Skip to content

Limit number of manifest files written by OPTIMIZE_MANIFESTS #26616

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Sep 15, 2025
Merged

Limit number of manifest files written by OPTIMIZE_MANIFESTS #26616

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 12 additions & 5 deletions plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergMetadata.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,6 @@
import org.apache.iceberg.SortField;
import org.apache.iceberg.SortOrder;
import org.apache.iceberg.StatisticsFile;
import org.apache.iceberg.StructLike;
import org.apache.iceberg.Table;
import org.apache.iceberg.TableProperties;
import org.apache.iceberg.TableScan;
Expand All @@ -200,6 +199,7 @@
import org.apache.iceberg.types.Types.NestedField;
import org.apache.iceberg.types.Types.StringType;
import org.apache.iceberg.types.Types.StructType;
import org.apache.iceberg.util.StructLikeWrapper;

import java.io.IOException;
import java.io.UncheckedIOException;
Expand All @@ -219,6 +219,7 @@
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.OptionalLong;
import java.util.Set;
Expand Down Expand Up @@ -2116,17 +2117,23 @@ private void executeOptimizeManifests(ConnectorSession session, IcebergTableExec
if (manifests.isEmpty()) {
return;
}
if (manifests.size() == 1 && manifests.getFirst().length() < icebergTable.operations().current().propertyAsLong(MANIFEST_TARGET_SIZE_BYTES, MANIFEST_TARGET_SIZE_BYTES_DEFAULT)) {
long manifestTargetSizeBytes = icebergTable.operations().current().propertyAsLong(MANIFEST_TARGET_SIZE_BYTES, MANIFEST_TARGET_SIZE_BYTES_DEFAULT);
if (manifests.size() == 1 && manifests.getFirst().length() < manifestTargetSizeBytes) {
return;
}
long totalManifestsSize = manifests.stream().mapToLong(ManifestFile::length).sum();
// Having too many open manifest writers can potentially cause OOM on the coordinator
long targetManifestClusters = Math.min(((totalManifestsSize + manifestTargetSizeBytes - 1) / manifestTargetSizeBytes), 100);
Copy link
Contributor

@oskar-szwajkowski oskar-szwajkowski Sep 12, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

would it make sense to make this 100 configurable?

Copy link
Member Author

@raunaqmorarka raunaqmorarka Sep 12, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

That's mainly there as a safety net. It should be rare to reach that number. We've seen coordinator OOM with large number of open manifest writers here, so don't want to expose it as a configureable to users.


beginTransaction(icebergTable);
RewriteManifests rewriteManifests = transaction.rewriteManifests();
Types.StructType structType = icebergTable.spec().partitionType();
rewriteManifests
.clusterBy(file -> {
// Use the first partition field as the clustering key
StructLike partition = file.partition();
return partition.size() > 1 ? Optional.ofNullable(partition.get(0, Object.class)) : partition;
// Cluster by partitions for better locality when reading data files
StructLikeWrapper partitionWrapper = StructLikeWrapper.forType(structType).set(file.partition());
// Limit the number of clustering buckets to avoid creating too many small manifest files
return Objects.hash(partitionWrapper) % targetManifestClusters;
})
.scanManifestsWith(icebergScanExecutor)
.commit();
Expand Down
38 changes: 27 additions & 11 deletions ...rc/test/java/io/trino/plugin/iceberg/procedure/TestIcebergOptimizeManifestsProcedure.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,7 @@ void testOptimizeManifestWithNullPartitions()
assertUpdate("ALTER TABLE " + table.getName() + " EXECUTE optimize_manifests");

assertThat(manifestFiles(table.getName()))
.hasSize(2)
.hasSize(1)
.doesNotContainAnyElementsOf(manifestFiles);

assertThat(query("SELECT * FROM " + table.getName()))
Expand Down Expand Up @@ -138,7 +138,7 @@ void testPartitionTable()

assertUpdate("ALTER TABLE " + table.getName() + " EXECUTE optimize_manifests");
assertThat(manifestFiles(table.getName()))
.hasSize(2)
.hasSize(1)
.doesNotContainAnyElementsOf(manifestFiles);

assertThat(query("SELECT * FROM " + table.getName()))
Expand All @@ -147,24 +147,40 @@ void testPartitionTable()
}

@Test
void testFirstPartitionField()
void testMultiplePartitioningColumns()
{
try (TestTable table = newTrinoTable("test_partition", "(id int, part int, nested int) WITH (partitioning = ARRAY['part', 'nested'])")) {
assertUpdate("INSERT INTO " + table.getName() + " VALUES (1, 10, 100)", 1);
assertUpdate("INSERT INTO " + table.getName() + " VALUES (2, 10, 200)", 1);
assertUpdate("INSERT INTO " + table.getName() + " VALUES (3, 20, 300)", 1);
assertUpdate("INSERT INTO " + table.getName() + " VALUES (4, 20, 400)", 1);
for (int i = 0; i < 30; i++) {
assertUpdate("INSERT INTO " + table.getName() + " VALUES (%d, %d, %d)".formatted(i, i % 10, i % 3), 1);
}

Set<String> manifestFiles = manifestFiles(table.getName());
assertThat(manifestFiles).hasSize(4);
assertThat(manifestFiles).hasSize(30);

assertUpdate("ALTER TABLE " + table.getName() + " EXECUTE optimize_manifests");
assertThat(manifestFiles(table.getName()))
Set<String> currentManifestFiles = manifestFiles(table.getName());
assertThat(currentManifestFiles)
.hasSize(1)
.doesNotContainAnyElementsOf(manifestFiles);

assertThat(query("SELECT COUNT(*) FROM " + table.getName()))
.matches("VALUES BIGINT '30'");

// Set small target size to force split
BaseTable icebergTable = loadTable(table.getName());
icebergTable.updateProperties()
.set("commit.manifest.target-size-bytes", "8000")
.commit();
manifestFiles = currentManifestFiles;
assertUpdate("ALTER TABLE " + table.getName() + " EXECUTE optimize_manifests");

currentManifestFiles = manifestFiles(table.getName());
assertThat(currentManifestFiles)
.hasSize(2)
.doesNotContainAnyElementsOf(manifestFiles);

assertThat(query("SELECT * FROM " + table.getName()))
.matches("VALUES (1, 10, 100), (2, 10, 200), (3, 20, 300), (4, 20, 400)");
assertThat(query("SELECT COUNT(*) FROM " + table.getName()))
.matches("VALUES BIGINT '30'");
}
}

Expand Down