mirror of
https://github.com/scylladb/scylladb.git
synced 2026-05-31 03:56:42 +00:00
2c0b472f44
DynamoDB's *local* secondary index (LSI) allows strongly-consistent reads from the materialized view, which must be able to read what was previously written to the base. To support this, we need the view to use the "synchronous_updates". Previously, with vnodes, there was no need for using this option explicitly, because an LSI has the same partition key as the base table so the base and view replicas are the same, and the local writes are done synchronously. But with tablets, this changes - there is no longer a guarantee that the base and view tablets are located on the same node. So to restore the strong consistency of LSIs when tablets are enabled, this patch explicitly adds the "synchronous_updates" option to views created by Alternator LSIs. We do *not* add this option for GSIs - those do not support strongly-consistent reads. This fix was tested by a test that will be introduced in the following patches. The test showed that before this patch, it was possible that reading with ConsistentRead=True from an LSI right after the base was written would miss the new changes, but after this patch, it always sees the new data in the LSI. Fixes #16313. Signed-off-by: Nadav Har'El <nyh@scylladb.com>