Examples with ScanRange com.mapr.db.scan.ScanRange used on opensource projects

Example 1 with ScanRange

use of com.mapr.db.scan.ScanRange in project drill by apache.

the class JsonTableGroupScan method getRegionsToScan.

protected NavigableMap<TabletFragmentInfo, String> getRegionsToScan(int scanRangeSizeMB) {
    // If regionsToScan already computed, just return.
    double estimatedRowCount = ROWCOUNT_UNKNOWN;
    if (doNotAccessRegionsToScan == null) {
        final Table t = this.formatPlugin.getJsonTableCache().getTable(scanSpec.getTableName(), scanSpec.getIndexDesc(), getUserName());
        final MetaTable metaTable = t.getMetaTable();
        QueryCondition scanSpecCondition = scanSpec.getCondition();
        List<ScanRange> scanRanges = (scanSpecCondition == null) ? metaTable.getScanRanges(scanRangeSizeMB) : metaTable.getScanRanges(scanSpecCondition, scanRangeSizeMB);
        logger.debug("getRegionsToScan() with scanSpec {}: table={}, index={}, condition={}, sizeMB={}, #ScanRanges={}", System.identityHashCode(scanSpec), scanSpec.getTableName(), scanSpec.getIndexName(), scanSpec.getCondition() == null ? "null" : scanSpec.getCondition(), scanRangeSizeMB, scanRanges == null ? "null" : scanRanges.size());
        final TreeMap<TabletFragmentInfo, String> regionsToScan = new TreeMap<>();
        if (isIndexScan()) {
            String idxIdentifier = stats.buildUniqueIndexIdentifier(scanSpec.getIndexDesc().getPrimaryTablePath(), scanSpec.getIndexDesc().getIndexName());
            if (stats.isStatsAvailable()) {
                estimatedRowCount = stats.getRowCount(scanSpec.getCondition(), idxIdentifier);
            }
        } else {
            if (stats.isStatsAvailable()) {
                estimatedRowCount = stats.getRowCount(scanSpec.getCondition(), null);
            }
        }
        // If limit pushdown has occurred - factor it in the rowcount
        if (this.maxRecordsToRead > 0) {
            estimatedRowCount = Math.min(estimatedRowCount, this.maxRecordsToRead);
        }
        // If the estimated row count > 0 then scan ranges must be > 0
        Preconditions.checkState(estimatedRowCount == ROWCOUNT_UNKNOWN || estimatedRowCount == 0 || (scanRanges != null && scanRanges.size() > 0), String.format("#Scan ranges should be greater than 0 since estimated rowcount=[%f]", estimatedRowCount));
        if (scanRanges != null && scanRanges.size() > 0) {
            // set the start-row of the scanspec as the start-row of the first scan range
            ScanRange firstRange = scanRanges.get(0);
            QueryCondition firstCondition = firstRange.getCondition();
            byte[] firstStartRow = ((ConditionImpl) firstCondition).getRowkeyRanges().get(0).getStartRow();
            scanSpec.setStartRow(firstStartRow);
            // set the stop-row of ScanSpec as the stop-row of the last scan range
            ScanRange lastRange = scanRanges.get(scanRanges.size() - 1);
            QueryCondition lastCondition = lastRange.getCondition();
            List<RowkeyRange> rowkeyRanges = ((ConditionImpl) lastCondition).getRowkeyRanges();
            byte[] lastStopRow = rowkeyRanges.get(rowkeyRanges.size() - 1).getStopRow();
            scanSpec.setStopRow(lastStopRow);
            for (ScanRange range : scanRanges) {
                TabletInfoImpl tabletInfoImpl = (TabletInfoImpl) range;
                regionsToScan.put(new TabletFragmentInfo(tabletInfoImpl), range.getLocations()[0]);
            }
        }
        setRegionsToScan(regionsToScan);
    }
    return doNotAccessRegionsToScan;
}

Example 2 with ScanRange

use of com.mapr.db.scan.ScanRange in project drill by apache.

the class JsonTableRangePartitionFunction method initialize.

public void initialize(MapRDBFormatPlugin plugin) {
    // get the table handle from the table cache
    Table table = plugin.getJsonTableCache().getTable(tableName, userName);
    // Get all scan ranges for the primary table.
    // The reason is the row keys could typically belong to any one of the tablets of the table, so
    // there is no use trying to get only limited set of scan ranges.
    // NOTE: here we use the restrictedScanRangeSizeMB because the range partitioning should be parallelized
    // based on the number of scan ranges on the RestrictedJsonTableGroupScan.
    List<ScanRange> ranges = table.getMetaTable().getScanRanges(plugin.getRestrictedScanRangeSizeMB());
    this.startKeys = Lists.newArrayList();
    this.stopKeys = Lists.newArrayList();
    logger.debug("Num scan ranges for table {} = {}", table.getName(), ranges.size());
    int count = 0;
    for (ScanRange r : ranges) {
        QueryCondition condition = r.getCondition();
        List<RowkeyRange> rowkeyRanges = ((ConditionImpl) condition).getRowkeyRanges();
        byte[] start = rowkeyRanges.get(0).getStartRow();
        byte[] stop = rowkeyRanges.get(rowkeyRanges.size() - 1).getStopRow();
        Preconditions.checkNotNull(start, String.format("Encountered a null start key at position %d for scan range condition %s.", count, condition.toString()));
        Preconditions.checkNotNull(stop, String.format("Encountered a null stop key at position %d for scan range condition %s.", count, condition.toString()));
        if (count > 0) {
            // after the first start key, rest should be non-empty
            Preconditions.checkState(!(Bytes.equals(start, MapRConstants.EMPTY_BYTE_ARRAY)), String.format("Encountered an empty start key at position %d", count));
        }
        if (count < ranges.size() - 1) {
            // except for the last stop key, rest should be non-empty
            Preconditions.checkState(!(Bytes.equals(stop, MapRConstants.EMPTY_BYTE_ARRAY)), String.format("Encountered an empty stop key at position %d", count));
        }
        startKeys.add(start);
        stopKeys.add(stop);
        count++;
    }
    // check validity; only need to check one of the lists since they are populated together
    Preconditions.checkArgument(startKeys.size() > 0, "Found empty list of start/stopKeys.");
    Preconditions.checkState(startKeys.size() == ranges.size(), String.format("Mismatch between the lengths: num start keys = %d, num scan ranges = %d", startKeys.size(), ranges.size()));
    Preconditions.checkState(stopKeys.size() == ranges.size(), String.format("Mismatch between the lengths: num stop keys = %d, num scan ranges = %d", stopKeys.size(), ranges.size()));
}