TRUNCATE TABLE performs a memtable flush and then discards the sstables of the table being truncated. It collects the highest replay position for both of these. When the highest replay position of the discarded sstables is higher than the highest replay position of the flushed memtable, that means that we have had writes during truncate which have been flushed to disk independently of the truncate process. We check for this and trigger an on_internal_error() which throws an exception, informing the user that writing data concurrently with TRUNCATE TABLE is not advised.
The problem with this is that truncate is also called from DROP KEYSPACE and DROP TABLE. These are raft operations and exceptions thrown by them are caught by the (...) exception handler in the raft applier fiber, which then exits leaving the node without the ability to execute subsequent raft commands.
This commit changes the on_internal_error() into a warning log entry. It also outputs to keyspace/table names, and the offending replay positions which caused the check to fail.
This PR also adds a test which validates that TRUNCATE works correctly with concurrent writes. More specifically, it checks that:
- all data written before TRUNCATE starts is deleted
- none of the data after TRUNCATE completes is deleted
Fixes: #25173Fixes: #25013
Backport is needed in versions which check for truncate with concurrent writes using `on_internal_error()`: 2025.3 2025.2 2025.1
- (cherry picked from commit 268ec72dc9)
- (cherry picked from commit 33488ba943)
Parent PR: #25174Closesscylladb/scylladb#25349
* github.com:scylladb/scylladb:
truncate: add test for truncate with concurrent writes
truncate: change check for write during truncate into a log warning
d845de84aa