scarlin-cloudera commented on code in PR #4442:
URL: https://github.com/apache/hive/pull/4442#discussion_r1244460449
##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/ASTConverter.java:
##########
@@ -577,6 +586,64 @@ private QueryBlockInfo convertSource(RelNode r) throws
CalciteSemanticException
ast = ASTBuilder.subQuery(left, sqAlias);
s = new Schema((Union) r, sqAlias);
}
+ } else if (r instanceof HiveTableFunctionScan &&
+ !canOptimizeOutLateralView((HiveTableFunctionScan) r)) {
+ // In the case where the RelNode is a HiveTableFunctionScan, first we
check
+ // to see if we can't optimize out the lateral view operator. We can
optimize the
+ // operator out if only the udtf fields are grabbed out of the RelNode.
If any
+ // of the base table fields need to be grabbed out, then a 'join' needs
to be done
+ // and we need the lateral view.
+ TableFunctionScan tfs = ((TableFunctionScan) r);
+
+ // retrieve the base table source.
+ QueryBlockInfo tableFunctionSource = convertSource(tfs.getInput(0));
+ String sqAlias = tableFunctionSource.schema.get(0).table;
+ // the schema will contain the base table source fields
+ s = new Schema(tfs, sqAlias);
+
+ // next, set up the select for the parameters of the UDTF
+ List<ASTNode> children = new ArrayList<>();
+ RexCall call = (RexCall) tfs.getCall();
+ for (RexNode rn : call.getOperands()) {
+ ASTNode expr = rn.accept(new RexVisitor(s, r instanceof RexLiteral,
+ select.getCluster().getRexBuilder()));
+ children.add(expr);
+ }
+ ASTNode function = buildUDTFAST(call.getOperator().getName(), children);
+
+ // Add the function to the SELEXPR
+ ASTBuilder selexpr = ASTBuilder.construct(HiveParser.TOK_SELEXPR,
"TOK_SELEXPR");
+ selexpr.add(function);
+
+ // Add only the table generated size columns to the select expr for the
function,
+ // skipping over the base table columns from the input side of the join.
+ int i = 0;
+ for (ColumnInfo c : s) {
+ if (i++ < tableFunctionSource.schema.size()) {
+ continue;
+ }
+ selexpr.add(HiveParser.Identifier, c.column);
+ }
+ // add the table alias for the lateral view.
+ ASTBuilder tabAlias = ASTBuilder.construct(HiveParser.TOK_TABALIAS,
"TOK_TABALIAS");
+ tabAlias.add(HiveParser.Identifier, sqAlias);
+
+ // add the table alias to the SEL_EXPR
+ selexpr.add(tabAlias.node());
+
+ // create the SELECT clause
+ ASTBuilder sel = ASTBuilder.construct(HiveParser.TOK_SELEXPR,
"TOK_SELECT");
+ sel.add(selexpr.node());
+
+ // place the SELECT clause under the LATERAL VIEW clause
+ ASTBuilder lateralview =
ASTBuilder.construct(HiveParser.TOK_LATERAL_VIEW, "TOK_LATERAL_VIEW");
+ lateralview.add(sel.node());
+
+ // finally, add the LATERAL VIEW clause under the left side source which
is the base table.
Review Comment:
Added comment
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