presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/SemiTransactionalHiveMetastore.java/SemiTransactionalHiveMetastore/getTableStatistics
class SemiTransactionalHiveMetastore:    public synchronized PartitionStatistics getTableStatistics(HiveIdentity identity, String databaseName, String tableName)
    {
        checkReadable();
        Action<TableAndMore> tableAction = tableActions.get(new SchemaTableName(databaseName, tableName));
        if (tableAction == null) {
            return delegate.getTableStatistics(identity, databaseName, tableName);
        }
        switch (tableAction.getType()) {
            case ADD:
            case ALTER:
            case INSERT_EXISTING:
                return tableAction.getData().getStatistics();
            case DROP:
                return PartitionStatistics.empty();
            default:
                throw new IllegalStateException("Unknown action type");
        }
    }