lru cache metrics

lbry/conf.py

@@ -638,7 +638,7 @@ class Config(CLIConfig):
         "Strategy to use when selecting UTXOs for a transaction",
         STRATEGIES, "standard")
 
-    transaction_cache_size = Integer("Transaction cache size", 100_000)
+    transaction_cache_size = Integer("Transaction cache size", 2 ** 17)
     save_resolved_claims = Toggle(
         "Save content claims to the database when they are resolved to keep file_list up to date, "
         "only disable this if file_x commands are not needed", True

lbry/stream/downloader.py

@@ -40,7 +40,7 @@ class StreamDownloader:
         async def cached_read_blob(blob_info: 'BlobInfo') -> bytes:
             return await self.read_blob(blob_info, 2)
 
-        if self.blob_manager.decrypted_blob_lru_cache:
+        if self.blob_manager.decrypted_blob_lru_cache is not None:
             cached_read_blob = lru_cache_concurrent(override_lru_cache=self.blob_manager.decrypted_blob_lru_cache)(
                 cached_read_blob
             )

lbry/utils.py

@@ -20,8 +20,11 @@ import pkg_resources
 
 import certifi
 import aiohttp
+from prometheus_client import Counter
+from prometheus_client.registry import REGISTRY
 from lbry.schema.claim import Claim
 
+
 log = logging.getLogger(__name__)
 
 
@@ -206,15 +209,41 @@ async def resolve_host(url: str, port: int, proto: str) -> str:
 class LRUCache:
     __slots__ = [
         'capacity',
-        'cache'
+        'cache',
+        '_track_metrics',
+        'hits',
+        'misses'
     ]
 
-    def __init__(self, capacity):
+    def __init__(self, capacity: int, metric_name: typing.Optional[str] = None):
         self.capacity = capacity
         self.cache = collections.OrderedDict()
+        if metric_name is None:
+            self._track_metrics = False
+            self.hits = self.misses = None
+        else:
+            self._track_metrics = True
+            try:
+                self.hits = Counter(
+                    f"{metric_name}_cache_hit_count", "Number of cache hits", namespace="daemon_cache"
+                )
+                self.misses = Counter(
+                    f"{metric_name}_cache_miss_count", "Number of cache misses", namespace="daemon_cache"
+                )
+            except ValueError as err:
+                log.warning("failed to set up prometheus %s_cache_miss_count metric: %s", metric_name, err)
+                self._track_metrics = False
+                self.hits = self.misses = None
 
-    def get(self, key):
+    def get(self, key, default=None):
-        value = self.cache.pop(key)
+        try:
+            value = self.cache.pop(key)
+            if self._track_metrics:
+                self.hits.inc()
+        except KeyError:
+            if self._track_metrics:
+                self.misses.inc()
+            return default
         self.cache[key] = value
         return value
 
@@ -226,16 +255,43 @@ class LRUCache:
                 self.cache.popitem(last=False)
         self.cache[key] = value
 
+    def clear(self):
+        self.cache.clear()
+
+    def pop(self, key):
+        return self.cache.pop(key)
+
+    def __setitem__(self, key, value):
+        return self.set(key, value)
+
+    def __getitem__(self, item):
+        return self.get(item)
+
     def __contains__(self, item) -> bool:
         return item in self.cache
 
+    def __len__(self):
+        return len(self.cache)
+
+    def __delitem__(self, key):
+        self.cache.pop(key)
+
+    def __del__(self):
+        self.clear()
+        if self._track_metrics:  # needed for tests
+            try:
+                REGISTRY.unregister(self.hits)
+                REGISTRY.unregister(self.misses)
+            except AttributeError:
+                pass
+
 
 def lru_cache_concurrent(cache_size: typing.Optional[int] = None,
                          override_lru_cache: typing.Optional[LRUCache] = None):
     if not cache_size and override_lru_cache is None:
         raise ValueError("invalid cache size")
     concurrent_cache = {}
-    lru_cache = override_lru_cache or LRUCache(cache_size)
+    lru_cache = override_lru_cache if override_lru_cache is not None else LRUCache(cache_size)
 
     def wrapper(async_fn):
 

lbry/wallet/ledger.py

@@ -10,11 +10,11 @@ from collections import defaultdict
 from binascii import hexlify, unhexlify
 from typing import Dict, Tuple, Type, Iterable, List, Optional, DefaultDict, NamedTuple
 
-import pylru
 from lbry.schema.result import Outputs, INVALID, NOT_FOUND
 from lbry.schema.url import URL
 from lbry.crypto.hash import hash160, double_sha256, sha256
 from lbry.crypto.base58 import Base58
+from lbry.utils import LRUCache
 
 from .tasks import TaskGroup
 from .database import Database
@@ -155,7 +155,7 @@ class Ledger(metaclass=LedgerRegistry):
         self._on_ready_controller = StreamController()
         self.on_ready = self._on_ready_controller.stream
 
-        self._tx_cache = pylru.lrucache(self.config.get("tx_cache_size", 1024))
+        self._tx_cache = LRUCache(self.config.get("tx_cache_size", 1024), metric_name='tx')
         self._update_tasks = TaskGroup()
         self._other_tasks = TaskGroup()  # that we dont need to start
         self._utxo_reservation_lock = asyncio.Lock()
@@ -167,7 +167,7 @@ class Ledger(metaclass=LedgerRegistry):
         self._known_addresses_out_of_sync = set()
 
         self.fee_per_name_char = self.config.get('fee_per_name_char', self.default_fee_per_name_char)
-        self._balance_cache = pylru.lrucache(100000)
+        self._balance_cache = LRUCache(2 ** 15)
 
     @classmethod
     def get_id(cls):
@@ -614,8 +614,9 @@ class Ledger(metaclass=LedgerRegistry):
 
         for txid, height in sorted(to_request, key=lambda x: x[1]):
             if cached:
-                if txid in self._tx_cache:
+                cached_tx = self._tx_cache.get(txid)
-                    if self._tx_cache[txid].tx is not None and self._tx_cache[txid].tx.is_verified:
+                if cached_tx is not None:
+                    if cached_tx.tx is not None and cached_tx.tx.is_verified:
                         cache_hits.add(txid)
                         continue
                 else: