Examples with MappedPageSource io.trino.split.MappedPageSource used on opensource projects

Example 1 with MappedPageSource

use of io.trino.split.MappedPageSource in project trino by trinodb.

the class SystemPageSourceProvider method createPageSource.

@Override
public ConnectorPageSource createPageSource(ConnectorTransactionHandle transaction, ConnectorSession session, ConnectorSplit split, ConnectorTableHandle table, List<ColumnHandle> columns, DynamicFilter dynamicFilter) {
    requireNonNull(columns, "columns is null");
    SystemTransactionHandle systemTransaction = (SystemTransactionHandle) transaction;
    SystemSplit systemSplit = (SystemSplit) split;
    SchemaTableName tableName = ((SystemTableHandle) table).getSchemaTableName();
    SystemTable systemTable = tables.getSystemTable(session, tableName).orElseThrow(() -> new TrinoException(NOT_FOUND, format("Table '%s' not found", tableName)));
    List<ColumnMetadata> tableColumns = systemTable.getTableMetadata().getColumns();
    Map<String, Integer> columnsByName = new HashMap<>();
    for (int i = 0; i < tableColumns.size(); i++) {
        ColumnMetadata column = tableColumns.get(i);
        if (columnsByName.put(column.getName(), i) != null) {
            throw new TrinoException(GENERIC_INTERNAL_ERROR, "Duplicate column name: " + column.getName());
        }
    }
    ImmutableList.Builder<Integer> userToSystemFieldIndex = ImmutableList.builder();
    for (ColumnHandle column : columns) {
        String columnName = ((SystemColumnHandle) column).getColumnName();
        Integer index = columnsByName.get(columnName);
        if (index == null) {
            throw new TrinoException(GENERIC_INTERNAL_ERROR, format("Column does not exist: %s.%s", tableName, columnName));
        }
        userToSystemFieldIndex.add(index);
    }
    TupleDomain<ColumnHandle> constraint = systemSplit.getConstraint();
    if (constraint.isNone()) {
        return new EmptyPageSource();
    }
    TupleDomain<Integer> newConstraint = systemSplit.getConstraint().transformKeys(columnHandle -> columnsByName.get(((SystemColumnHandle) columnHandle).getColumnName()));
    try {
        return new MappedPageSource(systemTable.pageSource(systemTransaction.getConnectorTransactionHandle(), session, newConstraint), userToSystemFieldIndex.build());
    } catch (UnsupportedOperationException e) {
        return new RecordPageSource(new MappedRecordSet(toRecordSet(systemTransaction.getConnectorTransactionHandle(), systemTable, session, newConstraint), userToSystemFieldIndex.build()));
    }
}