Examples with BunchedMapMultiIterator com.apple.foundationdb.map.BunchedMapMultiIterator used on opensource projects

Example 1 with BunchedMapMultiIterator

use of com.apple.foundationdb.map.BunchedMapMultiIterator in project fdb-record-layer by FoundationDB.

the class TextIndexMaintainer method scan.

/**
 * Scan this index between a range of tokens. This index type requires that it be scanned only
 * by text token. The range to scan can otherwise be between any two entries in the list, and
 * scans over a prefix are supported by passing a value of <code>range</code> that uses
 * {@link com.apple.foundationdb.record.EndpointType#PREFIX_STRING PREFIX_STRING} as both endpoint types.
 * The keys returned in the index entry will include the token that was found in the index
 * when scanning in the column that is used for the text field of the index's root expression.
 * The value portion of each index entry will be a tuple whose first element is the position
 * list for that entry within its associated record's field.
 *
 * @param scanType the {@link IndexScanType type} of scan to perform
 * @param range the range to scan
 * @param continuation any continuation from a previous scan invocation
 * @param scanProperties skip, limit and other properties of the scan
 * @return a cursor over all index entries in <code>range</code>
 * @throws RecordCoreException if <code>scanType</code> is not {@link IndexScanType#BY_TEXT_TOKEN}
 * @see TextCursor
 */
@Nonnull
@Override
// not closing the returned cursor
@SuppressWarnings("squid:S2095")
public RecordCursor<IndexEntry> scan(@Nonnull IndexScanType scanType, @Nonnull TupleRange range, @Nullable byte[] continuation, @Nonnull ScanProperties scanProperties) {
    if (scanType != IndexScanType.BY_TEXT_TOKEN) {
        throw new RecordCoreException("Can only scan text index by text token.");
    }
    int textPosition = textFieldPosition(state.index.getRootExpression());
    TextSubspaceSplitter subspaceSplitter = new TextSubspaceSplitter(state.indexSubspace, textPosition + 1);
    Range byteRange = range.toRange();
    ScanProperties withAdjustedLimit = scanProperties.with(ExecuteProperties::clearSkipAndAdjustLimit);
    ExecuteProperties adjustedExecuteProperties = withAdjustedLimit.getExecuteProperties();
    // Callback for updating the byte scan limit
    final ByteScanLimiter byteScanLimiter = adjustedExecuteProperties.getState().getByteScanLimiter();
    final Consumer<KeyValue> callback = keyValue -> byteScanLimiter.registerScannedBytes(keyValue.getKey().length + keyValue.getValue().length);
    BunchedMapMultiIterator<Tuple, List<Integer>, Tuple> iterator = getBunchedMap(state.context).scanMulti(state.context.readTransaction(adjustedExecuteProperties.getIsolationLevel().isSnapshot()), state.indexSubspace, subspaceSplitter, byteRange.begin, byteRange.end, continuation, adjustedExecuteProperties.getReturnedRowLimit(), callback, scanProperties.isReverse());
    RecordCursor<IndexEntry> cursor = new TextCursor(iterator, state.store.getExecutor(), state.context, withAdjustedLimit, state.index);
    if (scanProperties.getExecuteProperties().getSkip() != 0) {
        cursor = cursor.skip(scanProperties.getExecuteProperties().getSkip());
    }
    return cursor;
}