HIVE-28765: Iceberg: Incorrect partition statistics on time travel + partition evolution

[okumin]

What changes were proposed in this pull request?

https://issues.apache.org/jira/browse/HIVE-28765

We use not partition stats but table stats when we access a complicated table with tagging or branching.

Why are the changes needed?

We would like to improve the query plan for a time-travel read with tagging and branching.

Does this PR introduce any user-facing change?

No

Is the change a dependency upgrade?

No

How was this patch tested?

Updated an existing query file.

[deniskuzZ]

@okumin, could we use equals here?

  public boolean isPartitioned(org.apache.hadoop.hive.ql.metadata.Table hmsTable) {
    if (!hmsTable.getTTable().isSetId()) {
      return false;
    }
    Table table = IcebergTableUtil.getTable(conf, hmsTable.getTTable());
    Snapshot snapshot = IcebergTableUtil.getTableSnapshot(table, hmsTable);
    
    boolean isTimeTravelOrBranch = snapshot != null && snapshot.equals(table.currentSnapshot());
    if (isTimeTravelOrBranch && hasUndergonePartitionEvolution(table)) {
      return false;
    }
    return table.spec().isPartitioned();
  }

[okumin]

I agree that it is simpler and tolerant with unexpected snapshots, such as having the same snapshot id but different timestamps.
https://github.com/apache/iceberg/blob/c338323b2e9cd8a862fdf328ceacc1b59ea6275a/core/src/main/java/org/apache/iceberg/BaseSnapshot.java#L320-L332

I updated it. I kept the variable name, isTimeTravel, assuming reading a different snapshot using tag/branch sounds like a time-travel query.

[deniskuzZ]

forked branch could be ahead of main, so I wouldn't call it time-travel

[okumin]

I grabbed your point. I applied a slight modification to the variable name.
1ac16b2

[deniskuzZ]

+1, pending tests

[sonarqubecloud]

Quality Gate passed

Issues
5 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[okumin]

@deniskuzZ Thanks for reviewing this pull request!