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https://issues.apache.org/jira/browse/DRILL-6385?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16569606#comment-16569606
]
ASF GitHub Bot commented on DRILL-6385:
---------------------------------------
sohami commented on a change in pull request #1334: DRILL-6385: Support JPPD
feature
URL: https://github.com/apache/drill/pull/1334#discussion_r207749408
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/ScanBatch.java
##########
@@ -226,6 +259,93 @@ public IterOutcome next() {
}
}
+ /**
+ *
+ * @return true means rows are filtered by the RuntimeFilter, false means
not affected by the RuntimeFilter.
+ * @throws SchemaChangeException
+ */
+ private boolean applyRuntimeFilter() throws SchemaChangeException {
+ RuntimeFilterWritable runtimeFilterWritable = context.getRuntimeFilter();
+ if (runtimeFilterWritable == null) {
+ return false;
+ }
+ if (recordCount <= 0) {
+ return false;
+ }
+ List<BloomFilter> bloomFilters = runtimeFilterWritable.unwrap();
+ if (hash64 == null) {
+ ValueVectorHashHelper hashHelper = new ValueVectorHashHelper(this,
context);
+ try {
+ //generate hash helper
+ this.toFilterFields =
runtimeFilterWritable.getRuntimeFilterBDef().getProbeFieldsList();
+ List<LogicalExpression> hashFieldExps = new ArrayList<>();
+ List<TypedFieldId> typedFieldIds = new ArrayList<>();
+ for (String toFilterField : toFilterFields) {
+ SchemaPath schemaPath = new SchemaPath(new
PathSegment.NameSegment(toFilterField), ExpressionPosition.UNKNOWN);
+ TypedFieldId typedFieldId = container.getValueVectorId(schemaPath);
+ this.field2id.put(toFilterField, typedFieldId.getFieldIds()[0]);
+ typedFieldIds.add(typedFieldId);
+ ValueVectorReadExpression toHashFieldExp = new
ValueVectorReadExpression(typedFieldId);
+ hashFieldExps.add(toHashFieldExp);
+ }
+ hash64 = hashHelper.getHash64(hashFieldExps.toArray(new
LogicalExpression[hashFieldExps.size()]), typedFieldIds.toArray(new
TypedFieldId[typedFieldIds.size()]));
+ } catch (Exception e) {
+ throw UserException.internalError(e).build(logger);
+ }
+ }
+ selectionVector2.allocateNew(recordCount);
+ //To make each independent bloom filter work together to construct a final
filter result: BitSet.
+ BitSet bitSet = new BitSet(recordCount);
+ for (int i = 0; i < toFilterFields.size(); i++) {
+ BloomFilter bloomFilter = bloomFilters.get(i);
+ String fieldName = toFilterFields.get(i);
+ computeBitSet(field2id.get(fieldName), bloomFilter, bitSet);
+ }
+
+ int svIndex = 0;
+ int tmpFilterRows = 0;
+ for (int i = 0; i < recordCount; i++) {
+ boolean contain = bitSet.get(i);
+ if (contain) {
+ selectionVector2.setIndex(svIndex, i);
+ svIndex++;
+ } else {
+ tmpFilterRows++;
+ }
+ }
+ selectionVector2.setRecordCount(svIndex);
+ if (tmpFilterRows > 0 && tmpFilterRows == recordCount) {
+ //all rows of the batch was filtered
+ recordCount = 0;
+ selectionVector2.clear();
+ logger.debug("filter {} rows by the RuntimeFilter", tmpFilterRows);
+ //return false to avoid unnecessary SV2 memory copy work
+ return false;
+ }
+ if (tmpFilterRows > 0 && tmpFilterRows != recordCount ) {
+ //partial of the rows was filtered
+ totalFilterRows = totalFilterRows + tmpFilterRows;
+ recordCount = svIndex;
+ logger.debug("filter {} rows by the RuntimeFilter", tmpFilterRows);
+ return true;
+ }
+ selectionVector2.clear();
Review comment:
In this case it means none of the rows are filtered out.
There is a bug here. Consider a case when few rows where filtered for one
batch so `applyRuntimeFilter` will return true with `selectionVector2`
correctly allocated and set. Since this is first batch with some filtered rows
the caller will create a batch with SV2 Mode and set `runtimeFiltered=true`.
Now the next batch came in for which none of the rows were filtered. Hence we
will clear **selectionVector2** here but the schema of returned batch is still
SV2Mode with record count set to number of rows in the batches. The downstream
operator will throw IOB while trying to access the first record since
**selectionVector2** buffer is cleared.
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> Support JPPD (Join Predicate Push Down)
> ---------------------------------------
>
> Key: DRILL-6385
> URL: https://issues.apache.org/jira/browse/DRILL-6385
> Project: Apache Drill
> Issue Type: New Feature
> Components: Server, Execution - Flow
> Affects Versions: 1.14.0
> Reporter: weijie.tong
> Assignee: weijie.tong
> Priority: Major
>
> This feature is to support the JPPD (Join Predicate Push Down). It will
> benefit the HashJoin ,Broadcast HashJoin performance by reducing the number
> of rows to send across the network ,the memory consumed. This feature is
> already supported by Impala which calls it RuntimeFilter
> ([https://www.cloudera.com/documentation/enterprise/5-9-x/topics/impala_runtime_filtering.html]).
> The first PR will try to push down a bloom filter of HashJoin node to
> Parquet’s scan node. The propose basic procedure is described as follow:
> # The HashJoin build side accumulate the equal join condition rows to
> construct a bloom filter. Then it sends out the bloom filter to the foreman
> node.
> # The foreman node accept the bloom filters passively from all the fragments
> that has the HashJoin operator. It then aggregates the bloom filters to form
> a global bloom filter.
> # The foreman node broadcasts the global bloom filter to all the probe side
> scan nodes which maybe already have send out partial data to the hash join
> nodes(currently the hash join node will prefetch one batch from both sides ).
> 4. The scan node accepts a global bloom filter from the foreman node.
> It will filter the rest rows satisfying the bloom filter.
>
> To implement above execution flow, some main new notion described as below:
> 1. RuntimeFilter
> It’s a filter container which may contain BloomFilter or MinMaxFilter.
> 2. RuntimeFilterReporter
> It wraps the logic to send hash join’s bloom filter to the foreman.The
> serialized bloom filter will be sent out through the data tunnel.This object
> will be instanced by the FragmentExecutor and passed to the
> FragmentContext.So the HashJoin operator can obtain it through the
> FragmentContext.
> 3. RuntimeFilterRequestHandler
> It is responsible to accept a SendRuntimeFilterRequest RPC to strip the
> actual BloomFilter from the network. It then translates this filter to the
> WorkerBee’s new interface registerRuntimeFilter.
> Another RPC type is BroadcastRuntimeFilterRequest. It will register the
> accepted global bloom filter to the WorkerBee by the registerRuntimeFilter
> method and then propagate to the FragmentContext through which the probe side
> scan node can fetch the aggregated bloom filter.
> 4.RuntimeFilterManager
> The foreman will instance a RuntimeFilterManager .It will indirectly get
> every RuntimeFilter by the WorkerBee. Once all the BloomFilters have been
> accepted and aggregated . It will broadcast the aggregated bloom filter to
> all the probe side scan nodes through the data tunnel by a
> BroadcastRuntimeFilterRequest RPC.
> 5. RuntimeFilterEnableOption
> A global option will be added to decide whether to enable this new feature.
>
> Welcome suggestion and advice from you.The related PR will be presented as
> soon as possible.
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