251db77fcb
This adaptor adapts a mutation reader pausable consumer to the frozen
mutation visitor interface. The pausable consumer protocol allows the
consumer to skip the remaining parts of the partition and resume the
consumption with the next one. To do this, the consumer just has to
return stop_iteration::yes from one of the consume() overloads for
clustering elements, then return stop_iteration::no from
consume_end_of_partition(). Due to a bug in the adaptor, this sequence
leads to terminating the consumption completely -- so any remaining
partitions are also skipped.
This protocol implementation bug has user-visible effects, when the
only user of the adaptor -- read repair -- happens during a query which
has limitations on the amount of content in each partition.
There are two such queries: select distinct ... and select ... with
partition limit. When converting the repaired mutation to to query
result, these queries will trigger the skip sequence in the consumer and
due to the above described bug, will skip the remaining partitions in
the results, omitting these from the final query result.
This patch fixes the protocol bug, the return value of the underlying
consumer's consume_end_of_partition() is now respected.
A unit test is also added which reproduces the problem both with select
distinct ... and select ... per partition limit.
Follow-up work:
* frozen_mutation_consumer_adaptor::on_end_of_partition() calls the
underlying consumer's on_end_of_stream(), so when consuming multiple
frozen mutations, the underlying's on_end_of_stream() is called for
each partition. This is incorrect but benign.
* Improve documentation of mutation_reader::consume_pausable().
Fixes: #20084
Closes scylladb/scylladb#23657
(cherry picked from commit d67202972a)
Closes scylladb/scylladb#23694
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.