scarlin-cloudera commented on code in PR #4442:
URL: https://github.com/apache/hive/pull/4442#discussion_r1320422209
##########
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/ASTConverter.java:
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@@ -621,6 +644,80 @@ private ASTNode pkFkHint(int fkTableIndex, boolean
nonFkSideIsFiltered) {
}
}
+ private ASTNode createASTLateralView(TableFunctionScan tfs, Schema s,
+ QueryBlockInfo tableFunctionSource, String sqAlias) {
+ // The structure of the AST LATERAL VIEW will be:
+ //
+ // TOK_LATERAL_VIEW
+ // TOK_SELECT
+ // TOK_SELEXPR
+ // TOK_FUNCTION
+ // <udtf func>
+ // ...
+ // <col alias for function>
+ // TOK_TABALIAS
+ // <table alias for lateral view>
+
+ // set up the select for the parameters of the UDTF
+ List<ASTNode> children = new ArrayList<>();
+ // The UDTF function call within the table function scan will be of the
form:
+ // lateral(my_udtf_func(...), $0, $1, ...). For recreating the AST, we
need
+ // the inner "my_udtf_func".
+ RexCall lateralCall = (RexCall) tfs.getCall();
+ RexCall call = (RexCall) lateralCall.getOperands().get(0);
+ for (RexNode rn : call.getOperands()) {
+ ASTNode expr = rn.accept(new RexVisitor(s, rn 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.
+ lateralview.add(tableFunctionSource.ast);
+
+ return lateralview.node();
+ }
+
+ /**
+ * Check to see if we can optimize out the lateral view operators
+ * We do not need to use the lateral view syntax if all of the fields
+ * selected out of the table scan come from the UDTF call. No join
+ * is needed because all the fields come from the table level rather
+ * than the row level.
+ */
Review Comment:
Removed
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