objectio: make metadata cache capacity dynamic adjustable

pkg/cnservice/server_query.go

@@ -29,6 +29,7 @@ import (
 	"github.com/matrixorigin/matrixone/pkg/fileservice"
 	"github.com/matrixorigin/matrixone/pkg/lockservice"
 	"github.com/matrixorigin/matrixone/pkg/logutil"
+	"github.com/matrixorigin/matrixone/pkg/objectio"
 	pblock "github.com/matrixorigin/matrixone/pkg/pb/lock"
 	"github.com/matrixorigin/matrixone/pkg/pb/query"
 	"github.com/matrixorigin/matrixone/pkg/pb/status"
@@ -92,6 +93,7 @@ func (s *service) initQueryCommandHandler() {
 	s.queryService.AddHandleFunc(query.CmdMethod_GOMEMLIMIT, s.handleGoMemLimit, false)
 	s.queryService.AddHandleFunc(query.CmdMethod_FileServiceCache, s.handleFileServiceCacheRequest, false)
 	s.queryService.AddHandleFunc(query.CmdMethod_FileServiceCacheEvict, s.handleFileServiceCacheEvictRequest, false)
+	s.queryService.AddHandleFunc(query.CmdMethod_MetadataCache, s.handleMetadataCacheRequest, false)
 }
 
 func (s *service) handleKillConn(ctx context.Context, req *query.Request, resp *query.Response, _ *morpc.Buffer) error {
@@ -572,3 +574,17 @@ func (s *service) handleFileServiceCacheEvictRequest(
 
 	return nil
 }
+
+func (s *service) handleMetadataCacheRequest(
+	ctx context.Context, req *query.Request, resp *query.Response, _ *morpc.Buffer,
+) error {
+
+	// set capacity hint
+	objectio.GlobalCacheCapacityHint.Store(req.MetadataCacheRequest.CacheSize)
+	// evict
+	target := objectio.EvictCache()
+	// response
+	resp.MetadataCacheResponse.CacheCapacity = target
+
+	return nil
+}

pkg/cnservice/server_query_test.go

@@ -1117,3 +1117,18 @@ func Test_service_copy(t *testing.T) {
 	require.Falsef(t, unsafe.Pointer(&srcLock.Rows) == unsafe.Pointer(&got.Rows), "copyTxnInfo Rows should diff. src: %p, got: %p", srcLock.Rows, got.Rows)
 	require.Falsef(t, unsafe.Pointer(&srcLock.Options) == unsafe.Pointer(got.Options), "copyTxnInfo Options should diff. src: %p, got: %p", &srcLock.Options, got.Options)
 }
+
+func Test_service_handleMetadataCacheRequest(t *testing.T) {
+	ctx := context.Background()
+	s := &service{}
+	var resp query.Response
+	err := s.handleMetadataCacheRequest(ctx, &query.Request{
+		MetadataCacheRequest: query.MetadataCacheRequest{
+			CacheSize: 42,
+		},
+	}, &resp, nil)
+	require.Nil(t, err)
+	if resp.MetadataCacheResponse.CacheCapacity != 42 {
+		t.Fatal()
+	}
+}

pkg/objectio/cache.go

@@ -17,6 +17,7 @@ package objectio
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 
 	"github.com/matrixorigin/matrixone/pkg/logutil"
 	"go.uber.org/zap"
@@ -96,16 +97,45 @@ func shardMetaCacheKey(key mataCacheKey) uint64 {
 	return xxhash.Sum64(key[:])
 }
 
+var GlobalCacheCapacityHint atomic.Int64
+
+func cacheCapacityFunc(size int64) fscache.CapacityFunc {
+	return func() int64 {
+		if n := GlobalCacheCapacityHint.Load(); n > 0 {
+			return n
+		}
+		return size
+	}
+}
+
 func init() {
-	metaCache = fifocache.New[mataCacheKey, []byte](fscache.ConstCapacity(metaCacheSize()), shardMetaCacheKey, nil, nil, nil)
+	metaCache = fifocache.New[mataCacheKey, []byte](
+		cacheCapacityFunc(metaCacheSize()),
+		shardMetaCacheKey,
+		nil, nil, nil,
+	)
 }
 
 func InitMetaCache(size int64) {
 	onceInit.Do(func() {
-		metaCache = fifocache.New[mataCacheKey, []byte](fscache.ConstCapacity(size), shardMetaCacheKey, nil, nil, nil)
+		metaCache = fifocache.New[mataCacheKey, []byte](
+			cacheCapacityFunc(size),
+			shardMetaCacheKey,
+			nil, nil, nil,
+		)
 	})
 }
 
+func EvictCache() (target int64) {
+	ch := make(chan int64, 1)
+	metaCache.Evict(ch)
+	target = <-ch
+	logutil.Info("metadata cache forced evicted",
+		zap.Any("target", target),
+	)
+	return
+}
+
 func encodeCacheKey(name ObjectNameShort, cacheKeyType uint16) mataCacheKey {
 	var key mataCacheKey
 	copy(key[:], name[:])