raj-ummadisetty commented on code in PR #1926:
URL:
https://github.com/apache/cassandra-gocql-driver/pull/1926#discussion_r2829796089
##########
metadata.go:
##########
@@ -243,51 +245,66 @@ const (
// queries the cluster for schema information for a specific keyspace
type schemaDescriber struct {
- session *Session
- mu sync.Mutex
+ session *Session
+ mu sync.Mutex
+ schemaRefresher *refreshDebouncer
+ schemaMeta atomic.Value // *schemaMeta
+}
- cache map[string]*KeyspaceMetadata
+type schemaMeta struct {
+ keyspaceMeta map[string]*KeyspaceMetadata
}
// creates a session bound schema describer which will query and cache
// keyspace metadata
func newSchemaDescriber(session *Session) *schemaDescriber {
- return &schemaDescriber{
+ meta := new(schemaMeta)
+ describer := &schemaDescriber{
session: session,
- cache: map[string]*KeyspaceMetadata{},
}
+ describer.schemaMeta.Store(meta)
+ return describer
+}
+
+func (s *schemaDescriber) getSchemaMetaForRead() *schemaMeta {
+ meta, _ := s.schemaMeta.Load().(*schemaMeta)
+ return meta
+}
+
+func (s *schemaDescriber) getSchemaMetaForUpdate() *schemaMeta {
+ meta := s.getSchemaMetaForRead()
+ metaNew := new(schemaMeta)
+ if meta != nil {
+ *metaNew = *meta
+ }
+ return metaNew
}
// returns the cached KeyspaceMetadata held by the describer for the named
// keyspace.
func (s *schemaDescriber) getSchema(keyspaceName string) (*KeyspaceMetadata,
error) {
- s.mu.Lock()
- defer s.mu.Unlock()
-
- metadata, found := s.cache[keyspaceName]
+ metadata, found := s.getSchemaMetaForRead().keyspaceMeta[keyspaceName]
if !found {
- // refresh the cache for this keyspace
- err := s.refreshSchema(keyspaceName)
+ // refresh the cache
+ err := s.refreshSchemaMetadata()
if err != nil {
return nil, err
}
-
- metadata = s.cache[keyspaceName]
+ metadata, found =
s.getSchemaMetaForRead().keyspaceMeta[keyspaceName]
+ if !found {
+ return nil, ErrKeyspaceDoesNotExist
+ }
}
return metadata, nil
}
-// clears the already cached keyspace metadata
-func (s *schemaDescriber) clearSchema(keyspaceName string) {
- s.mu.Lock()
- defer s.mu.Unlock()
-
- delete(s.cache, keyspaceName)
-}
-
// forcibly updates the current KeyspaceMetadata held by the schema describer
// for a given named keyspace.
+//
+// Deprecated: Schema refreshes should be triggered through the schemaRefresher
+// refreshDebouncer (debounceRefreshSchemaMetadata) which batches and debounces
+// refresh requests for all keyspaces via refreshSchemas.
func (s *schemaDescriber) refreshSchema(keyspaceName string) error {
Review Comment:
As discussed in the thread, we will need it for `KeyspaceMetadata(keyspace
string)` when caching is disabled.
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