explain

nik9000 · Jul 11, 2024 · 32a03b2 · 32a03b2
1 parent 0eb2958
commit 32a03b2
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/...plugin/esql/src/main/java/org/elasticsearch/xpack/esql/planner/LocalExecutionPlanner.java b/...plugin/esql/src/main/java/org/elasticsearch/xpack/esql/planner/LocalExecutionPlanner.java
@@ -65,6 +65,7 @@
 import org.elasticsearch.xpack.esql.enrich.EnrichLookupService;
 import org.elasticsearch.xpack.esql.evaluator.EvalMapper;
 import org.elasticsearch.xpack.esql.evaluator.command.GrokEvaluatorExtracter;
+import org.elasticsearch.xpack.esql.plan.logical.local.LocalRelation;
 import org.elasticsearch.xpack.esql.plan.physical.AggregateExec;
 import org.elasticsearch.xpack.esql.plan.physical.DissectExec;
 import org.elasticsearch.xpack.esql.plan.physical.EnrichExec;
@@ -553,10 +554,18 @@ private PhysicalOperation planHashJoin(HashJoinExec join, LocalExecutionPlannerC
         return source.with(new ProjectOperatorFactory(projection), layout);
     }
 
+    /**
+     * Convert a {@link HashJoinExec} into an {@link EvalOperatorFactory eval}.
+     * This is mostly useful when we're merging a table without any lookup fields
+     * and only works for single-row {@link LocalRelation}s.
+     */
     private PhysicalOperation planHashJoinAsEval(PhysicalOperation source, HashJoinExec join, LocalExecutionPlannerContext context) {
         Block[] blocks = join.joinData().supplier().get();
         try {
             for (int b = 0; b < join.joinData().output().size(); b++) {
+                if (blocks[b].getPositionCount() != 1) {
+                    throw new IllegalArgumentException("EVAL-based HashJoins only work for single-row tables");
+                }
                 Attribute target = join.joinData().output().get(b);
                 Literal lit = new Literal(target.source(), BlockUtils.toJavaObject(blocks[b], 0), target.dataType());
                 ExpressionEvaluator.Factory evaluatorSupplier = EvalMapper.toEvaluator(lit, source.layout);