Examples with PreJoinableClause org.apache.druid.query.planning.PreJoinableClause used on opensource projects

Example 16 with PreJoinableClause

use of org.apache.druid.query.planning.PreJoinableClause in project druid by druid-io.

the class JoinableFactoryWrapper method createSegmentMapFn.

/**
 * Creates a Function that maps base segments to {@link HashJoinSegment} if needed (i.e. if the number of join
 * clauses is > 0). If mapping is not needed, this method will return {@link Function#identity()}.
 *
 * @param baseFilter         Filter to apply before the join takes place
 * @param clauses            Pre-joinable clauses
 * @param cpuTimeAccumulator An accumulator that we will add CPU nanos to; this is part of the function to encourage
 *                           callers to remember to track metrics on CPU time required for creation of Joinables
 * @param query              The query that will be run on the mapped segments. Usually this should be
 *                           {@code analysis.getBaseQuery().orElse(query)}, where "analysis" is a
 *                           {@link DataSourceAnalysis} and "query" is the original
 *                           query from the end user.
 */
public Function<SegmentReference, SegmentReference> createSegmentMapFn(@Nullable final Filter baseFilter, final List<PreJoinableClause> clauses, final AtomicLong cpuTimeAccumulator, final Query<?> query) {
    // compute column correlations here and RHS correlated values
    return JvmUtils.safeAccumulateThreadCpuTime(cpuTimeAccumulator, () -> {
        if (clauses.isEmpty()) {
            return Function.identity();
        } else {
            final JoinableClauses joinableClauses = JoinableClauses.createClauses(clauses, joinableFactory);
            final JoinFilterRewriteConfig filterRewriteConfig = JoinFilterRewriteConfig.forQuery(query);
            // Pick off any join clauses that can be converted into filters.
            final Set<String> requiredColumns = query.getRequiredColumns();
            final Filter baseFilterToUse;
            final List<JoinableClause> clausesToUse;
            if (requiredColumns != null && filterRewriteConfig.isEnableRewriteJoinToFilter()) {
                final Pair<List<Filter>, List<JoinableClause>> conversionResult = convertJoinsToFilters(joinableClauses.getJoinableClauses(), requiredColumns, Ints.checkedCast(Math.min(filterRewriteConfig.getFilterRewriteMaxSize(), Integer.MAX_VALUE)));
                baseFilterToUse = Filters.maybeAnd(Lists.newArrayList(Iterables.concat(Collections.singleton(baseFilter), conversionResult.lhs))).orElse(null);
                clausesToUse = conversionResult.rhs;
            } else {
                baseFilterToUse = baseFilter;
                clausesToUse = joinableClauses.getJoinableClauses();
            }
            // Analyze remaining join clauses to see if filters on them can be pushed down.
            final JoinFilterPreAnalysis joinFilterPreAnalysis = JoinFilterAnalyzer.computeJoinFilterPreAnalysis(new JoinFilterPreAnalysisKey(filterRewriteConfig, clausesToUse, query.getVirtualColumns(), Filters.maybeAnd(Arrays.asList(baseFilterToUse, Filters.toFilter(query.getFilter()))).orElse(null)));
            return baseSegment -> new HashJoinSegment(baseSegment, baseFilterToUse, clausesToUse, joinFilterPreAnalysis);
        }
    });
}