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#include "catch.hpp"
#include "duckdb/common/lru_cache.hpp"
#include "duckdb/common/optional_idx.hpp"
#include "duckdb/storage/buffer/buffer_pool.hpp"
#include "duckdb/storage/object_cache.hpp"
#include "duckdb/main/database.hpp"
#include "test_helpers.hpp"
using namespace duckdb; // NOLINT
namespace {
// Test value type
struct TestValue {
int value = 0;
idx_t size = 0;
TestValue(int val, idx_t sz = 100) : value(val), size(sz) {
}
};
} // namespace
TEST_CASE("LRU Cache Basic Operations", "[lru_cache]") {
DuckDB db;
Connection con(db);
auto &context = *con.context;
auto &buffer_pool = DatabaseInstance::GetDatabase(context).GetBufferPool();
SharedLruCache<string, TestValue, BufferPoolPayload> cache(1000);
SECTION("Put and Get") {
auto val1 = make_shared_ptr<TestValue>(42, 100);
auto reservation = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key1", val1, std::move(reservation));
auto result = cache.Get("key1");
REQUIRE(result != nullptr);
REQUIRE(result->value == 42);
REQUIRE(cache.Size() == 1);
REQUIRE(cache.CurrentTotalWeight() == 100);
}
SECTION("Get non-existent key") {
auto result = cache.Get("nonexistent");
REQUIRE(result == nullptr);
}
SECTION("Replace existing key") {
auto val1 = make_shared_ptr<TestValue>(1, 100);
auto val2 = make_shared_ptr<TestValue>(2, 150);
auto reservation1 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key1", val1, std::move(reservation1));
auto reservation2 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/150);
cache.Put("key1", val2, std::move(reservation2));
auto result = cache.Get("key1");
REQUIRE(result != nullptr);
REQUIRE(result->value == 2);
REQUIRE(cache.CurrentTotalWeight() == 150);
}
SECTION("Delete") {
auto val1 = make_shared_ptr<TestValue>(42, 100);
auto reservation = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key1", val1, std::move(reservation));
bool deleted = cache.Delete("key1");
REQUIRE(deleted == true);
REQUIRE(cache.Get("key1") == nullptr);
REQUIRE(cache.Size() == 0);
REQUIRE(cache.CurrentTotalWeight() == 0);
const bool deleted_again = cache.Delete("key1");
REQUIRE(!deleted_again);
}
}
TEST_CASE("LRU Cache Eviction", "[lru_cache]") {
DuckDB db;
Connection con(db);
auto &context = *con.context;
auto &buffer_pool = DatabaseInstance::GetDatabase(context).GetBufferPool();
SECTION("Evict LRU when exceeding max weight") {
SharedLruCache<string, TestValue, BufferPoolPayload> cache(500);
auto val1 = make_shared_ptr<TestValue>(1, 200);
auto val2 = make_shared_ptr<TestValue>(2, 200);
auto val3 = make_shared_ptr<TestValue>(3, 200);
auto reservation1 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/200);
cache.Put("key1", val1, std::move(reservation1));
auto reservation2 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/200);
cache.Put("key2", val2, std::move(reservation2));
auto reservation3 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/200);
cache.Put("key3", val3, std::move(reservation3));
REQUIRE(cache.Get("key1") == nullptr);
REQUIRE(cache.Get("key2") != nullptr);
REQUIRE(cache.Get("key3") != nullptr);
REQUIRE(cache.Size() == 2);
REQUIRE(cache.CurrentTotalWeight() <= 500);
}
SECTION("LRU ordering") {
SharedLruCache<string, TestValue, BufferPoolPayload> cache(300);
auto val1 = make_shared_ptr<TestValue>(1, 100);
auto val2 = make_shared_ptr<TestValue>(2, 100);
auto val3 = make_shared_ptr<TestValue>(3, 100);
auto val4 = make_shared_ptr<TestValue>(4, 100);
auto reservation1 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key1", val1, std::move(reservation1));
auto reservation2 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key2", val2, std::move(reservation2));
auto reservation3 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key3", val3, std::move(reservation3));
cache.Get("key1");
auto reservation4 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key4", val4, std::move(reservation4));
REQUIRE(cache.Get("key1") != nullptr);
REQUIRE(cache.Get("key2") == nullptr);
REQUIRE(cache.Get("key3") != nullptr);
REQUIRE(cache.Get("key4") != nullptr);
}
}
TEST_CASE("LRU Cache Unlimited Memory", "[lru_cache]") {
DuckDB db;
Connection con(db);
auto &context = *con.context;
auto &buffer_pool = DatabaseInstance::GetDatabase(context).GetBufferPool();
SharedLruCache<string, TestValue, BufferPoolPayload> cache(0);
for (int idx = 0; idx < 100; ++idx) {
auto val = make_shared_ptr<TestValue>(idx, 100);
auto reservation = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key" + std::to_string(idx), val, std::move(reservation));
}
REQUIRE(cache.Size() == 100);
}
TEST_CASE("LRU Cache Clear", "[lru_cache]") {
DuckDB db;
Connection con(db);
auto &context = *con.context;
auto &buffer_pool = DatabaseInstance::GetDatabase(context).GetBufferPool();
SharedLruCache<string, TestValue, BufferPoolPayload> cache(1000);
auto val1 = make_shared_ptr<TestValue>(1, 100);
auto val2 = make_shared_ptr<TestValue>(2, 100);
auto reservation1 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key1", val1, std::move(reservation1));
auto reservation2 = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, /*size=*/100);
cache.Put("key2", val2, std::move(reservation2));
cache.Clear();
REQUIRE(cache.Size() == 0);
REQUIRE(cache.CurrentTotalWeight() == 0);
REQUIRE(cache.Get("key1") == nullptr);
REQUIRE(cache.Get("key2") == nullptr);
}
TEST_CASE("LRU Cache Evict To Reduce Memory", "[lru_cache]") {
DuckDB db;
Connection con(db);
auto &context = *con.context;
auto &buffer_pool = DatabaseInstance::GetDatabase(context).GetBufferPool();
// Set max memory to a large value, which exceeds all entries emplaced.
SharedLruCache<string, TestValue, BufferPoolPayload> cache(20000);
// Put a few entries, and check memory consumption.
constexpr idx_t obj_size = 1000;
for (int idx = 0; idx < 10; ++idx) {
auto val = make_shared_ptr<TestValue>(idx, obj_size);
auto reservation = make_uniq<TempBufferPoolReservation>(MemoryTag::OBJECT_CACHE, buffer_pool, obj_size);
cache.Put(StringUtil::Format("key%d", idx), val, std::move(reservation));
}
REQUIRE(cache.Size() == 10);
REQUIRE(cache.CurrentTotalWeight() == 10 * obj_size);
// Perform cache entries eviction, and check memory consumption.
// Evict 4 * objects, leaving 6 objects in cache
const idx_t bytes_to_free = 4 * obj_size;
const idx_t freed = cache.EvictToReduceAtLeast(bytes_to_free);
REQUIRE(freed >= bytes_to_free); // Should free at least the requested amount
REQUIRE(cache.CurrentTotalWeight() == 6 * obj_size);
REQUIRE(cache.Size() == 6);
// The first 4 items should be evicted.
for (int idx = 0; idx < 4; ++idx) {
REQUIRE(cache.Get(StringUtil::Format("key%d", idx)) == nullptr);
}
// The later 6 items should be kept in cache.
for (int idx = 6; idx < 10; ++idx) {
REQUIRE(cache.Get(StringUtil::Format("key%d", idx)) != nullptr);
}
}
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