-tenant deployments where different trees want different cache or tombstone policies, set once at startup via ConfigureLattice(treeName, ...).

When not to use

• As a data index. The registry lists tree ids, not keys - use a tag index or a scan to find data within a tree.

Feature docs

docs/lattice/tree-registry.md