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.