mv: allow skipping view updates when a collection is unmodified
When we generate view updates, we check whether we can skip the
entire view update if all columns selected by the view are unmodified.
However, for collection columns, we only check if they were unset
before and after the update.
In this patch we add a check for the actual collection contents.
We perform this check for both virtual and non-virtual selections.
When the column is only a virtual column in the view, it would be
enough to check the liveness of each collection cell, however for
that we'd need to deserialize the entire collection anyway, which
should be effectively as expensive as comparing all of its bytes.
Fixes: SCYLLADB-996
- (cherry picked from commit 01ddc17ab9)
Parent PR: #28839Closesscylladb/scylladb#28977
* github.com:scylladb/scylladb:
Merge 'mv: allow skipping view updates when a collection is unmodified' from Wojciech Mitros
mv: remove dead code in view_updates::can_skip_view_updates
Closesscylladb/scylladb#29094
6b9aa303d8