> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kinetica.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Memory-Only Tables

*Memory-only tables* are not persisted by default like a regular
[table](/content/concepts/tables). You can add, modify, or delete records in a
*memory-only table*.

A *memory-only table* name must adhere to the standard
[naming criteria](/content/concepts/tables#table-naming-criteria). Each *memory-only table*
exists within a [schema](/content/concepts/schemas) and follows the standard
[name resolution rules](/content/concepts/tables#table-name-resolution) for persisted
*tables*.

The following scenarios/endpoints will create a *memory-only table* (unless
persistence is specified):

* Using the [/aggregate/groupby](/content/api/rest/aggregate_groupby_rest),
  [/aggregate/unique](/content/api/rest/aggregate_unique_rest), or
  [/aggregate/unpivot](/content/api/rest/aggregate_unpivot_rest) endpoints with the `result_table`
  option specified
* [Projection](/content/concepts/projections) -- created from
  [/create/projection](/content/api/rest/create_projection_rest)
* [Union](/content/concepts/unions) (also includes [intersect](/content/concepts/intersect) and
  [except](/content/concepts/except) operations) -- created from
  [/create/union](/content/api/rest/create_union_rest)
* Creating a [table](/content/concepts/tables) using [/create/table](/content/api/rest/create_table_rest)
  with the `is_result_table` option set to `true`

## Considerations

* Ingestion speed is better than persisted tables, as there are no disk writes.
* There's no reliance on lookups between connected *join* data sets or scanning
  mask on *filtered* data sets, resulting in faster queries.
* All *memory-only tables* created by endpoints copy data from their source data
  sets, thus their memory footprint can be quite large compared to a
  [join view](/content/concepts/joins) or a
  [filtered view](/content/concepts/filtered_views).

## Limitations and Cautions

* [Primary Key](/content/concepts/tables#primary-key) fields contained within *memory-only tables*
  cannot be [updated](/content/api/rest/update_records_rest).
* Object ID cannot be used to [update](/content/api/rest/update_records_rest)
  or [delete](/content/api/rest/delete_records_rest) records.
  This means updating or deleting records in a *memory-only table* is not possible through
  the [GAdmin Data UI](/content/admin/gadmin/data).
* A *memory-only table* is not persisted, by default, and will not survive a
  database restart, though each endpoint that creates a *memory-only table* has
  an option to persist the *table* instead.
* *Memory-only tables* can be evicted to disk cache if RAM is limited, thus
  incurring disk writes
* Individual *memory-only table* types have additional limitations and
  properties that may differ from the preceding limitations. More information
  can be found in [Aggregation](/content/concepts/aggregation), [Except](/content/concepts/except), [Intersect](/content/concepts/intersect),
  [Projections](/content/concepts/projections), and [Union](/content/concepts/unions).