Memory-Only Tables
Memory-only tables are not persisted by default like a regular
table. You can add, modify, or delete records in a
memory-only table.
The following scenarios/endpoints will create a memory-only table (unless
persistence is specified):
Limitations and Cautions
- Primary Key fields contained within memory-only tables
cannot be updated.
- Object ID cannot be used to update
or delete records -- this means
updating or deleting records in a memory-only table is not possible through
the GAdmin Data UI.
- Memory-only tables cannot contain store-only or
non-charN string column types.
- 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.
- Individual memory-only table types have additional limitations and
properties that may differ from the preceding limitations. More information
can be found in Aggregation, Except, Intersect,
Projections, and Union.
Memory Implications
All memory-only table types listed above copy data from their source data
sets, thus their memory footprint can be quite large compared to a
join view or a filtered view. However,
because the data is copied, there's no reliance on lookups between connected
join data sets or scanning mask on filtered data sets, resulting in faster
queries.