From 8a8da4e6792e19caf3a5995ec5963f37b22d07d8 Mon Sep 17 00:00:00 2001
From: Lucas Francisco Lopez <lucaslopezf@gmail.com>
Date: Wed, 8 Jan 2025 18:23:33 +0100
Subject: [PATCH 1/2] Add HardMaxCacheSize to local cache config

---
 pkg/zcache/config.go | 26 ++++++++++++++++++--------
 pkg/zcache/readme.md | 32 ++++++++++++++++++++++++++++++--
 2 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/pkg/zcache/config.go b/pkg/zcache/config.go
index ba66cf1..81f85c4 100644
--- a/pkg/zcache/config.go
+++ b/pkg/zcache/config.go
@@ -1,13 +1,16 @@
 package zcache
 
 import (
+	"time"
+
 	"github.com/allegro/bigcache/v3"
 	"github.com/go-redis/redis/v8"
 	"github.com/zondax/golem/pkg/logger"
 	"github.com/zondax/golem/pkg/metrics"
-	"time"
 )
 
+const hardMaxCacheSizeDefault = 512
+
 type StatsMetrics struct {
 	Enable         bool
 	UpdateInterval time.Duration
@@ -40,11 +43,12 @@ type RemoteConfig struct {
 }
 
 type LocalConfig struct {
-	Prefix         string
-	Logger         *logger.Logger
-	MetricServer   metrics.TaskMetrics
-	StatsMetrics   StatsMetrics
-	CleanupProcess CleanupProcess
+	Prefix               string
+	Logger               *logger.Logger
+	MetricServer         metrics.TaskMetrics
+	StatsMetrics         StatsMetrics
+	CleanupProcess       CleanupProcess
+	HardMaxCacheSizeInMB int
 }
 
 func (c *RemoteConfig) ToRedisConfig() *redis.Options {
@@ -66,8 +70,14 @@ func (c *RemoteConfig) ToRedisConfig() *redis.Options {
 }
 
 func (c *LocalConfig) ToBigCacheConfig() bigcache.Config {
-	evictionTime := time.Duration(100*365*24) * time.Hour // 100 years
-	return bigcache.DefaultConfig(evictionTime)
+	config := bigcache.DefaultConfig(time.Duration(100*365*24) * time.Hour)
+
+	if c.HardMaxCacheSizeInMB <= 0 {
+		c.HardMaxCacheSizeInMB = hardMaxCacheSizeDefault
+	}
+	config.HardMaxCacheSize = c.HardMaxCacheSizeInMB * 1024 * 1024
+
+	return config
 }
 
 type CombinedConfig struct {
diff --git a/pkg/zcache/readme.md b/pkg/zcache/readme.md
index 86d21c4..4ba7fda 100644
--- a/pkg/zcache/readme.md
+++ b/pkg/zcache/readme.md
@@ -65,10 +65,12 @@ It's important to note that MetricServer is a mandatory configuration field in L
 func main() {
     config := zcache.LocalConfig{
         // CleanupInterval is optional; if omitted, a default value of 12 hours will be used
-        CleanupProcess:  CleanupProcess{
+        CleanupProcess: CleanupProcess{
             Interval: 30 * time.Minute,
         },
-        MetricServer:    metricServer,
+        // HardMaxCacheSizeInMB is optional; if omitted, a default value of 512MB will be used
+        HardMaxCacheSizeInMB: 1024, // Set maximum cache size to 1GB
+        MetricServer: metricServer, 
     }
     
     cache, err := zcache.NewLocalCache(&config)
@@ -182,3 +184,29 @@ func TestSomeFunctionWithMutex(t *testing.T) {
 }
 ```
 
+## Best Practices
+
+### Memory Management
+When using the local cache (BigCache), it's important to understand how memory is managed:
+
+1. **Memory Growth**: BigCache allocates memory in chunks and doesn't immediately release memory when items are deleted or overwritten
+2. **Memory Limit**: The `HardMaxCacheSizeInMB` parameter (default: 512MB) is crucial to prevent unbounded memory growth
+3. **Actual Memory Usage**: The total memory consumption will be slightly higher than `HardMaxCacheSizeInMB` due to:
+   - Shard overhead (approximately 2×(64+32)×n bits per entry)
+   - Internal map structures
+   - Go runtime overhead
+
+
+### Memory Monitoring
+Monitor cache memory usage through the provided metrics:
+- `local_cache_cleanup_item_count`
+- `local_cache_cleanup_deleted_item_count`
+- `local_cache_cleanup_errors`
+- `local_cache_cleanup_last_run`
+
+### Notes
+- BigCache has a known memory leak issue (see [issue #369](https://github.com/allegro/bigcache/issues/369)). To mitigate this:
+  1. Always set `HardMaxCacheSizeInMB` (default: 512MB)
+  2. Monitor memory usage through provided metrics
+  3. Consider using shorter cleanup intervals in high-traffic scenarios
+  4. For critical production environments, consider using the Combined Cache with Redis as primary storage

From d0fcbeb05969dab2e4cfbbc9b98c7ed817efeab6 Mon Sep 17 00:00:00 2001
From: Lucas Francisco Lopez <lucaslopezf@gmail.com>
Date: Wed, 8 Jan 2025 18:24:42 +0100
Subject: [PATCH 2/2] minor change

---
 pkg/zcache/config.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/zcache/config.go b/pkg/zcache/config.go
index 81f85c4..8eb4935 100644
--- a/pkg/zcache/config.go
+++ b/pkg/zcache/config.go
@@ -75,7 +75,7 @@ func (c *LocalConfig) ToBigCacheConfig() bigcache.Config {
 	if c.HardMaxCacheSizeInMB <= 0 {
 		c.HardMaxCacheSizeInMB = hardMaxCacheSizeDefault
 	}
-	config.HardMaxCacheSize = c.HardMaxCacheSizeInMB * 1024 * 1024
+	config.HardMaxCacheSize = c.HardMaxCacheSizeInMB
 
 	return config
 }