Use more efficient hashtable for execGrouping.c to speed up hash aggregation.faster-hashtable

The more efficient hashtable speeds up hash-aggregations with more than
a few hundred groups significantly. Improvements of over 120% have been
measured.

Due to the the different hash table queries that not fully
determined (e.g. GROUP BY without ORDER BY) may change their result
order.

The conversion is largely straight-forward, except that, due to the
static element types of simplehash.h type hashes, the additional data
some users store in elements (e.g. the per-group working data for hash
aggregaters) is now stored in TupleHashEntryData->additional.  The
meaning of BuildTupleHashTable's entrysize (renamed to additionalsize)
has been changed to only be about the additionally stored size.  That
size is only used for the initial sizing of the hash-table.

TODO:
* Should hash agg size estimation for the planner consider the
  fillfactor?

13 files changed, 144 insertions, 204 deletions

diff --git a/src/backend/executor/execGrouping.c b/src/backend/executor/execGrouping.c
index 808275a094..f80da1943a 100644
--- a/src/backend/executor/execGrouping.c
+++ b/src/backend/executor/execGrouping.c
@@ -23,12 +23,25 @@
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 
+static uint32 TupleHashTableHash(struct tuplehash_hash *tb, const MinimalTuple tuple);
+static int TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2);
 
-static TupleHashTable CurTupleHashTable = NULL;
-
-static uint32 TupleHashTableHash(const void *key, Size keysize);
-static int TupleHashTableMatch(const void *key1, const void *key2,
-					Size keysize);
+/*
+ * Define parameters for tuple hash table code generation. The interface is
+ * *also* declared in execnodes.h (to generate the types, which are externally
+ * visible).
+ */
+#define SH_PREFIX tuplehash
+#define SH_KEYTYPE MinimalTuple
+#define SH_KEY firstTuple
+#define SH_CONTAINS TupleHashEntryData
+#define SH_HASH_KEY(tb, key) TupleHashTableHash(tb, key)
+#define SH_EQUAL(tb, a, b) TupleHashTableMatch(tb, a, b) == 0
+#define SH_SCOPE extern
+#define SH_STORE_HASH
+#define SH_GET_HASH(tb, a) a->hash
+#define SH_DEFINE
+#include "lib/simplehash.h"
 
 
 /*****************************************************************************
@@ -260,7 +273,7 @@ execTuplesHashPrepare(int numCols,
  *	eqfunctions: equality comparison functions to use
  *	hashfunctions: datatype-specific hashing functions to use
  *	nbuckets: initial estimate of hashtable size
- *	entrysize: size of each entry (at least sizeof(TupleHashEntryData))
+ *	additionalsize: size of data stored in ->additional
  *	tablecxt: memory context in which to store table and table entries
  *	tempcxt: short-lived context for evaluation hash and comparison functions
  *
@@ -275,20 +288,18 @@ TupleHashTable
 BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
 					FmgrInfo *eqfunctions,
 					FmgrInfo *hashfunctions,
-					long nbuckets, Size entrysize,
+					long nbuckets, Size additionalsize,
 					MemoryContext tablecxt, MemoryContext tempcxt)
 {
 	TupleHashTable hashtable;
-	HASHCTL		hash_ctl;
-
+	Size		entrysize = sizeof(TupleHashEntryData) + additionalsize;
 	Assert(nbuckets > 0);
-	Assert(entrysize >= sizeof(TupleHashEntryData));
 
 	/* Limit initial table size request to not more than work_mem */
 	nbuckets = Min(nbuckets, (long) ((work_mem * 1024L) / entrysize));
 
-	hashtable = (TupleHashTable) MemoryContextAlloc(tablecxt,
-												 sizeof(TupleHashTableData));
+	hashtable = (TupleHashTable)
+		MemoryContextAlloc(tablecxt, sizeof(TupleHashTableData));
 
 	hashtable->numCols = numCols;
 	hashtable->keyColIdx = keyColIdx;
@@ -302,15 +313,8 @@ BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
 	hashtable->in_hash_funcs = NULL;
 	hashtable->cur_eq_funcs = NULL;
 
-	MemSet(&hash_ctl, 0, sizeof(hash_ctl));
-	hash_ctl.keysize = sizeof(TupleHashEntryData);
-	hash_ctl.entrysize = entrysize;
-	hash_ctl.hash = TupleHashTableHash;
-	hash_ctl.match = TupleHashTableMatch;
-	hash_ctl.hcxt = tablecxt;
-	hashtable->hashtab = hash_create("TupleHashTable", nbuckets,
-									 &hash_ctl,
-					HASH_ELEM | HASH_FUNCTION | HASH_COMPARE | HASH_CONTEXT);
+	hashtable->hashtab = tuplehash_create(tablecxt, nbuckets);
+	hashtable->hashtab->private = hashtable;
 
 	return hashtable;
 }
@@ -324,18 +328,17 @@ BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
  *
  * If isnew isn't NULL, then a new entry is created if no existing entry
  * matches.  On return, *isnew is true if the entry is newly created,
- * false if it existed already.  Any extra space in a new entry has been
- * zeroed.
+ * false if it existed already.  ->additional_data in the new entry has
+ * been zeroed.
  */
 TupleHashEntry
 LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
 					 bool *isnew)
 {
-	TupleHashEntry entry;
+	TupleHashEntryData *entry;
 	MemoryContext oldContext;
-	TupleHashTable saveCurHT;
-	TupleHashEntryData dummy;
 	bool		found;
+	MinimalTuple key;
 
 	/* If first time through, clone the input slot to make table slot */
 	if (hashtable->tableslot == NULL)
@@ -358,26 +361,17 @@ LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
 
 	/*
 	 * Set up data needed by hash and match functions
-	 *
-	 * We save and restore CurTupleHashTable just in case someone manages to
-	 * invoke this code re-entrantly.
 	 */
 	hashtable->inputslot = slot;
 	hashtable->in_hash_funcs = hashtable->tab_hash_funcs;
 	hashtable->cur_eq_funcs = hashtable->tab_eq_funcs;
 
-	saveCurHT = CurTupleHashTable;
-	CurTupleHashTable = hashtable;
-
-	/* Search the hash table */
-	dummy.firstTuple = NULL;	/* flag to reference inputslot */
-	entry = (TupleHashEntry) hash_search(hashtable->hashtab,
-										 &dummy,
-										 isnew ? HASH_ENTER : HASH_FIND,
-										 &found);
+	key = NULL;
 
 	if (isnew)
 	{
+		entry = tuplehash_insert(hashtable->hashtab, key, &found);
+
 		if (found)
 		{
 			/* found pre-existing entry */
@@ -385,24 +379,20 @@ LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
 		}
 		else
 		{
-			/*
-			 * created new entry
-			 *
-			 * Zero any caller-requested space in the entry.  (This zaps the
-			 * "key data" dynahash.c copied into the new entry, but we don't
-			 * care since we're about to overwrite it anyway.)
-			 */
-			MemSet(entry, 0, hashtable->entrysize);
-
-			/* Copy the first tuple into the table context */
+			/* created new entry */
+			*isnew = true;
+			/* zero caller data */
+			entry->additional = NULL;
 			MemoryContextSwitchTo(hashtable->tablecxt);
+			/* Copy the first tuple into the table context */
 			entry->firstTuple = ExecCopySlotMinimalTuple(slot);
-
-			*isnew = true;
 		}
 	}
+	else
+	{
+		entry = tuplehash_lookup(hashtable->hashtab, key);
+	}
 
-	CurTupleHashTable = saveCurHT;
 
 	MemoryContextSwitchTo(oldContext);
 
@@ -425,34 +415,19 @@ FindTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
 {
 	TupleHashEntry entry;
 	MemoryContext oldContext;
-	TupleHashTable saveCurHT;
-	TupleHashEntryData dummy;
+	MinimalTuple key;
 
 	/* Need to run the hash functions in short-lived context */
 	oldContext = MemoryContextSwitchTo(hashtable->tempcxt);
 
-	/*
-	 * Set up data needed by hash and match functions
-	 *
-	 * We save and restore CurTupleHashTable just in case someone manages to
-	 * invoke this code re-entrantly.
-	 */
+	/* Set up data needed by hash and match functions */
 	hashtable->inputslot = slot;
 	hashtable->in_hash_funcs = hashfunctions;
 	hashtable->cur_eq_funcs = eqfunctions;
 
-	saveCurHT = CurTupleHashTable;
-	CurTupleHashTable = hashtable;
-
 	/* Search the hash table */
-	dummy.firstTuple = NULL;	/* flag to reference inputslot */
-	entry = (TupleHashEntry) hash_search(hashtable->hashtab,
-										 &dummy,
-										 HASH_FIND,
-										 NULL);
-
-	CurTupleHashTable = saveCurHT;
-
+	key = NULL;	/* flag to reference inputslot */
+	entry = tuplehash_lookup(hashtable->hashtab, key);
 	MemoryContextSwitchTo(oldContext);
 
 	return entry;
@@ -468,22 +443,18 @@ FindTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
  * This convention avoids the need to materialize virtual input tuples unless
  * they actually need to get copied into the table.
  *
- * CurTupleHashTable must be set before calling this, since dynahash.c
- * doesn't provide any API that would let us get at the hashtable otherwise.
- *
  * Also, the caller must select an appropriate memory context for running
  * the hash functions. (dynahash.c doesn't change CurrentMemoryContext.)
  */
 static uint32
-TupleHashTableHash(const void *key, Size keysize)
+TupleHashTableHash(struct tuplehash_hash *tb, const MinimalTuple tuple)
 {
-	MinimalTuple tuple = ((const TupleHashEntryData *) key)->firstTuple;
-	TupleTableSlot *slot;
-	TupleHashTable hashtable = CurTupleHashTable;
+	TupleHashTable hashtable = (TupleHashTable) tb->private;
 	int			numCols = hashtable->numCols;
 	AttrNumber *keyColIdx = hashtable->keyColIdx;
-	FmgrInfo   *hashfunctions;
 	uint32		hashkey = 0;
+	TupleTableSlot *slot;
+	FmgrInfo   *hashfunctions;
 	int			i;
 
 	if (tuple == NULL)
@@ -495,7 +466,6 @@ TupleHashTableHash(const void *key, Size keysize)
 	else
 	{
 		/* Process a tuple already stored in the table */
-		/* (this case never actually occurs in current dynahash.c code) */
 		slot = hashtable->tableslot;
 		ExecStoreMinimalTuple(tuple, slot, false);
 		hashfunctions = hashtable->tab_hash_funcs;
@@ -530,30 +500,23 @@ TupleHashTableHash(const void *key, Size keysize)
  *
  * As above, the passed pointers are pointers to TupleHashEntryData.
  *
- * CurTupleHashTable must be set before calling this, since dynahash.c
- * doesn't provide any API that would let us get at the hashtable otherwise.
- *
  * Also, the caller must select an appropriate memory context for running
  * the compare functions.  (dynahash.c doesn't change CurrentMemoryContext.)
  */
 static int
-TupleHashTableMatch(const void *key1, const void *key2, Size keysize)
+TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2)
 {
-	MinimalTuple tuple1 = ((const TupleHashEntryData *) key1)->firstTuple;
-
-#ifdef USE_ASSERT_CHECKING
-	MinimalTuple tuple2 = ((const TupleHashEntryData *) key2)->firstTuple;
-#endif
 	TupleTableSlot *slot1;
 	TupleTableSlot *slot2;
-	TupleHashTable hashtable = CurTupleHashTable;
+	TupleHashTable hashtable = (TupleHashTable) tb->private;
 
 	/*
-	 * We assume that dynahash.c will only ever call us with the first
+	 * We assume that simplehash.h will only ever call us with the first
 	 * argument being an actual table entry, and the second argument being
 	 * LookupTupleHashEntry's dummy TupleHashEntryData.  The other direction
-	 * could be supported too, but is not currently used by dynahash.c.
+	 * could be supported too, but is not currently required..
 	 */
+
 	Assert(tuple1 != NULL);
 	slot1 = hashtable->tableslot;
 	ExecStoreMinimalTuple(tuple1, slot1, false);
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index ce2fc281a4..ec1c72e9bb 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -434,20 +434,6 @@ typedef struct AggStatePerPhaseData
 	Sort	   *sortnode;		/* Sort node for input ordering for phase */
 }	AggStatePerPhaseData;
 
-/*
- * To implement hashed aggregation, we need a hashtable that stores a
- * representative tuple and an array of AggStatePerGroup structs for each
- * distinct set of GROUP BY column values.  We compute the hash key from
- * the GROUP BY columns.
- */
-typedef struct AggHashEntryData *AggHashEntry;
-
-typedef struct AggHashEntryData
-{
-	TupleHashEntryData shared;	/* common header for hash table entries */
-	/* per-aggregate transition status array */
-	AggStatePerGroupData pergroup[FLEXIBLE_ARRAY_MEMBER];
-}	AggHashEntryData;
 
 static void initialize_phase(AggState *aggstate, int newphase);
 static TupleTableSlot *fetch_input_tuple(AggState *aggstate);
@@ -487,7 +473,7 @@ static TupleTableSlot *project_aggregates(AggState *aggstate);
 static Bitmapset *find_unaggregated_cols(AggState *aggstate);
 static bool find_unaggregated_cols_walker(Node *node, Bitmapset **colnos);
 static void build_hash_table(AggState *aggstate);
-static AggHashEntry lookup_hash_entry(AggState *aggstate,
+static TupleHashEntryData *lookup_hash_entry(AggState *aggstate,
 				  TupleTableSlot *inputslot);
 static TupleTableSlot *agg_retrieve_direct(AggState *aggstate);
 static void agg_fill_hash_table(AggState *aggstate);
@@ -1653,20 +1639,19 @@ build_hash_table(AggState *aggstate)
 {
 	Agg		   *node = (Agg *) aggstate->ss.ps.plan;
 	MemoryContext tmpmem = aggstate->tmpcontext->ecxt_per_tuple_memory;
-	Size		entrysize;
+	Size		additionalsize;
 
 	Assert(node->aggstrategy == AGG_HASHED);
 	Assert(node->numGroups > 0);
 
-	entrysize = offsetof(AggHashEntryData, pergroup) +
-		aggstate->numaggs * sizeof(AggStatePerGroupData);
+	additionalsize = aggstate->numaggs * sizeof(AggStatePerGroupData);
 
 	aggstate->hashtable = BuildTupleHashTable(node->numCols,
 											  node->grpColIdx,
 											  aggstate->phase->eqfunctions,
 											  aggstate->hashfunctions,
 											  node->numGroups,
-											  entrysize,
+											  additionalsize,
 							 aggstate->aggcontexts[0]->ecxt_per_tuple_memory,
 											  tmpmem);
 }
@@ -1730,11 +1715,10 @@ hash_agg_entry_size(int numAggs)
 	Size		entrysize;
 
 	/* This must match build_hash_table */
-	entrysize = offsetof(AggHashEntryData, pergroup) +
+	entrysize = sizeof(TupleHashEntryData) +
 		numAggs * sizeof(AggStatePerGroupData);
 	entrysize = MAXALIGN(entrysize);
-	/* Account for hashtable overhead (assuming fill factor = 1) */
-	entrysize += 3 * sizeof(void *);
+	/* FIXME: Do we want to handle fill factor overhead here? */
 	return entrysize;
 }
 
@@ -1744,18 +1728,21 @@ hash_agg_entry_size(int numAggs)
  *
  * When called, CurrentMemoryContext should be the per-query context.
  */
-static AggHashEntry
+static TupleHashEntryData *
 lookup_hash_entry(AggState *aggstate, TupleTableSlot *inputslot)
 {
 	TupleTableSlot *hashslot = aggstate->hashslot;
 	ListCell   *l;
-	AggHashEntry entry;
+	TupleHashEntryData *entry;
 	bool		isnew;
 
 	/* if first time through, initialize hashslot by cloning input slot */
 	if (hashslot->tts_tupleDescriptor == NULL)
 	{
-		ExecSetSlotDescriptor(hashslot, inputslot->tts_tupleDescriptor);
+		MemoryContext oldContext = MemoryContextSwitchTo(hashslot->tts_mcxt);
+		/* get rid of constraints */
+		ExecSetSlotDescriptor(hashslot, CreateTupleDescCopy(inputslot->tts_tupleDescriptor));
+		MemoryContextSwitchTo(oldContext);
 		/* Make sure all unused columns are NULLs */
 		ExecStoreAllNullTuple(hashslot);
 	}
@@ -1771,14 +1758,14 @@ lookup_hash_entry(AggState *aggstate, TupleTableSlot *inputslot)
 	}
 
 	/* find or create the hashtable entry using the filtered tuple */
-	entry = (AggHashEntry) LookupTupleHashEntry(aggstate->hashtable,
-												hashslot,
-												&isnew);
+	entry = LookupTupleHashEntry(aggstate->hashtable, hashslot, &isnew);
 
 	if (isnew)
 	{
+		entry->additional = MemoryContextAlloc(aggstate->hashtable->tablecxt,
+											   sizeof(AggStatePerGroupData) * aggstate->numtrans);
 		/* initialize aggregates for new tuple group */
-		initialize_aggregates(aggstate, entry->pergroup, 0);
+		initialize_aggregates(aggstate, entry->additional, 0);
 	}
 
 	return entry;
@@ -2176,7 +2163,7 @@ static void
 agg_fill_hash_table(AggState *aggstate)
 {
 	ExprContext *tmpcontext;
-	AggHashEntry entry;
+	TupleHashEntryData *entry;
 	TupleTableSlot *outerslot;
 
 	/*
@@ -2203,9 +2190,9 @@ agg_fill_hash_table(AggState *aggstate)
 
 		/* Advance the aggregates */
 		if (DO_AGGSPLIT_COMBINE(aggstate->aggsplit))
-			combine_aggregates(aggstate, entry->pergroup);
+			combine_aggregates(aggstate, entry->additional);
 		else
-			advance_aggregates(aggstate, entry->pergroup);
+			advance_aggregates(aggstate, entry->additional);
 
 		/* Reset per-input-tuple context after each tuple */
 		ResetExprContext(tmpcontext);
@@ -2225,7 +2212,7 @@ agg_retrieve_hash_table(AggState *aggstate)
 	ExprContext *econtext;
 	AggStatePerAgg peragg;
 	AggStatePerGroup pergroup;
-	AggHashEntry entry;
+	TupleHashEntryData *entry;
 	TupleTableSlot *firstSlot;
 	TupleTableSlot *result;
 
@@ -2246,7 +2233,7 @@ agg_retrieve_hash_table(AggState *aggstate)
 		/*
 		 * Find the next entry in the hash table
 		 */
-		entry = (AggHashEntry) ScanTupleHashTable(&aggstate->hashiter);
+		entry = ScanTupleHashTable(aggstate->hashtable, &aggstate->hashiter);
 		if (entry == NULL)
 		{
 			/* No more entries in hashtable, so done */
@@ -2267,11 +2254,11 @@ agg_retrieve_hash_table(AggState *aggstate)
 		 * Store the copied first input tuple in the tuple table slot reserved
 		 * for it, so that it can be used in ExecProject.
 		 */
-		ExecStoreMinimalTuple(entry->shared.firstTuple,
+		ExecStoreMinimalTuple(entry->firstTuple,
 							  firstSlot,
 							  false);
 
-		pergroup = entry->pergroup;
+		pergroup = entry->additional;
 
 		finalize_aggregates(aggstate, peragg, pergroup, 0);
 
diff --git a/src/backend/executor/nodeRecursiveunion.c b/src/backend/executor/nodeRecursiveunion.c
index 39be191c45..6e7d9d2731 100644
--- a/src/backend/executor/nodeRecursiveunion.c
+++ b/src/backend/executor/nodeRecursiveunion.c
@@ -20,17 +20,6 @@
 #include "utils/memutils.h"
 
 
-/*
- * To implement UNION (without ALL), we need a hashtable that stores tuples
- * already seen.  The hash key is computed from the grouping columns.
- */
-typedef struct RUHashEntryData *RUHashEntry;
-
-typedef struct RUHashEntryData
-{
-	TupleHashEntryData shared;	/* common header for hash table entries */
-}	RUHashEntryData;
-
 
 /*
  * Initialize the hash table to empty.
@@ -48,7 +37,7 @@ build_hash_table(RecursiveUnionState *rustate)
 											 rustate->eqfunctions,
 											 rustate->hashfunctions,
 											 node->numGroups,
-											 sizeof(RUHashEntryData),
+											 0,
 											 rustate->tableContext,
 											 rustate->tempContext);
 }
diff --git a/src/backend/executor/nodeSetOp.c b/src/backend/executor/nodeSetOp.c
index 633580b436..37d0477d1d 100644
--- a/src/backend/executor/nodeSetOp.c
+++ b/src/backend/executor/nodeSetOp.c
@@ -66,19 +66,6 @@ typedef struct SetOpStatePerGroupData
 	long		numRight;		/* number of right-input dups in group */
 } SetOpStatePerGroupData;
 
-/*
- * To implement hashed mode, we need a hashtable that stores a
- * representative tuple and the duplicate counts for each distinct set
- * of grouping columns.  We compute the hash key from the grouping columns.
- */
-typedef struct SetOpHashEntryData *SetOpHashEntry;
-
-typedef struct SetOpHashEntryData
-{
-	TupleHashEntryData shared;	/* common header for hash table entries */
-	SetOpStatePerGroupData pergroup;
-}	SetOpHashEntryData;
-
 
 static TupleTableSlot *setop_retrieve_direct(SetOpState *setopstate);
 static void setop_fill_hash_table(SetOpState *setopstate);
@@ -141,7 +128,7 @@ build_hash_table(SetOpState *setopstate)
 												setopstate->eqfunctions,
 												setopstate->hashfunctions,
 												node->numGroups,
-												sizeof(SetOpHashEntryData),
+												0,
 												setopstate->tableContext,
 												setopstate->tempContext);
 }
@@ -367,7 +354,7 @@ setop_fill_hash_table(SetOpState *setopstate)
 	{
 		TupleTableSlot *outerslot;
 		int			flag;
-		SetOpHashEntry entry;
+		TupleHashEntryData *entry;
 		bool		isnew;
 
 		outerslot = ExecProcNode(outerPlan);
@@ -383,15 +370,19 @@ setop_fill_hash_table(SetOpState *setopstate)
 			Assert(in_first_rel);
 
 			/* Find or build hashtable entry for this tuple's group */
-			entry = (SetOpHashEntry)
-				LookupTupleHashEntry(setopstate->hashtable, outerslot, &isnew);
+			entry = LookupTupleHashEntry(setopstate->hashtable, outerslot,
+										 &isnew);
 
 			/* If new tuple group, initialize counts */
 			if (isnew)
-				initialize_counts(&entry->pergroup);
+			{
+				entry->additional = MemoryContextAlloc(setopstate->hashtable->tablecxt,
+													   sizeof(SetOpStatePerGroupData));
+				initialize_counts(entry->additional);
+			}
 
 			/* Advance the counts */
-			advance_counts(&entry->pergroup, flag);
+			advance_counts(entry->additional, flag);
 		}
 		else
 		{
@@ -399,12 +390,12 @@ setop_fill_hash_table(SetOpState *setopstate)
 			in_first_rel = false;
 
 			/* For tuples not seen previously, do not make hashtable entry */
-			entry = (SetOpHashEntry)
-				LookupTupleHashEntry(setopstate->hashtable, outerslot, NULL);
+			entry = LookupTupleHashEntry(setopstate->hashtable, outerslot,
+										 NULL);
 
 			/* Advance the counts if entry is already present */
 			if (entry)
-				advance_counts(&entry->pergroup, flag);
+				advance_counts(entry->additional, flag);
 		}
 
 		/* Must reset temp context after each hashtable lookup */
@@ -422,7 +413,7 @@ setop_fill_hash_table(SetOpState *setopstate)
 static TupleTableSlot *
 setop_retrieve_hash_table(SetOpState *setopstate)
 {
-	SetOpHashEntry entry;
+	TupleHashEntryData *entry;
 	TupleTableSlot *resultTupleSlot;
 
 	/*
@@ -438,7 +429,7 @@ setop_retrieve_hash_table(SetOpState *setopstate)
 		/*
 		 * Find the next entry in the hash table
 		 */
-		entry = (SetOpHashEntry) ScanTupleHashTable(&setopstate->hashiter);
+		entry = ScanTupleHashTable(setopstate->hashtable, &setopstate->hashiter);
 		if (entry == NULL)
 		{
 			/* No more entries in hashtable, so done */
@@ -450,12 +441,12 @@ setop_retrieve_hash_table(SetOpState *setopstate)
 		 * See if we should emit any copies of this tuple, and if so return
 		 * the first copy.
 		 */
-		set_output_count(setopstate, &entry->pergroup);
+		set_output_count(setopstate, entry->additional);
 
 		if (setopstate->numOutput > 0)
 		{
 			setopstate->numOutput--;
-			return ExecStoreMinimalTuple(entry->shared.firstTuple,
+			return ExecStoreMinimalTuple(entry->firstTuple,
 										 resultTupleSlot,
 										 false);
 		}
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 2cf169f956..8ca8fc460c 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -508,7 +508,7 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
 										  node->tab_eq_funcs,
 										  node->tab_hash_funcs,
 										  nbuckets,
-										  sizeof(TupleHashEntryData),
+										  0,
 										  node->hashtablecxt,
 										  node->hashtempcxt);
 
@@ -527,7 +527,7 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
 											  node->tab_eq_funcs,
 											  node->tab_hash_funcs,
 											  nbuckets,
-											  sizeof(TupleHashEntryData),
+											  0,
 											  node->hashtablecxt,
 											  node->hashtempcxt);
 	}
@@ -626,7 +626,7 @@ findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot,
 	TupleHashEntry entry;
 
 	InitTupleHashIterator(hashtable, &hashiter);
-	while ((entry = ScanTupleHashTable(&hashiter)) != NULL)
+	while ((entry = ScanTupleHashTable(hashtable, &hashiter)) != NULL)
 	{
 		ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false);
 		if (!execTuplesUnequal(slot, hashtable->tableslot,
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 39521ed08e..136276be53 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -140,7 +140,7 @@ extern void execTuplesHashPrepare(int numCols,
 extern TupleHashTable BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
 					FmgrInfo *eqfunctions,
 					FmgrInfo *hashfunctions,
-					long nbuckets, Size entrysize,
+					long nbuckets, Size additionalsize,
 					MemoryContext tablecxt,
 					MemoryContext tempcxt);
 extern TupleHashEntry LookupTupleHashEntry(TupleHashTable hashtable,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 4fa366178f..3148f3a86b 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -499,14 +499,29 @@ typedef struct TupleHashTableData *TupleHashTable;
 
 typedef struct TupleHashEntryData
 {
-	/* firstTuple must be the first field in this struct! */
 	MinimalTuple firstTuple;	/* copy of first tuple in this group */
-	/* there may be additional data beyond the end of this struct */
-} TupleHashEntryData;			/* VARIABLE LENGTH STRUCT */
+	void		*additional;	/* user data */
+	uint32		status;			/* hash status */
+	uint32		hash;			/* hash value (cached) */
+} TupleHashEntryData;
+
+/*
+ * Define paramters necessary to generate the tuple hash table interface
+ * functions.
+ */
+#define SH_PREFIX tuplehash
+#define SH_KEYTYPE MinimalTuple
+#define SH_KEY key
+#define SH_CONTAINS TupleHashEntryData
+#define SH_SCOPE extern
+#define SH_DECLARE
+#include "lib/simplehash.h"
+
+typedef tuplehash_iterator TupleHashIterator;
 
 typedef struct TupleHashTableData
 {
-	HTAB	   *hashtab;		/* underlying dynahash table */
+	struct tuplehash_hash *hashtab;	/* underlying hash table */
 	int			numCols;		/* number of columns in lookup key */
 	AttrNumber *keyColIdx;		/* attr numbers of key columns */
 	FmgrInfo   *tab_hash_funcs; /* hash functions for table datatype(s) */
@@ -521,24 +536,19 @@ typedef struct TupleHashTableData
 	FmgrInfo   *cur_eq_funcs;	/* equality functions for input vs. table */
 }	TupleHashTableData;
 
-typedef HASH_SEQ_STATUS TupleHashIterator;
-
 /*
  * Use InitTupleHashIterator/TermTupleHashIterator for a read/write scan.
  * Use ResetTupleHashIterator if the table can be frozen (in this case no
  * explicit scan termination is needed).
  */
 #define InitTupleHashIterator(htable, iter) \
-	hash_seq_init(iter, (htable)->hashtab)
+	tuplehash_start_iterate(htable->hashtab, iter)
 #define TermTupleHashIterator(iter) \
-	hash_seq_term(iter)
+	(void)0
 #define ResetTupleHashIterator(htable, iter) \
-	do { \
-		hash_freeze((htable)->hashtab); \
-		hash_seq_init(iter, (htable)->hashtab); \
-	} while (0)
-#define ScanTupleHashTable(iter) \
-	((TupleHashEntry) hash_seq_search(iter))
+	InitTupleHashIterator(htable, iter)
+#define ScanTupleHashTable(htable, iter) \
+	tuplehash_iterate(htable->hashtab, iter)
 
 
 /* ----------------------------------------------------------------
diff --git a/src/test/regress/expected/matview.out b/src/test/regress/expected/matview.out
index e7d0ad1d86..8668b77e9c 100644
--- a/src/test/regress/expected/matview.out
+++ b/src/test/regress/expected/matview.out
@@ -47,9 +47,9 @@ CREATE UNIQUE INDEX mvtest_tm_type ON mvtest_tm (type);
 SELECT * FROM mvtest_tm;
  type | totamt 
 ------+--------
- y    |     12
- z    |     11
  x    |      5
+ z    |     11
+ y    |     12
 (3 rows)
 
 -- create various views
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 017b79ea9c..464436ab3b 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -123,7 +123,7 @@ unicode_header_linestyle single
 prepare q as select array_to_string(array_agg(repeat('x',2*n)),E'\n') as "ab
 
 c", array_to_string(array_agg(repeat('y',20-2*n)),E'\n') as "a
-bc" from generate_series(1,10) as n(n) group by n>1 ;
+bc" from generate_series(1,10) as n(n) group by n>1 order by n>1;
 \pset linestyle ascii
 \pset expanded off
 \pset columns 40
diff --git a/src/test/regress/expected/tsrf.out b/src/test/regress/expected/tsrf.out
index d9a5f137dc..07db3a1fc7 100644
--- a/src/test/regress/expected/tsrf.out
+++ b/src/test/regress/expected/tsrf.out
@@ -190,12 +190,12 @@ SELECT SUM(count(*)) OVER(PARTITION BY generate_series(1,3) ORDER BY generate_se
 SELECT few.dataa, count(*), min(id), max(id), generate_series(1,3) FROM few GROUP BY few.dataa ORDER BY 5;
  dataa | count | min | max | generate_series 
 -------+-------+-----+-----+-----------------
- b     |     1 |   3 |   3 |               1
  a     |     2 |   1 |   2 |               1
- b     |     1 |   3 |   3 |               2
+ b     |     1 |   3 |   3 |               1
  a     |     2 |   1 |   2 |               2
- b     |     1 |   3 |   3 |               3
+ b     |     1 |   3 |   3 |               2
  a     |     2 |   1 |   2 |               3
+ b     |     1 |   3 |   3 |               3
 (6 rows)
 
 -- grouping sets are a bit special, they produce NULLs in columns not actually NULL
diff --git a/src/test/regress/expected/union.out b/src/test/regress/expected/union.out
index 016571bd4a..cd8262c53b 100644
--- a/src/test/regress/expected/union.out
+++ b/src/test/regress/expected/union.out
@@ -32,16 +32,16 @@ SELECT 1 AS two UNION ALL SELECT 1;
 SELECT 1 AS three UNION SELECT 2 UNION SELECT 3;
  three 
 -------
-     1
      2
+     1
      3
 (3 rows)
 
 SELECT 1 AS two UNION SELECT 2 UNION SELECT 2;
  two 
 -----
-   1
    2
+   1
 (2 rows)
 
 SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2;
@@ -97,9 +97,9 @@ SELECT 1.0::float8 AS two UNION ALL SELECT 1;
 SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3;
  three 
 -------
-   1.1
-     2
      3
+     2
+   1.1
 (3 rows)
 
 SELECT 1.1::float8 AS two UNION SELECT 2 UNION SELECT 2.0::float8 ORDER BY 1;
@@ -120,8 +120,8 @@ SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2;
 SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2);
  two 
 -----
- 1.1
    2
+ 1.1
 (2 rows)
 
 --
@@ -263,16 +263,16 @@ ORDER BY 1;
 SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl;
         q2        
 ------------------
- 4567890123456789
               123
+ 4567890123456789
 (2 rows)
 
 SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl;
         q2        
 ------------------
+              123
  4567890123456789
  4567890123456789
-              123
 (3 rows)
 
 SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
@@ -305,16 +305,16 @@ SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl;
 SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q2 FROM int8_tbl;
         q1        
 ------------------
- 4567890123456789
               123
+ 4567890123456789
 (2 rows)
 
 SELECT q1 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q2 FROM int8_tbl;
         q1        
 ------------------
+              123
  4567890123456789
  4567890123456789
-              123
 (3 rows)
 
 SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl FOR NO KEY UPDATE;
@@ -343,8 +343,8 @@ SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl ORDER BY 1;
 SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl;
         q1         
 -------------------
-  4567890123456789
                123
+  4567890123456789
                456
   4567890123456789
                123
@@ -355,15 +355,15 @@ SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FR
 SELECT q1 FROM int8_tbl INTERSECT (((SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl)));
         q1        
 ------------------
- 4567890123456789
               123
+ 4567890123456789
 (2 rows)
 
 (((SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl))) UNION ALL SELECT q2 FROM int8_tbl;
         q1         
 -------------------
-  4567890123456789
                123
+  4567890123456789
                456
   4567890123456789
                123
@@ -419,8 +419,8 @@ HINT:  There is a column named "q2" in table "*SELECT* 2", but it cannot be refe
 SELECT q1 FROM int8_tbl EXCEPT (((SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1)));
         q1        
 ------------------
- 4567890123456789
               123
+ 4567890123456789
 (2 rows)
 
 --
diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out
index 137420d9b7..31723be6f1 100644
--- a/src/test/regress/expected/with.out
+++ b/src/test/regress/expected/with.out
@@ -1247,8 +1247,8 @@ WITH outermost(x) AS (
 SELECT * FROM outermost;
  x 
 ---
- 1
  2
+ 1
  3
 (3 rows)
 
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 4dc0745f1d..900aa7ee1e 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -67,7 +67,7 @@ select 'drop table gexec_test', 'select ''2000-01-01''::date as party_over'
 prepare q as select array_to_string(array_agg(repeat('x',2*n)),E'\n') as "ab
 
 c", array_to_string(array_agg(repeat('y',20-2*n)),E'\n') as "a
-bc" from generate_series(1,10) as n(n) group by n>1 ;
+bc" from generate_series(1,10) as n(n) group by n>1 order by n>1;
 
 \pset linestyle ascii