apache/iceberg · error · UnsupportedOperationException

Cannot remove or replace rows in a

Error message

Cannot remove or replace rows in a %s table

What it means

Iceberg throws this UnsupportedOperationException when newRowDelta() is called on a read-only table. RowDelta commits data and delete files (row-level changes), which BaseReadOnlyTable subclasses never allow. The descriptor names the read-only table kind.

Solutions

1. Build the RowDelta on the writable data table loaded via catalog.loadTable(identifier).
2. Validate the Table reference is a real data table before instantiating writers.
3. Use RowDelta only for v2 tables; ensure the target table has format version 2.

Example fix

// before
table.snapshots().newRowDelta().addRows(writer).commit();

// after
Table dataTable = catalog.loadTable(TableIdentifier.of("db", "tbl"));
dataTable.newRowDelta().addRows(writer).commit();

if (isMetadataTableName(table.name())) { throw new IllegalArgumentException("Cannot apply row deltas to metadata table " + table.name()); }

boolean canWriteRowDelta = !(table instanceof BaseReadOnlyTable); // ensure handle came from Catalog.loadTable

try {
  table.newRowDelta().addRows(writer).commit();
} catch (UnsupportedOperationException e) {
  log.error("RowDelta is not supported on read-only table {}", table.name(), e);
}

When it happens

Trigger: Calling table.newRowDelta().addRows(...).addDeletes(...).commit() on a metadata table or any BaseReadOnlyTable subclass instance.

Common situations: Row-level delete writers (e.g. CDC or merge-on-read writers) that were given a metadata-table handle instead of the data table.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Cannot append to a table
• Cannot create transactions for a
• Cannot delete from a
• Cannot expire snapshots from a
• Cannot manage snapshots in a

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/1d5d6a45ef77893d. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/apache/iceberg/BaseReadOnlyTable.java:82

  @Override
  public RewriteFiles newRewrite() {
    throw new UnsupportedOperationException("Cannot rewrite in a " + descriptor + " table");
  }

  @Override
  public RewriteManifests rewriteManifests() {
    throw new UnsupportedOperationException(
        "Cannot rewrite manifests in a " + descriptor + " table");
  }

  @Override
  public OverwriteFiles newOverwrite() {
    throw new UnsupportedOperationException("Cannot overwrite in a " + descriptor + " table");
  }

  @Override
  public RowDelta newRowDelta() {
    throw new UnsupportedOperationException(
        "Cannot remove or replace rows in a " + descriptor + " table");
  }

  @Override
  public ReplacePartitions newReplacePartitions() {
    throw new UnsupportedOperationException(
        "Cannot replace partitions in a " + descriptor + " table");
  }

  @Override
  public DeleteFiles newDelete() {
    throw new UnsupportedOperationException("Cannot delete from a " + descriptor + " table");
  }

  @Override
  public UpdateStatistics updateStatistics() {
    throw new UnsupportedOperationException(
        "Cannot update statistics of a " + descriptor + " table");

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