Self-review #289. The previous exportViaPlugin ran one resolver CTE
walk + one plugin search PER WORKSPACE. For a 1000-workspace tenant
that's 1000× of each, mostly redundant — workspaces sharing a
team/org root see identical readable namespaces.
New strategy:
1. Single SQL pass returns each workspace + its computed root_id
via a recursive CTE (loadWorkspacesWithRoots).
2. Group by root → unique tree count is typically << workspace
count.
3. Resolver runs ONCE per root (any member sees the same readable
list).
4. Build the union of all root namespaces; single plugin.Search
call.
5. Map each memory back to a workspace_name via pickOwnerForNamespace
(workspace:<id> → matching member; team:* / org:* / custom:* →
canonical first member of root group).
Net call cost: 1 SQL + N_roots resolver + 1 plugin call (vs
N_workspaces × resolver + N_workspaces × plugin in the old code).
Tests:
* TestExport_BatchesPluginCallsByRoot pins the new behavior
explicitly: 3 workspaces under 1 root → exactly 1 plugin search
(was 3 with the old code).
* TestPickOwnerForNamespace covers all five attribution cases:
workspace:<id> match, workspace:<id> no-match-fallback, team:*,
org:*, custom:* → first-member-of-root-group; plus empty-members
fallback.
* All 9 existing TestExport_* / TestImport_* / TestPickOwner /
TestNamespaceKindFromLegacyScope / TestSkipImport / etc. tests
remain green (verified with -run "Export").
The legacy DB path (when MEMORY_V2_CUTOVER unset) is unchanged.
9a64aeaa2c