cache: handle default arguments for both cache types

Signed-off-by: Vicent Marti <vmg@strn.cat>
vitessio · Feb 4, 2021 · a3feeb8 · a3feeb8
1 parent 9fe7cc0
commit a3feeb8
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Showing 3 changed files with 28 additions and 15 deletions.
diff --git a/go/cache/cache.go b/go/cache/cache.go
@@ -29,6 +29,31 @@ package cache
 // a LRU cache).
 const DefaultCacheSize = SizeInEntries(5000)
 
+// GuessCapacity returns a Capacity value for a cache instance based on the defaults in Vitess
+// and the options passed by the user
+func GuessCapacity(inEntries, inBytes int64) Capacity {
+	switch {
+	// If the default cache has a byte capacity, only override it if the user has explicitly
+	// passed a capacity in entries
+	case DefaultCacheSize.Bytes() != 0:
+		if inEntries != 0 {
+			return SizeInEntries(inEntries)
+		}
+		return SizeInBytes(inBytes)
+
+	// If the default cache has capacity in entries, only override it if the user has explicitly
+	// passed a capacity in bytes
+	case DefaultCacheSize.Entries() != 0:
+		if inBytes != 0 {
+			return SizeInBytes(inBytes)
+		}
+		return SizeInEntries(inEntries)
+
+	default:
+		panic("DefaultCacheSize is not initialized")
+	}
+}
+
 // const DefaultCacheSize = SizeInBytes(64 * 1024 * 1024)
 
 // Cache is a generic interface type for a data structure that keeps recently used

diff --git a/go/vt/vtgate/vtgate.go b/go/vt/vtgate/vtgate.go
@@ -179,11 +179,7 @@ func Init(ctx context.Context, serv srvtopo.Server, cell string, tabletTypesToWa
 	srvResolver := srvtopo.NewResolver(serv, gw, cell)
 	resolver := NewResolver(srvResolver, serv, cell, sc)
 	vsm := newVStreamManager(srvResolver, serv, cell)
-
-	var cacheSize cache.Capacity = cache.SizeInEntries(*queryPlanCacheSize)
-	if *lfuQueryPlanCacheSizeBytes != 0 {
-		cacheSize = cache.SizeInBytes(*lfuQueryPlanCacheSizeBytes)
-	}
+	cacheSize := cache.GuessCapacity(*queryPlanCacheSize, *lfuQueryPlanCacheSizeBytes)
 
 	rpcVTGate = &VTGate{
 		executor: NewExecutor(ctx, serv, cell, resolver, *normalizeQueries, *streamBufferSize, cacheSize),
@@ -503,11 +499,7 @@ func LegacyInit(ctx context.Context, hc discovery.LegacyHealthCheck, serv srvtop
 	srvResolver := srvtopo.NewResolver(serv, gw, cell)
 	resolver := NewResolver(srvResolver, serv, cell, sc)
 	vsm := newVStreamManager(srvResolver, serv, cell)
-
-	var cacheSize cache.Capacity = cache.SizeInEntries(*queryPlanCacheSize)
-	if *lfuQueryPlanCacheSizeBytes != 0 {
-		cacheSize = cache.SizeInBytes(*lfuQueryPlanCacheSizeBytes)
-	}
+	cacheSize := cache.GuessCapacity(*queryPlanCacheSize, *lfuQueryPlanCacheSizeBytes)
 
 	rpcVTGate = &VTGate{
 		executor: NewExecutor(ctx, serv, cell, resolver, *normalizeQueries, *streamBufferSize, cacheSize),

diff --git a/go/vt/vttablet/tabletserver/query_engine.go b/go/vt/vttablet/tabletserver/query_engine.go
@@ -165,11 +165,7 @@ type QueryEngine struct {
 // You must call this only once.
 func NewQueryEngine(env tabletenv.Env, se *schema.Engine) *QueryEngine {
 	config := env.Config()
-
-	var cacheSize cache.Capacity = cache.SizeInEntries(config.QueryCacheSize)
-	if config.LFUQueryCacheSizeBytes != 0 {
-		cacheSize = cache.SizeInBytes(config.LFUQueryCacheSizeBytes)
-	}
+	cacheSize := cache.GuessCapacity(int64(config.QueryCacheSize), config.LFUQueryCacheSizeBytes)
 
 	qe := &QueryEngine{
 		env:              env,