Collections whose name starts with _ are reserved. Some are virtual (computed on read from the engine’s live
state), some are stored and written only by ogd. All are read with the full language; writes to them are
refused or limited to their own operations.
Collection Content
_memoryOne global row (profile, limits, current and peak bytes, pressure state, RSS, spill and external-group counters) and one row per memory class _query_memoryQuery admission: a global row and one row per running operation _memory_eventsRecent memory reservations and releases (a bounded ring) _index_observationsPer query shape: fingerprint, access path, executions, scanned, returned, elapsed and average µs
on _memory | where scope == "global" | select profile, current_bytes, peak_bytes, pressure_state
on _query_memory | where scope != "global"
on _index_observations | where collection == "orders" | sort executions desc | limit 10
Collection Content Written by
_viewsEvery version of every view (chapter 11 ) define view, undefine view_cacheOne entry per materialized view and scope (chapter 12 ) og-core _cache.v<key>s<slot>The rows of a materialized view in a scope og-core _values.v<hash>The rows of a literal values […] source og-core, once
Collection Content
_appsInstalled Apps and their definitions _placesPlaces _identities, _devicesIdentities and their devices _permissionsAccess grants _pools, _policiesCommercial pools and policies (policy enrollment mode) _event_outboxDurable events waiting for delivery
These are managed by ogd operations and protected by authorization; a Place reads only what concerns it.
Field Written on Meaning
_placeEvery row written in a Place The Place _app_instanceEvery row written by an App instance The App instance
A request in a Place reads only rows carrying its _place (and _app_instance when it names one). Do not write
these fields yourself: the Core stamps them.