gemini-code-assist[bot] commented on code in PR #39155:
URL: https://github.com/apache/beam/pull/39155#discussion_r3493575765
##########
sdks/java/io/iceberg/src/main/java/org/apache/beam/sdk/io/iceberg/AssignDestinationsAndPartitions.java:
##########
@@ -84,6 +84,7 @@ static class AssignDoFn extends DoFn<Row, KV<Row, Row>> {
private transient @MonotonicNonNull Map<String, PartitionKey>
partitionKeys;
private transient @MonotonicNonNull Map<String, BeamRowWrapper> wrappers;
private transient @MonotonicNonNull Map<String, Instant> lastRefreshTimes;
+ private transient @MonotonicNonNull Map<String, Row> keyCache;
Review Comment:
Using a single flat map with a concatenated string key (`tableIdentifier +
"|" + partitionPath`) requires allocating a new `String` object for every
single input element, even on cache hits. Since this DoFn processes millions of
rows, this overhead can be avoided by using a nested map structure:
`Map<String, Map<String, Row>>`.
```suggestion
private transient @MonotonicNonNull Map<String, Map<String, Row>>
keyCache;
```
##########
sdks/java/io/iceberg/src/main/java/org/apache/beam/sdk/io/iceberg/AssignDestinationsAndPartitions.java:
##########
@@ -175,8 +177,13 @@ public void processElement(
String partitionPath = partitionKey.toPath();
- Row destAndPartition =
- Row.withSchema(OUTPUT_SCHEMA).addValues(tableIdentifier,
partitionPath).build();
+ String cacheKey = tableIdentifier + "|" + partitionPath;
+ Row destAndPartition = checkStateNotNull(keyCache).get(cacheKey);
+ if (destAndPartition == null) {
+ destAndPartition =
+ Row.withSchema(OUTPUT_SCHEMA).addValues(tableIdentifier,
partitionPath).build();
+ keyCache.put(cacheKey, destAndPartition);
+ }
Review Comment:
Instead of concatenating `tableIdentifier` and `partitionPath` into a new
`String` on every element, use a nested map lookup. This avoids any object
allocation on cache hits, which is the common case.
```java
Map<String, Map<String, Row>> cache = checkStateNotNull(keyCache);
Map<String, Row> tableCache = cache.get(tableIdentifier);
if (tableCache == null) {
tableCache = new HashMap<>();
cache.put(tableIdentifier, tableCache);
}
Row destAndPartition = tableCache.get(partitionPath);
if (destAndPartition == null) {
destAndPartition =
Row.withSchema(OUTPUT_SCHEMA).addValues(tableIdentifier,
partitionPath).build();
tableCache.put(partitionPath, destAndPartition);
}
```
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