7d551f99be
The memtable wants to listen for changes in its `total_memory` in order to decrease its `_flushed_memory` in case some of the freed memory has already been accounted as flushed. (This can happen because the flush reader sees and accounts even outdated MVCC versions, which can be deleted and freed during the flush). Today, the memtable doesn't listen to those changes directly. Instead, some calls which can affect `total_memory` (in particular, the mutation cleaner) manually check the value of `total_memory` before and after they run, and they pass the difference to the memtable. But that's not good enough, because `total_memory` can also change outside of those manually-checked calls -- for example, during LSA compaction, which can occur anytime. This makes memtable's accounting inaccurate and can lead to unexpected states. But we already have an interface for listening to `total_memory` changes actively, and `dirty_memory_manager`, which also needs to know it, does just that. So what happens e.g. when `mutation_cleaner` runs is that `mutation_cleaner` checks the value of `total_memory` before it runs, then it runs, causing several changes to `total_memory` which are picked up by `dirty_memory_manager`, then `mutation_cleaner` checks the end value of `total_memory` and passes the difference to `memtable`, which corrects whatever was observed by `dirty_memory_manager`. To allow memtable to modify its `_flushed_memory` correctly, we need to make `memtable` itself a `region_listener`. Also, instead of the situation where `dirty_memory_manager` receives `total_memory` change notifications from `logalloc` directly, and `memtable` fixes the manager's state later, we want to only the memtable listen for the notifications, and pass them already modified accordingl to the manager, so there is no intermediate wrong states. This patch moves the `region_listener` callbacks from the `dirty_memory_manager` to the `memtable`. It's not intended to be a functional change, just a source code refactoring. The next patch will be a functional change enabled by this.
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cqlpy - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.