Columnar: make projectedColumnList an integer list. (#4869)

Co-authored-by: Jeff Davis <jefdavi@microsoft.com>

src/backend/columnar/columnar_reader.c

@@ -70,9 +70,8 @@ struct ColumnarReadState
 	StripeReadState *stripeReadState;
 
 	/*
-	 * List of Var pointers for columns in the query. We use this both for
+	 * Integer list of attribute numbers (1-indexed) for columns needed by the
-	 * getting vector of projected columns, and also when we want to build
+	 * query.
-	 * base constraint to find selected row chunks.
 	 */
 	List *projectedColumnList;
 
@@ -139,6 +138,8 @@ static Datum ColumnDefaultValue(TupleConstr *tupleConstraints,
 /*
  * ColumnarBeginRead initializes a columnar read operation. This function returns a
  * read handle that's used during reading rows and finishing the read operation.
+ *
+ * projectedColumnList is an integer list of attribute numbers (1-indexed).
  */
 ColumnarReadState *
 ColumnarBeginRead(Relation relation, TupleDesc tupleDescriptor,
@@ -415,12 +416,14 @@ ReadChunkGroupNextRow(ChunkGroupReadState *chunkGroupReadState, Datum *columnVal
 	 */
 	memset(columnNulls, true, sizeof(bool) * chunkGroupReadState->columnCount);
 
-	Var *projectedColumn = NULL;
+	int attno;
-	foreach_ptr(projectedColumn, chunkGroupReadState->projectedColumnList)
+	foreach_int(attno, chunkGroupReadState->projectedColumnList)
 	{
 		const ChunkData *chunkGroupData = chunkGroupReadState->chunkGroupData;
 		const int rowIndex = chunkGroupReadState->currentRow;
-		uint32 columnIndex = projectedColumn->varattno - 1;
+
+		/* attno is 1-indexed; existsArray is 0-indexed */
+		const uint32 columnIndex = attno - 1;
 
 		if (chunkGroupData->existsArray[columnIndex][rowIndex])
 		{
@@ -1010,12 +1013,12 @@ static bool *
 ProjectedColumnMask(uint32 columnCount, List *projectedColumnList)
 {
 	bool *projectedColumnMask = palloc0(columnCount * sizeof(bool));
-	ListCell *columnCell = NULL;
+	int attno;
 
-	foreach(columnCell, projectedColumnList)
+	foreach_int(attno, projectedColumnList)
 	{
-		Var *column = (Var *) lfirst(columnCell);
+		/* attno is 1-indexed; projectedColumnMask is 0-indexed */
-		uint32 columnIndex = column->varattno - 1;
+		int columnIndex = attno - 1;
 		projectedColumnMask[columnIndex] = true;
 	}
 

src/backend/columnar/columnar_tableam.c

@@ -119,34 +119,6 @@ static Datum * detoast_values(TupleDesc tupleDesc, Datum *orig_values, bool *isn
 /* Custom tuple slot ops used for columnar. Initialized in columnar_tableam_init(). */
 static TupleTableSlotOps TTSOpsColumnar;
 
-static List *
-RelationColumnList(TupleDesc tupdesc)
-{
-	List *columnList = NIL;
-
-	for (int i = 0; i < tupdesc->natts; i++)
-	{
-		Index varno = 1;
-		AttrNumber varattno = i + 1;
-		Oid vartype = tupdesc->attrs[i].atttypid;
-		int32 vartypmod = tupdesc->attrs[i].atttypmod;
-		Oid varcollid = tupdesc->attrs[i].attcollation;
-		Index varlevelsup = 0;
-
-		if (tupdesc->attrs[i].attisdropped)
-		{
-			continue;
-		}
-
-		Var *var = makeVar(varno, varattno, vartype, vartypmod,
-						   varcollid, varlevelsup);
-		columnList = lappend(columnList, var);
-	}
-
-	return columnList;
-}
-
-
 static const TupleTableSlotOps *
 columnar_slot_callbacks(Relation relation)
 {
@@ -161,9 +133,9 @@ columnar_beginscan(Relation relation, Snapshot snapshot,
 				   uint32 flags)
 {
 	int natts = relation->rd_att->natts;
-	Bitmapset *attr_needed = NULL;
 
-	attr_needed = bms_add_range(attr_needed, 0, natts - 1);
+	/* attr_needed represents 0-indexed attribute numbers */
+	Bitmapset *attr_needed = bms_add_range(NULL, 0, natts - 1);
 
 	/* the columnar access method does not use the flags, they are specific to heap */
 	flags = 0;
@@ -241,18 +213,14 @@ static ColumnarReadState *
 init_columnar_read_state(Relation relation, TupleDesc tupdesc, Bitmapset *attr_needed,
 						 List *scanQual)
 {
-	List *columnList = RelationColumnList(tupdesc);
-	ListCell *columnCell = NULL;
-
 	List *neededColumnList = NIL;
 
-	/* only collect columns that we need for the scan */
+	for (int i = 0; i < tupdesc->natts; i++)
-	foreach(columnCell, columnList)
 	{
-		Var *var = castNode(Var, lfirst(columnCell));
+		if (bms_is_member(i, attr_needed) && !tupdesc->attrs[i].attisdropped)
-		if (bms_is_member(var->varattno - 1, attr_needed))
 		{
-			neededColumnList = lappend(neededColumnList, var);
+			/* attr_needed is 0-indexed; neededColumnList is 1-indexed */
+			neededColumnList = lappend_int(neededColumnList, i + 1);
 		}
 	}
 
@@ -648,8 +616,18 @@ columnar_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 														columnarOptions,
 														targetDesc);
 
+	List *projectedColumnList = NIL;
+	for (int i = 0; i < sourceDesc->natts; i++)
+	{
+		if (!sourceDesc->attrs[i].attisdropped)
+		{
+			/* projectedColumnList is 1-indexed */
+			projectedColumnList = lappend_int(projectedColumnList, i + 1);
+		}
+	}
+
 	ColumnarReadState *readState = ColumnarBeginRead(OldHeap, sourceDesc,
-													 RelationColumnList(sourceDesc),
+													 projectedColumnList,
 													 NULL);
 
 	Datum *values = palloc0(sourceDesc->natts * sizeof(Datum));