joao-r-reis commented on code in PR #1926:
URL:
https://github.com/apache/cassandra-gocql-driver/pull/1926#discussion_r2835395778
##########
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()
Review Comment:
Yeah, the driver can't receive schema events while the control connection is
disconnected so we may lose updates. Refreshing when the control connection
reconnects ensures it is always up to date
##########
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()
Review Comment:
Yeah, the driver can't receive schema events while the control connection is
disconnected so we may lose updates. Refreshing when the control connection
reconnects ensures it is always up to date and we don't miss events
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