pvary commented on code in PR #12629:
URL: https://github.com/apache/iceberg/pull/12629#discussion_r2016416364
##########
data/src/main/java/org/apache/iceberg/data/PartitionStatsHandler.java:
##########
@@ -135,20 +146,112 @@ public static PartitionStatisticsFile
computeAndWriteStatsFile(Table table) thro
*/
public static PartitionStatisticsFile computeAndWriteStatsFile(Table table,
long snapshotId)
throws IOException {
+ return computeAndWrite(table, snapshotId, true /* recompute */);
+ }
+
+ /**
+ * Incrementally computes the stats after the snapshot that has partition
stats file till the
+ * given snapshot and writes the combined result into a {@link
PartitionStatisticsFile} after
+ * merging the stats.
+ *
+ * @param table The {@link Table} for which the partition statistics is
computed.
+ * @param snapshotId snapshot for which partition statistics are computed.
+ * @return {@link PartitionStatisticsFile} for the given snapshot, or null
if no statistics are
+ * present.
+ */
+ public static PartitionStatisticsFile computeAndWriteStatsFileIncremental(
+ Table table, long snapshotId) throws IOException {
+ return computeAndWrite(table, snapshotId, false /* recompute */);
+ }
+
+ private static PartitionStatisticsFile computeAndWrite(
+ Table table, long snapshotId, boolean recompute) throws IOException {
+ Preconditions.checkArgument(table != null, "Table cannot be null");
Snapshot snapshot = table.snapshot(snapshotId);
Preconditions.checkArgument(snapshot != null, "Snapshot not found: %s",
snapshotId);
- Collection<PartitionStats> stats = PartitionStatsUtil.computeStats(table,
snapshot);
- if (stats.isEmpty()) {
+ StructType partitionType = Partitioning.partitionType(table);
+ PartitionMap<PartitionStats> resultStatsMap =
+ computeStats(table, snapshot, partitionType, recompute);
+ if (resultStatsMap.isEmpty()) {
return null;
}
- StructType partitionType = Partitioning.partitionType(table);
- List<PartitionStats> sortedStats = PartitionStatsUtil.sortStats(stats,
partitionType);
+ List<PartitionStats> sortedStats =
+ PartitionStatsUtil.sortStats(resultStatsMap.values(), partitionType);
return writePartitionStatsFile(
table, snapshot.snapshotId(), schema(partitionType), sortedStats);
}
+ private static PartitionMap<PartitionStats> computeStats(
+ Table table, Snapshot snapshot, StructType partitionType, boolean
recompute)
+ throws IOException {
+ if (recompute) {
+ return PartitionStatsUtil.computeStats(table, null, snapshot);
+ }
+
+ PartitionStatisticsFile statisticsFile = latestStatsFile(table,
snapshot.snapshotId());
+ if (statisticsFile == null) {
+ LOG.info("Previous stats not found. Computing the stats for whole
table.");
+ return PartitionStatsUtil.computeStats(table, null, snapshot);
+ }
+
+ PartitionMap<PartitionStats> statsMap = PartitionMap.create(table.specs());
+ // read previous stats, note that partition field will be read as
GenericRecord
+ try (CloseableIterable<PartitionStats> oldStats =
+ readPartitionStatsFile(schema(partitionType),
Files.localInput(statisticsFile.path()))) {
+ oldStats.forEach(
+ partitionStats ->
+ statsMap.put(partitionStats.specId(),
partitionStats.partition(), partitionStats));
+ }
+
+ // incrementally compute the new stats, partition field will be written as
PartitionData
+ PartitionMap<PartitionStats> incrementalStatsMap =
+ PartitionStatsUtil.computeStats(
+ table, table.snapshot(statisticsFile.snapshotId()), snapshot);
+
+ // convert PartitionData into GenericRecord and merge stats
+ incrementalStatsMap.forEach(
+ (key, value) ->
+ statsMap.merge(
+ Pair.of(key.first(), partitionDataToRecord((PartitionData)
key.second())),
+ value,
+ (existingEntry, newEntry) -> {
+ existingEntry.appendStats(newEntry);
+ return existingEntry;
+ }));
+
+ return statsMap;
+ }
+
+ private static GenericRecord partitionDataToRecord(PartitionData data) {
+ GenericRecord record = GenericRecord.create(data.getPartitionType());
+ for (int index = 0; index < record.size(); index++) {
+ record.set(index, data.get(index));
+ }
+
+ return record;
+ }
+
+ private static PartitionStatisticsFile latestStatsFile(Table table, long
snapshotId) {
Review Comment:
Do we have test for this code?
It is not too complicated, but non-trivial. Maybe at lease a test which
depends on the logic would be good
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