haridsv commented on code in PR #2298:
URL: https://github.com/apache/phoenix/pull/2298#discussion_r2458977305
##########
phoenix-core-client/src/main/java/org/apache/phoenix/compile/RowProjector.java:
##########
@@ -206,4 +235,55 @@ public void reset() {
projector.getExpression().reset();
}
}
+
+ /**
+ * PHOENIX-6644: Creates a new RowProjector with additional column name
mappings merged from
+ * another projector. This is useful when an optimized query (e.g., using an
index) rewrites
+ * column references but we want to preserve the original column names for
+ * ResultSet.getString(columnName) compatibility. For example, when a view
has "WHERE v1 = 'a'"
+ * and an index is used, the optimizer may rewrite "SELECT v1 FROM view" to
"SELECT 'a' FROM
+ * index". This method adds the original column name "v1" to the
reverseIndex so
+ * ResultSet.getString("v1") continues to work.
+ * @param sourceProjector the projector containing original column name
mappings to preserve
+ * @return a new RowProjector with merged column name mappings
+ */
+ public RowProjector mergeColumnNameMappings(RowProjector sourceProjector) {
+ if (this.columnProjectors.size() !=
sourceProjector.columnProjectors.size()) {
+ return this;
+ }
+
+ ListMultimap<String, Integer> additionalMappings =
ArrayListMultimap.create();
+
+ for (int i = 0; i < sourceProjector.columnProjectors.size(); i++) {
+ ColumnProjector sourceCol = sourceProjector.columnProjectors.get(i);
+ ColumnProjector currentCol = this.columnProjectors.get(i);
+
+ // Only add source labels if they're different from current labels
+ // This preserves original names like "v1" when optimizer rewrites to
"'a'"
+ String sourceLabel = sourceCol.getLabel();
+ String currentLabel = currentCol.getLabel();
+
+ if (!sourceLabel.equals(currentLabel)) {
+ additionalMappings.put(sourceLabel, i);
+ }
+
+ // Also add qualified name from source if different
+ if (!sourceCol.getTableName().isEmpty()) {
+ String sourceQualifiedName =
+ SchemaUtil.getColumnName(sourceCol.getTableName(),
sourceCol.getLabel());
+ String currentQualifiedName = currentCol.getTableName().isEmpty()
+ ? ""
+ : SchemaUtil.getColumnName(currentCol.getTableName(),
currentCol.getLabel());
+
+ if (!sourceQualifiedName.equals(currentQualifiedName)) {
+ additionalMappings.put(sourceQualifiedName, i);
+ }
+ }
+ }
Review Comment:
It appears that this can be simplified a bit if you consider the following 2
facts:
- Since qualified name includes label, it is guaranteed to be difference
when label is found to be different at line 266, so there is no need to check.
- If label is same, then the only qualified name can be different is when
the table name is different, so you can skip the construction of
`currentQualifiedName` as it is only needed for the comparison.
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