"
When a view's partition key contains only columns from the base's partition
key (and not an additional one), the liveness - existance or disappearance -
of a view-table row is tied to the liveness of the base table row. And
that, in turn, depends not only on selected columns (base-table columns
SELECTed to also appear in the view) but also on unselected columns.
This means that we may need to keep a view row alive even without data,
just because some unselected column is alive in the base table. Before this
patch set we tried to build a single "row marker" in the view column which
tried to summarize the liveness information in all unselected columns.
But this proved unworkable, as explained in issue #3362 and as will be
demonstrated in unit tests at the end of this series.
Because we can't replace several unselected cells by one row marker, what
we do in this series is to add for each for the unselected cells a "virtual
cell" which contains the cell's liveness information (timestamp, deletion,
ttl) but not its value. For collections, we can't represent the entire
collection by one virtual cell, and rather need a collection of virtual
cells.
Fixes#3362
"
* 'virtual-cols-v3' of https://github.com/nyh/scylla:
Materialized Views: test that virtual columns are not visible
Materialized Views: unit test reproducing fixed issue #3362
Materialized Views: no need for elaborate row marker calculations
Materialized Views: add unselected columns as virtual columns
Materialized Views: fill virtual columns
Do not allow selecting a virtual column
schema: persist "view virtual" columns to a separate system table
schema: add "view virtual" flag to schema's column_definition
Add "empty" type name to CQL parser, but only for internal parsing
79d796e710