Don't forward requests for well-known schemas to connector

This requires hard-coding knowledge about sys and information_schema in
MetadataManager. It's a hack until we figure out how we want to model
these going forward.

presto-main/src/main/java/com/facebook/presto/metadata/MetadataManager.java

@@ -72,6 +72,9 @@
 public class MetadataManager
  implements Metadata
 {
+ private static final String SYS_SCHEMA_NAME = "sys";
+ private static final String INFORMATION_SCHEMA_NAME = "information_schema";
+
  private final SystemTablesMetadata systemMetadata;
  private final ConcurrentMap<String, ConnectorMetadataEntry> informationSchemasByCatalog = new ConcurrentHashMap<>();
  private final ConcurrentMap<String, ConnectorMetadataEntry> connectorsByCatalog = new ConcurrentHashMap<>();
@@ -189,9 +192,9 @@ public Optional<TableHandle> getTableHandle(ConnectorSession session, QualifiedT
  {
  checkNotNull(table, "table is null");
 
- SchemaTableName tableName = table.asSchemaTableName();
- for (ConnectorMetadataEntry entry : allConnectorsFor(table.getCatalogName())) {
- ConnectorTableHandle tableHandle = entry.getMetadata().getTableHandle(session, tableName);
+ ConnectorMetadataEntry entry = getConnectorFor(table);
+ if (entry != null) {
+ ConnectorTableHandle tableHandle = entry.getMetadata().getTableHandle(session, table.asSchemaTableName());
  if (tableHandle != null) {
  return Optional.of(new TableHandle(entry.getConnectorId(), tableHandle));
  }
@@ -405,8 +408,9 @@ public Map<QualifiedTableName, ViewDefinition> getViews(ConnectorSession session
  @Override
  public Optional<ViewDefinition> getView(ConnectorSession session, QualifiedTableName viewName)
  {
- SchemaTablePrefix prefix = viewName.asSchemaTableName().toSchemaTablePrefix();
- for (ConnectorMetadataEntry entry : allConnectorsFor(viewName.getCatalogName())) {
+ ConnectorMetadataEntry entry = getConnectorFor(viewName);
+ if (entry != null) {
+ SchemaTablePrefix prefix = viewName.asSchemaTableName().toSchemaTablePrefix();
  Map<SchemaTableName, String> views = entry.getMetadata().getViews(session, prefix);
  String view = views.get(viewName.asSchemaTableName());
  if (view != null) {
@@ -473,6 +477,21 @@ private List<ConnectorMetadataEntry> allConnectorsFor(String catalogName)
  return builder.build();
  }
 
+ private ConnectorMetadataEntry getConnectorFor(QualifiedTableName name)
+ {
+ String catalog = name.getCatalogName();
+ String schema = name.getSchemaName();
+
+ if (schema.equals(SYS_SCHEMA_NAME)) {
+ return new ConnectorMetadataEntry(SystemTablesManager.CONNECTOR_ID, systemMetadata);
+ }
+ else if (schema.equals(INFORMATION_SCHEMA_NAME)) {
+ return informationSchemasByCatalog.get(catalog);
+ }
+
+ return connectorsByCatalog.get(catalog);
+ }
+
  private ConnectorMetadata lookupConnectorFor(TableHandle tableHandle)
  {
  return getConnectorMetadata(tableHandle.getConnectorId());