Add CompactBufferCandidates, used to select buffers to compact.

2 files changed, 100 insertions, 0 deletions

diff --git a/vespalib/src/tests/datastore/compact_buffer_candidates/CMakeLists.txt b/vespalib/src/tests/datastore/compact_buffer_candidates/CMakeLists.txt
new file mode 100644
index 00000000000..d6731071927
--- /dev/null
+++ b/vespalib/src/tests/datastore/compact_buffer_candidates/CMakeLists.txt
@@ -0,0 +1,9 @@
+# Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_executable(vespalib_compact_buffer_candidates_test_app TEST
+    SOURCES
+    compact_buffer_candidates_test.cpp
+    DEPENDS
+    vespalib
+    GTest::GTest
+)
+vespa_add_test(NAME vespalib_compact_buffer_candidates_test_app COMMAND vespalib_compact_buffer_candidates_test_app)
diff --git a/vespalib/src/tests/datastore/compact_buffer_candidates/compact_buffer_candidates_test.cpp b/vespalib/src/tests/datastore/compact_buffer_candidates/compact_buffer_candidates_test.cpp
new file mode 100644
index 00000000000..80c0d571894
--- /dev/null
+++ b/vespalib/src/tests/datastore/compact_buffer_candidates/compact_buffer_candidates_test.cpp
@@ -0,0 +1,91 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/vespalib/datastore/compact_buffer_candidates.h>
+#include <vespa/vespalib/gtest/gtest.h>
+
+using vespalib::datastore::CompactBufferCandidates;
+
+namespace {
+
+constexpr uint32_t num_buffers = 1024;
+constexpr double default_ratio = 0.2 / 2;
+constexpr size_t default_slack = 1000;
+
+};
+
+
+class CompactBufferCandidatesTest : public ::testing::Test
+{
+public:
+    CompactBufferCandidates candidates;
+    CompactBufferCandidatesTest();
+    ~CompactBufferCandidatesTest() override;
+    void reset_candidates(uint32_t max_buffers);
+    CompactBufferCandidatesTest& add(uint32_t buffer_id, size_t used, size_t dead);
+    void assert_select(const std::vector<uint32_t>& exp);
+};
+
+CompactBufferCandidatesTest::CompactBufferCandidatesTest()
+    : ::testing::Test(),
+      candidates(num_buffers, 1, default_ratio, default_slack)
+{
+}
+
+CompactBufferCandidatesTest::~CompactBufferCandidatesTest() = default;
+
+void
+CompactBufferCandidatesTest::reset_candidates(uint32_t max_buffers)
+{
+    candidates = CompactBufferCandidates(num_buffers, max_buffers, default_ratio, default_slack);
+}
+
+CompactBufferCandidatesTest&
+CompactBufferCandidatesTest::add(uint32_t buffer_id, size_t used, size_t dead)
+{
+    candidates.add(buffer_id, used, dead);
+    return *this;
+}
+
+void
+CompactBufferCandidatesTest::assert_select(const std::vector<uint32_t>& exp)
+{
+    std::vector<uint32_t> act;
+    candidates.select(act);
+    EXPECT_EQ(exp, act);
+}
+
+TEST_F(CompactBufferCandidatesTest, select_single)
+{
+    add(0, 10000, 2000).add(1, 10000, 3000);
+    assert_select({1});
+}
+
+TEST_F(CompactBufferCandidatesTest, select_two)
+{
+    reset_candidates(2);
+    add(0, 10000, 2000).add(3, 10000, 3000).add(7, 10000, 4000);
+    assert_select({7, 3});
+}
+
+TEST_F(CompactBufferCandidatesTest, select_all)
+{
+    reset_candidates(4);
+    add(1, 10000, 2000).add(3, 10000, 4000).add(8, 10000, 3000);
+    assert_select({3, 8, 1});
+}
+
+TEST_F(CompactBufferCandidatesTest, select_cutoff_by_ratio)
+{
+    reset_candidates(4);
+    add(1, 100000, 9999).add(3, 100000, 40000).add(8, 100000, 30000);
+    assert_select({3, 8});
+}
+
+TEST_F(CompactBufferCandidatesTest, select_cutoff_by_slack)
+{
+    reset_candidates(4);
+    add(1, 2000, 999).add(3, 2000, 1200).add(9, 2000, 1300);
+    assert_select({9, 3});
+}
+
+GTEST_MAIN_RUN_ALL_TESTS()