CQL Local Secondary Index is a Scylla-only extension to Cassandra's
secondary index API where the index is separate per partition.
Scylla's documentation guarantees that:
"As of Scylla Open Source 4.0, updates for local secondary indexes are
performed synchronously. When updates are synchronous, the client
acknowledges the write operation only after both the base table
modification and the view up date are written."
This happened automatically with vnodes, because the base table and the
view have the same partition key, so base and view replicas are co-located,
and the view update is always local and therefore done synchronously.
But with tablets, this does NOT happen automatically - the base and view
tablets may be located on different nodes, and the view update may be
remote, and NOT synchronous.
So in this patch we explicitly mark the view as synchronous_update when
building the view for an LSI.
The bigger part of this patch is to add a test which reliably fails
before this patch, and passes after it. The test creates a two-node
cluster and a table with LSI, and pins the base's tablets to one node
and the view's to the second node, forcing the view updates to be
remote. It also uses an injection point to make the view update slower.
The test then writes to the base and immediately tries to use the index
to read. Before this patch, the read doesn't find the new data (contrary
to the guarantee in the documentation). After this patch, the read
does find the new data - because the write waited for the index to
be updated.
Fixes#16371
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
a613a3cad2