arjunashok commented on code in PR #34:
URL:
https://github.com/apache/cassandra-analytics/pull/34#discussion_r1466860439
##########
cassandra-analytics-core/src/main/java/org/apache/cassandra/spark/bulkwriter/RecordWriter.java:
##########
@@ -139,16 +137,33 @@ public List<StreamResult>
write(Iterator<Tuple2<DecoratedKey, Object[]>> sourceI
Map<String, Object> valueMap = new HashMap<>();
try
{
- Set<Range<BigInteger>> newRanges = new
HashSet<>(initialTokenRangeMapping.getRangeMap().asMapOfRanges().keySet());
+ // Use list to preserve order of ranges
+ List<Range<BigInteger>> newRanges = new
ArrayList<>(initialTokenRangeMapping.getRangeMap()
+
.asMapOfRanges()
+
.keySet());
Range<BigInteger> tokenRange = getTokenRange(taskContext);
- Set<Range<BigInteger>> subRanges = newRanges.contains(tokenRange) ?
-
Collections.singleton(tokenRange) :
-
getIntersectingSubRanges(newRanges, tokenRange);
+ List<Range<BigInteger>> subRanges = newRanges.contains(tokenRange)
?
Review Comment:
This is a O(n) lookup if we use a list (previously O(1)), since the API
returns all ranges and the partition's range can reside anywhere within it.
Also, this is exercised in most cases (without pending ranges).
##########
cassandra-analytics-core/src/main/java/org/apache/cassandra/spark/bulkwriter/RecordWriter.java:
##########
@@ -139,16 +137,33 @@ public List<StreamResult>
write(Iterator<Tuple2<DecoratedKey, Object[]>> sourceI
Map<String, Object> valueMap = new HashMap<>();
try
{
- Set<Range<BigInteger>> newRanges = new
HashSet<>(initialTokenRangeMapping.getRangeMap().asMapOfRanges().keySet());
+ // Use list to preserve order of ranges
+ List<Range<BigInteger>> newRanges = new
ArrayList<>(initialTokenRangeMapping.getRangeMap()
+
.asMapOfRanges()
+
.keySet());
Range<BigInteger> tokenRange = getTokenRange(taskContext);
- Set<Range<BigInteger>> subRanges = newRanges.contains(tokenRange) ?
-
Collections.singleton(tokenRange) :
-
getIntersectingSubRanges(newRanges, tokenRange);
+ List<Range<BigInteger>> subRanges = newRanges.contains(tokenRange)
?
+
Collections.singletonList(tokenRange) : // no overlaps
+
getIntersectingSubRanges(newRanges, tokenRange); // has overlaps; split into
sub-ranges
+ int currentRangeIndex = 0;
+ Range<BigInteger> currentRange = subRanges.get(currentRangeIndex);
Review Comment:
+1 for the optimization. Reduces the scope of subranges traversed for each
row.
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