4 files changed, 102 insertions, 0 deletions

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 0fb5d61a3f..fb490b404c 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1982,6 +1982,21 @@ typedef struct MaterialState
 	Tuplestorestate *tuplestorestate;
 } MaterialState;
 
+
+/* ----------------
+ *	 When performing sorting by multiple keys, it's possible that the input
+ *	 dataset is already sorted on a prefix of those keys. We call these
+ *	 "presorted keys".
+ *	 PresortedKeyData represents information about one such key.
+ * ----------------
+ */
+typedef struct PresortedKeyData
+{
+	FmgrInfo	flinfo;			/* comparison function info */
+	FunctionCallInfo fcinfo;	/* comparison function call info */
+	OffsetNumber attno;			/* attribute number in tuple */
+} PresortedKeyData;
+
 /* ----------------
  *	 Shared memory container for per-worker sort information
  * ----------------
@@ -2010,6 +2025,71 @@ typedef struct SortState
 	SharedSortInfo *shared_info;	/* one entry per worker */
 } SortState;
 
+/* ----------------
+ *	 Instrumentation information for IncrementalSort
+ * ----------------
+ */
+typedef struct IncrementalSortGroupInfo
+{
+	int64		groupCount;
+	long		maxDiskSpaceUsed;
+	long		totalDiskSpaceUsed;
+	long		maxMemorySpaceUsed;
+	long		totalMemorySpaceUsed;
+	bits32		sortMethods; /* bitmask of TuplesortMethod */
+} IncrementalSortGroupInfo;
+
+typedef struct IncrementalSortInfo
+{
+	IncrementalSortGroupInfo fullsortGroupInfo;
+	IncrementalSortGroupInfo prefixsortGroupInfo;
+} IncrementalSortInfo;
+
+/* ----------------
+ *	 Shared memory container for per-worker incremental sort information
+ * ----------------
+ */
+typedef struct SharedIncrementalSortInfo
+{
+	int			num_workers;
+	IncrementalSortInfo sinfo[FLEXIBLE_ARRAY_MEMBER];
+} SharedIncrementalSortInfo;
+
+/* ----------------
+ *	 IncrementalSortState information
+ * ----------------
+ */
+typedef enum
+{
+	INCSORT_LOADFULLSORT,
+	INCSORT_LOADPREFIXSORT,
+	INCSORT_READFULLSORT,
+	INCSORT_READPREFIXSORT,
+} IncrementalSortExecutionStatus;
+
+typedef struct IncrementalSortState
+{
+	ScanState	ss;				/* its first field is NodeTag */
+	bool		bounded;		/* is the result set bounded? */
+	int64		bound;			/* if bounded, how many tuples are needed */
+	bool		outerNodeDone;	/* finished fetching tuples from outer node */
+	int64		bound_Done;		/* value of bound we did the sort with */
+	IncrementalSortExecutionStatus execution_status;
+	int64		n_fullsort_remaining;
+	Tuplesortstate *fullsort_state; /* private state of tuplesort.c */
+	Tuplesortstate *prefixsort_state;	/* private state of tuplesort.c */
+	/* the keys by which the input path is already sorted */
+	PresortedKeyData *presorted_keys;
+
+	IncrementalSortInfo incsort_info;
+
+	/* slot for pivot tuple defining values of presorted keys within group */
+	TupleTableSlot *group_pivot;
+	TupleTableSlot *transfer_tuple;
+	bool		am_worker;		/* are we a worker? */
+	SharedIncrementalSortInfo *shared_info; /* one entry per worker */
+} IncrementalSortState;
+
 /* ---------------------
  *	GroupState information
  * ---------------------
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 8a76afe8cc..50b1ba5186 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -74,6 +74,7 @@ typedef enum NodeTag
 	T_HashJoin,
 	T_Material,
 	T_Sort,
+	T_IncrementalSort,
 	T_Group,
 	T_Agg,
 	T_WindowAgg,
@@ -130,6 +131,7 @@ typedef enum NodeTag
 	T_HashJoinState,
 	T_MaterialState,
 	T_SortState,
+	T_IncrementalSortState,
 	T_GroupState,
 	T_AggState,
 	T_WindowAggState,
@@ -245,6 +247,7 @@ typedef enum NodeTag
 	T_ProjectionPath,
 	T_ProjectSetPath,
 	T_SortPath,
+	T_IncrementalSortPath,
 	T_GroupPath,
 	T_UpperUniquePath,
 	T_AggPath,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 469c686e3f..a6d206b25a 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1639,6 +1639,15 @@ typedef struct SortPath
 } SortPath;
 
 /*
+ * IncrementalSortPath
+ */
+typedef struct IncrementalSortPath
+{
+	SortPath	spath;
+	int			nPresortedCols;	/* number of presorted columns */
+} IncrementalSortPath;
+
+/*
  * GroupPath represents grouping (of presorted input)
  *
  * groupClause represents the columns to be grouped on; the input path
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 4869fe7b6d..be8ef54a1e 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -774,6 +774,16 @@ typedef struct Sort
 	bool	   *nullsFirst;		/* NULLS FIRST/LAST directions */
 } Sort;
 
+/* ----------------
+ *		incremental sort node
+ * ----------------
+ */
+typedef struct IncrementalSort
+{
+	Sort		sort;
+	int			nPresortedCols;	/* number of presorted columns */
+} IncrementalSort;
+
 /* ---------------
  *	 group node -
  *		Used for queries with GROUP BY (but no aggregates) specified.