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scylladb/compaction
Lakshmi Narayanan Sreethar 69c385f540 compaction: make drain wait for compactions to stop during shutdown
During shutdown, the compaction_manager starts stopping ongoing
compaction tasks through `really_do_stop()` method as soon as it
receives a signal from the abort source. Later, when the database object
shuts down, it calls `compaction_manager::drain` to ensure that all
compaction tasks have stopped. However, `compaction_manager::drain` is
currently implemented in such a way that, during shutdown, it
effectively becomes a no-op because the compaction_manager has already
initiated the stopping of tasks. As a result the caller assumes that all
the compaction tasks have stopped and proceeds to close all the tables.
This can lead to race conditions where table closures overlap with
compaction tasks that are still running, resulting in exceptions like :

```
exception during mutation write to 127.0.0.1:
utils::internal::nested_exception<std::runtime_error> (Could not write
mutation system:compaction_history
(pk{0010b70d31705e0411efb2edf6467f094c8b}) to commitlog):
seastar::gate_closed_exception (gate closed)
```

This commit fixes the issue by updating `compaction_manager::drain` to
invoke `stop_ongoing_compactions` even during shutdown to ensure that it
waits for the ongoing compaction tasks to complete. The
`stop_ongoing_compactions` method will also send a stop request to these
tasks before waiting, but the request will be ignored by the tasks as
they would have already received one earlier from `really_do_stop()`.

Fixes #20197

Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>

Closes scylladb/scylladb#20715
2024-10-09 12:08:32 +03:00
..