datalake: add compaction_test.py

Adds a new `test_compaction` test, which uses the `KgoVerifierSeqConsumer`
to validate a fully compacted log, along with the `datalake_verifier`
service to validate the Iceberg table.

Also moves the contents of `compaction_gaps_test.py` into
`compaction_test.py`.

tests/rptest/tests/datalake/compaction_gaps_test.py → tests/rptest/tests/datalake/compaction_test.py

@@ -10,16 +10,18 @@
 from time import time
 from rptest.clients.kafka_cat import KafkaCat
 from rptest.clients.types import TopicSpec
-from rptest.services.kgo_verifier_services import KgoVerifierProducer
+from rptest.services.kgo_verifier_services import KgoVerifierProducer, KgoVerifierSeqConsumer
 from rptest.tests.datalake.datalake_services import DatalakeServices
 from rptest.tests.datalake.query_engine_base import QueryEngineType
+from rptest.services.redpanda import MetricsEndpoint
 from rptest.tests.redpanda_test import RedpandaTest
 from rptest.services.redpanda import SISettings
 from rptest.tests.datalake.utils import supported_storage_types
 from ducktape.mark import matrix
 from ducktape.utils.util import wait_until
 from rptest.services.cluster import cluster
 from rptest.utils.mode_checks import skip_debug_mode
+from rptest.tests.datalake.datalake_verifier import DatalakeVerifier
 
 
 class CompactionGapsTest(RedpandaTest):
@@ -118,3 +120,123 @@ def test_translation_no_gaps(self, cloud_storage_type):
                               include_query_engines=[QueryEngineType.TRINO
                                                      ]) as dl:
             self.do_test_no_gaps(dl)
+
+
+class CompactionTest(RedpandaTest):
+    def __init__(self, test_ctx, *args, **kwargs):
+        self.extra_rp_conf = {
+            "iceberg_enabled": "true",
+            "iceberg_catalog_commit_interval_ms": 5000,
+            "datalake_coordinator_snapshot_max_delay_secs": 10,
+            "log_compaction_interval_ms": 2000,
+            "log_segment_size": 2 * 1024**2,  # 2 MiB
+            "compacted_log_segment_size": 1024**2  # 1 MiB
+        }
+
+        super(CompactionTest,
+              self).__init__(test_ctx,
+                             num_brokers=1,
+                             si_settings=SISettings(test_context=test_ctx,
+                                                    fast_uploads=True),
+                             extra_rp_conf=self.extra_rp_conf,
+                             *args,
+                             **kwargs)
+        self.test_ctx = test_ctx
+        self.topic_name = "tapioca"
+        self.msg_size = 1024  # 1 KiB
+        self.total_data = 100 * 1024**2  # 100 MiB
+        self.msg_count = int(self.total_data / self.msg_size)
+        self.kafka_cat = KafkaCat(self.redpanda)
+
+    def setUp(self):
+        # redpanda will be started by DatalakeServices
+        pass
+
+    def produce(self):
+        KgoVerifierProducer.oneshot(self.test_ctx,
+                                    self.redpanda,
+                                    self.topic_name,
+                                    msg_size=self.msg_size,
+                                    msg_count=self.msg_count,
+                                    key_set_cardinality=100,
+                                    validate_latest_values=True,
+                                    clean=True)
+
+    def wait_for_compaction(self):
+        # Restart each redpanda broker to force roll segments
+        self.redpanda.restart_nodes(self.redpanda.nodes)
+
+        def get_complete_sliding_window_rounds():
+            return self.redpanda.metric_sum(
+                metric_name=
+                "vectorized_storage_log_complete_sliding_window_rounds_total",
+                metrics_endpoint=MetricsEndpoint.METRICS,
+                topic=self.topic_name)
+
+        # Sleep until the log has been fully compacted.
+        self.prev_sliding_window_rounds = -1
+
+        def compaction_has_completed():
+            new_sliding_window_rounds = get_complete_sliding_window_rounds()
+            res = self.prev_sliding_window_rounds == new_sliding_window_rounds
+            self.prev_sliding_window_rounds = new_sliding_window_rounds
+            return res
+
+        wait_until(
+            compaction_has_completed,
+            timeout_sec=120,
+            backoff_sec=self.extra_rp_conf['log_compaction_interval_ms'] /
+            1000 * 10,
+            err_msg="Compaction did not stabilize.")
+
+    def verify_log_and_table(self, dl: DatalakeServices):
+        # Verify a fully compacted log with a sequential consumer
+        consumer = KgoVerifierSeqConsumer(
+            self.test_ctx,
+            self.redpanda,
+            self.topic_name,
+            compacted=True,
+            validate_latest_values=True,
+        )
+
+        consumer.start(clean=False)
+        consumer.wait(timeout_sec=120)
+        consumer.free()
+
+        verifier = DatalakeVerifier(self.redpanda,
+                                    self.topic_name,
+                                    dl.trino(),
+                                    compacted=True)
+
+        verifier.start()
+        verifier.wait()
+
+        for partition, offset_consumed in verifier._max_consumed_offsets.items(
+        ):
+            assert consumer.consumer_status.validator.max_offsets_consumed[str(
+                partition)] == offset_consumed
+
+    def do_test_compaction(self, dl: DatalakeServices):
+        dl.create_iceberg_enabled_topic(
+            self.topic_name,
+            iceberg_mode="key_value",
+            config={"cleanup.policy": TopicSpec.CLEANUP_COMPACT})
+
+        for _ in range(5):
+            self.produce()
+            # Compact the data. Compaction settling indicates that
+            # everything will have been translated into the Iceberg table already.
+            self.wait_for_compaction()
+            # Assert on read log and on iceberg table.
+            self.verify_log_and_table(dl)
+
+    @cluster(num_nodes=4)
+    @skip_debug_mode
+    @matrix(cloud_storage_type=supported_storage_types())
+    def test_compaction(self, cloud_storage_type):
+        with DatalakeServices(self.test_ctx,
+                              redpanda=self.redpanda,
+                              filesystem_catalog_mode=False,
+                              include_query_engines=[QueryEngineType.TRINO
+                                                     ]) as dl:
+            self.do_test_compaction(dl)