If you can predict your cache load in advance, use a custom bigcache.Config to avoid additional memory allocations. This allows fine-grained control over sharding, eviction windows, and memory limits.
import (
"context"
"fmt"
"log"
"time"
"github.com/allegro/bigcache/v3"
)
config := bigcache.Config {
// number of shards (must be a power of 2)
Shards: 1024,
// time after which entry can be evicted
LifeWindow: 10 * time.Minute,
// Interval between removing expired entries (clean up).
// If set to <= 0 then no action is performed.
// Setting to < 1 second is counterproductive — bigcache has a one second resolution.
CleanWindow: 5 * time.Minute,
// rps * lifeWindow, used only in initial memory allocation
MaxEntriesInWindow: 1000 * 10 * 60,
// max entry size in bytes, used only in initial memory allocation
MaxEntrySize: 500,
// prints information about additional memory allocation
Verbose: true,
// cache will not allocate more memory than this limit, value in MB
// if value is reached then the oldest entries can be overridden for the new ones
// 0 value means no size limit
HardMaxCacheSize: 8192,
// callback fired when the oldest entry is removed because of its expiration time or no space left
// for the new entry, or because delete was called. A bitmask representing the reason will be returned.
// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
OnRemove: nil,
// OnRemoveWithReason is a callback fired when the oldest entry is removed because of its expiration time or no space left
// for the new entry, or because delete was called. A constant representing the reason will be passed through.
// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
// Ignored if OnRemove is specified.
OnRemoveWithReason: nil,
}
cache, initErr := bigcache.New(context.Background(), config)
if initErr != nil {
log.Fatal(initErr)
}
cache.Set("my-unique-key", []byte("value"))
if entry, err := cache.Get("my-unique-key"); err == nil {
fmt.Println(string(entry))
}
