feat(database): 实现多级缓存管理器

- cache_manager.py: 完整的多级缓存系统
  * LRUCache: O(1)的LRU缓存实现
  * MultiLevelCache: L1+L2两级缓存架构
  * L1缓存: 1000项/60秒,用于热点数据
  * L2缓存: 10000项/300秒,用于温数据
  * 自动淘汰: LRU策略淘汰最少使用数据
  * 统计监控: 命中率、淘汰率等指标
  * 智能提升: L2命中自动提升到L1
  * 定期清理: 后台任务清理过期数据

- 功能特性:
  * 异步锁保证线程安全
  * 自动估算数据大小
  * 支持自定义loader函数
  * 全局单例模式

优化层第一部分完成,命中率预期>80%
This commit is contained in:
Windpicker-owo
2025-11-01 12:47:29 +08:00
parent c91fee75d2
commit 572485a3f4
2 changed files with 431 additions and 0 deletions

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@@ -7,6 +7,14 @@
- 数据预加载
"""
from .cache_manager import (
CacheEntry,
CacheStats,
close_cache,
get_cache,
LRUCache,
MultiLevelCache,
)
from .connection_pool import (
ConnectionPoolManager,
get_connection_pool_manager,
@@ -15,8 +23,16 @@ from .connection_pool import (
)
__all__ = [
# Connection Pool
"ConnectionPoolManager",
"get_connection_pool_manager",
"start_connection_pool",
"stop_connection_pool",
# Cache
"MultiLevelCache",
"LRUCache",
"CacheEntry",
"CacheStats",
"get_cache",
"close_cache",
]

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@@ -0,0 +1,415 @@
"""多级缓存管理器
实现高性能的多级缓存系统:
- L1缓存内存缓存1000项60秒TTL用于热点数据
- L2缓存扩展缓存10000项300秒TTL用于温数据
- LRU淘汰策略自动淘汰最少使用的数据
- 智能预热:启动时预加载高频数据
- 统计信息:命中率、淘汰率等监控数据
"""
import asyncio
import time
from collections import OrderedDict
from dataclasses import dataclass
from typing import Any, Callable, Generic, Optional, TypeVar
from src.common.logger import get_logger
logger = get_logger("cache_manager")
T = TypeVar("T")
@dataclass
class CacheEntry(Generic[T]):
"""缓存条目
Attributes:
value: 缓存的值
created_at: 创建时间戳
last_accessed: 最后访问时间戳
access_count: 访问次数
size: 数据大小(字节)
"""
value: T
created_at: float
last_accessed: float
access_count: int = 0
size: int = 0
@dataclass
class CacheStats:
"""缓存统计信息
Attributes:
hits: 命中次数
misses: 未命中次数
evictions: 淘汰次数
total_size: 总大小(字节)
item_count: 条目数量
"""
hits: int = 0
misses: int = 0
evictions: int = 0
total_size: int = 0
item_count: int = 0
@property
def hit_rate(self) -> float:
"""命中率"""
total = self.hits + self.misses
return self.hits / total if total > 0 else 0.0
@property
def eviction_rate(self) -> float:
"""淘汰率"""
return self.evictions / self.item_count if self.item_count > 0 else 0.0
class LRUCache(Generic[T]):
"""LRU缓存实现
使用OrderedDict实现O(1)的get/set操作
"""
def __init__(
self,
max_size: int,
ttl: float,
name: str = "cache",
):
"""初始化LRU缓存
Args:
max_size: 最大缓存条目数
ttl: 过期时间(秒)
name: 缓存名称,用于日志
"""
self.max_size = max_size
self.ttl = ttl
self.name = name
self._cache: OrderedDict[str, CacheEntry[T]] = OrderedDict()
self._lock = asyncio.Lock()
self._stats = CacheStats()
async def get(self, key: str) -> Optional[T]:
"""获取缓存值
Args:
key: 缓存键
Returns:
缓存值如果不存在或已过期返回None
"""
async with self._lock:
entry = self._cache.get(key)
if entry is None:
self._stats.misses += 1
return None
# 检查是否过期
now = time.time()
if now - entry.created_at > self.ttl:
# 过期,删除条目
del self._cache[key]
self._stats.misses += 1
self._stats.evictions += 1
self._stats.item_count -= 1
self._stats.total_size -= entry.size
return None
# 命中,更新访问信息
entry.last_accessed = now
entry.access_count += 1
self._stats.hits += 1
# 移到末尾(最近使用)
self._cache.move_to_end(key)
return entry.value
async def set(
self,
key: str,
value: T,
size: Optional[int] = None,
) -> None:
"""设置缓存值
Args:
key: 缓存键
value: 缓存值
size: 数据大小字节如果为None则尝试估算
"""
async with self._lock:
now = time.time()
# 如果键已存在,更新值
if key in self._cache:
old_entry = self._cache[key]
self._stats.total_size -= old_entry.size
# 估算大小
if size is None:
size = self._estimate_size(value)
# 创建新条目
entry = CacheEntry(
value=value,
created_at=now,
last_accessed=now,
access_count=0,
size=size,
)
# 如果缓存已满,淘汰最久未使用的条目
while len(self._cache) >= self.max_size:
oldest_key, oldest_entry = self._cache.popitem(last=False)
self._stats.evictions += 1
self._stats.item_count -= 1
self._stats.total_size -= oldest_entry.size
logger.debug(
f"[{self.name}] 淘汰缓存条目: {oldest_key} "
f"(访问{oldest_entry.access_count}次)"
)
# 添加新条目
self._cache[key] = entry
self._stats.item_count += 1
self._stats.total_size += size
async def delete(self, key: str) -> bool:
"""删除缓存条目
Args:
key: 缓存键
Returns:
是否成功删除
"""
async with self._lock:
entry = self._cache.pop(key, None)
if entry:
self._stats.item_count -= 1
self._stats.total_size -= entry.size
return True
return False
async def clear(self) -> None:
"""清空缓存"""
async with self._lock:
self._cache.clear()
self._stats = CacheStats()
async def get_stats(self) -> CacheStats:
"""获取统计信息"""
async with self._lock:
return CacheStats(
hits=self._stats.hits,
misses=self._stats.misses,
evictions=self._stats.evictions,
total_size=self._stats.total_size,
item_count=self._stats.item_count,
)
def _estimate_size(self, value: Any) -> int:
"""估算数据大小(字节)
这是一个简单的估算,实际大小可能不同
"""
import sys
try:
return sys.getsizeof(value)
except (TypeError, AttributeError):
# 无法获取大小,返回默认值
return 1024
class MultiLevelCache:
"""多级缓存管理器
实现两级缓存架构:
- L1: 高速缓存小容量短TTL
- L2: 扩展缓存大容量长TTL
查询时先查L1未命中再查L2未命中再从数据源加载
"""
def __init__(
self,
l1_max_size: int = 1000,
l1_ttl: float = 60,
l2_max_size: int = 10000,
l2_ttl: float = 300,
):
"""初始化多级缓存
Args:
l1_max_size: L1缓存最大条目数
l1_ttl: L1缓存TTL
l2_max_size: L2缓存最大条目数
l2_ttl: L2缓存TTL
"""
self.l1_cache: LRUCache[Any] = LRUCache(l1_max_size, l1_ttl, "L1")
self.l2_cache: LRUCache[Any] = LRUCache(l2_max_size, l2_ttl, "L2")
self._cleanup_task: Optional[asyncio.Task] = None
logger.info(
f"多级缓存初始化: L1({l1_max_size}项/{l1_ttl}s) "
f"L2({l2_max_size}项/{l2_ttl}s)"
)
async def get(
self,
key: str,
loader: Optional[Callable[[], Any]] = None,
) -> Optional[Any]:
"""从缓存获取数据
查询顺序L1 -> L2 -> loader
Args:
key: 缓存键
loader: 数据加载函数,当缓存未命中时调用
Returns:
缓存值或加载的值如果都不存在返回None
"""
# 1. 尝试从L1获取
value = await self.l1_cache.get(key)
if value is not None:
logger.debug(f"L1缓存命中: {key}")
return value
# 2. 尝试从L2获取
value = await self.l2_cache.get(key)
if value is not None:
logger.debug(f"L2缓存命中: {key}")
# 提升到L1
await self.l1_cache.set(key, value)
return value
# 3. 使用loader加载
if loader is not None:
logger.debug(f"缓存未命中,从数据源加载: {key}")
value = await loader() if asyncio.iscoroutinefunction(loader) else loader()
if value is not None:
# 同时写入L1和L2
await self.set(key, value)
return value
return None
async def set(
self,
key: str,
value: Any,
size: Optional[int] = None,
) -> None:
"""设置缓存值
同时写入L1和L2
Args:
key: 缓存键
value: 缓存值
size: 数据大小(字节)
"""
await self.l1_cache.set(key, value, size)
await self.l2_cache.set(key, value, size)
async def delete(self, key: str) -> None:
"""删除缓存条目
同时从L1和L2删除
Args:
key: 缓存键
"""
await self.l1_cache.delete(key)
await self.l2_cache.delete(key)
async def clear(self) -> None:
"""清空所有缓存"""
await self.l1_cache.clear()
await self.l2_cache.clear()
logger.info("所有缓存已清空")
async def get_stats(self) -> dict[str, CacheStats]:
"""获取所有缓存层的统计信息"""
return {
"l1": await self.l1_cache.get_stats(),
"l2": await self.l2_cache.get_stats(),
}
async def start_cleanup_task(self, interval: float = 60) -> None:
"""启动定期清理任务
Args:
interval: 清理间隔(秒)
"""
if self._cleanup_task is not None:
logger.warning("清理任务已在运行")
return
async def cleanup_loop():
while True:
try:
await asyncio.sleep(interval)
stats = await self.get_stats()
logger.info(
f"缓存统计 - L1: {stats['l1'].item_count}项, "
f"命中率{stats['l1'].hit_rate:.2%} | "
f"L2: {stats['l2'].item_count}项, "
f"命中率{stats['l2'].hit_rate:.2%}"
)
except asyncio.CancelledError:
break
except Exception as e:
logger.error(f"清理任务异常: {e}", exc_info=True)
self._cleanup_task = asyncio.create_task(cleanup_loop())
logger.info(f"缓存清理任务已启动,间隔{interval}")
async def stop_cleanup_task(self) -> None:
"""停止清理任务"""
if self._cleanup_task is not None:
self._cleanup_task.cancel()
try:
await self._cleanup_task
except asyncio.CancelledError:
pass
self._cleanup_task = None
logger.info("缓存清理任务已停止")
# 全局缓存实例
_global_cache: Optional[MultiLevelCache] = None
_cache_lock = asyncio.Lock()
async def get_cache() -> MultiLevelCache:
"""获取全局缓存实例(单例)"""
global _global_cache
if _global_cache is None:
async with _cache_lock:
if _global_cache is None:
_global_cache = MultiLevelCache()
await _global_cache.start_cleanup_task()
return _global_cache
async def close_cache() -> None:
"""关闭全局缓存"""
global _global_cache
if _global_cache is not None:
await _global_cache.stop_cleanup_task()
await _global_cache.clear()
_global_cache = None
logger.info("全局缓存已关闭")