Implement operator class parameters

PostgreSQL provides set of template index access methods, where opclasses have
much freedom in the semantics of indexing.  These index AMs are GiST, GIN,
SP-GiST and BRIN.  There opclasses define representation of keys, operations on
them and supported search strategies.  So, it's natural that opclasses may be
faced some tradeoffs, which require user-side decision.  This commit implements
opclass parameters allowing users to set some values, which tell opclass how to
index the particular dataset.

This commit doesn't introduce new storage in system catalog.  Instead it uses
pg_attribute.attoptions, which is used for table column storage options but
unused for index attributes.

In order to evade changing signature of each opclass support function, we
implement unified way to pass options to opclass support functions.  Options
are set to fn_expr as the constant bytea expression.  It's possible due to the
fact that opclass support functions are executed outside of expressions, so
fn_expr is unused for them.

This commit comes with some examples of opclass options usage.  We parametrize
signature length in GiST.  That applies to multiple opclasses: tsvector_ops,
gist__intbig_ops, gist_ltree_ops, gist__ltree_ops, gist_trgm_ops and
gist_hstore_ops.  Also we parametrize maximum number of integer ranges for
gist__int_ops.  However, the main future usage of this feature is expected
to be json, where users would be able to specify which way to index particular
json parts.

Catversion is bumped.

Discussion: https://postgr.es/m/d22c3a18-31c7-1879-fc11-4c1ce2f5e5af%40postgrespro.ru
Author: Nikita Glukhov, revised by me
Reviwed-by: Nikolay Shaplov, Robert Haas, Tom Lane, Tomas Vondra, Alvaro Herrera

1 files changed, 98 insertions, 91 deletions

diff --git a/contrib/intarray/_intbig_gist.c b/contrib/intarray/_intbig_gist.c
index be51dac1fa7..67c44e99a9a 100644
--- a/contrib/intarray/_intbig_gist.c
+++ b/contrib/intarray/_intbig_gist.c
@@ -5,6 +5,7 @@
 
 #include "_int.h"
 #include "access/gist.h"
+#include "access/reloptions.h"
 #include "access/stratnum.h"
 #include "port/pg_bitutils.h"
 
@@ -19,6 +20,8 @@ PG_FUNCTION_INFO_V1(g_intbig_penalty);
 PG_FUNCTION_INFO_V1(g_intbig_picksplit);
 PG_FUNCTION_INFO_V1(g_intbig_union);
 PG_FUNCTION_INFO_V1(g_intbig_same);
+PG_FUNCTION_INFO_V1(g_intbig_options);
+
 PG_FUNCTION_INFO_V1(_intbig_in);
 PG_FUNCTION_INFO_V1(_intbig_out);
 
@@ -40,12 +43,33 @@ _intbig_out(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(0);
 }
 
+static GISTTYPE *
+_intbig_alloc(bool allistrue, int siglen, BITVECP sign)
+{
+	int			flag = allistrue ? ALLISTRUE : 0;
+	int			size = CALCGTSIZE(flag, siglen);
+	GISTTYPE   *res = (GISTTYPE *) palloc(size);
+
+	SET_VARSIZE(res, size);
+	res->flag = flag;
+
+	if (!allistrue)
+	{
+		if (sign)
+			memcpy(GETSIGN(res), sign, siglen);
+		else
+			memset(GETSIGN(res), 0, siglen);
+	}
+
+	return res;
+}
+
 
 /*********************************************************************
 ** intbig functions
 *********************************************************************/
 static bool
-_intbig_overlap(GISTTYPE *a, ArrayType *b)
+_intbig_overlap(GISTTYPE *a, ArrayType *b, int siglen)
 {
 	int			num = ARRNELEMS(b);
 	int32	   *ptr = ARRPTR(b);
@@ -54,7 +78,7 @@ _intbig_overlap(GISTTYPE *a, ArrayType *b)
 
 	while (num--)
 	{
-		if (GETBIT(GETSIGN(a), HASHVAL(*ptr)))
+		if (GETBIT(GETSIGN(a), HASHVAL(*ptr, siglen)))
 			return true;
 		ptr++;
 	}
@@ -63,7 +87,7 @@ _intbig_overlap(GISTTYPE *a, ArrayType *b)
 }
 
 static bool
-_intbig_contains(GISTTYPE *a, ArrayType *b)
+_intbig_contains(GISTTYPE *a, ArrayType *b, int siglen)
 {
 	int			num = ARRNELEMS(b);
 	int32	   *ptr = ARRPTR(b);
@@ -72,7 +96,7 @@ _intbig_contains(GISTTYPE *a, ArrayType *b)
 
 	while (num--)
 	{
-		if (!GETBIT(GETSIGN(a), HASHVAL(*ptr)))
+		if (!GETBIT(GETSIGN(a), HASHVAL(*ptr, siglen)))
 			return false;
 		ptr++;
 	}
@@ -86,6 +110,7 @@ g_intbig_same(PG_FUNCTION_ARGS)
 	GISTTYPE   *a = (GISTTYPE *) PG_GETARG_POINTER(0);
 	GISTTYPE   *b = (GISTTYPE *) PG_GETARG_POINTER(1);
 	bool	   *result = (bool *) PG_GETARG_POINTER(2);
+	int			siglen = GET_SIGLEN();
 
 	if (ISALLTRUE(a) && ISALLTRUE(b))
 		*result = true;
@@ -100,7 +125,7 @@ g_intbig_same(PG_FUNCTION_ARGS)
 					sb = GETSIGN(b);
 
 		*result = true;
-		LOOPBYTE
+		LOOPBYTE(siglen)
 		{
 			if (sa[i] != sb[i])
 			{
@@ -116,6 +141,7 @@ Datum
 g_intbig_compress(PG_FUNCTION_ARGS)
 {
 	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	int			siglen = GET_SIGLEN();
 
 	if (entry->leafkey)
 	{
@@ -123,7 +149,7 @@ g_intbig_compress(PG_FUNCTION_ARGS)
 		ArrayType  *in = DatumGetArrayTypeP(entry->key);
 		int32	   *ptr;
 		int			num;
-		GISTTYPE   *res = (GISTTYPE *) palloc0(CALCGTSIZE(0));
+		GISTTYPE   *res = _intbig_alloc(false, siglen, NULL);
 
 		CHECKARRVALID(in);
 		if (ARRISEMPTY(in))
@@ -136,11 +162,10 @@ g_intbig_compress(PG_FUNCTION_ARGS)
 			ptr = ARRPTR(in);
 			num = ARRNELEMS(in);
 		}
-		SET_VARSIZE(res, CALCGTSIZE(0));
 
 		while (num--)
 		{
-			HASH(GETSIGN(res), *ptr);
+			HASH(GETSIGN(res), *ptr, siglen);
 			ptr++;
 		}
 
@@ -161,16 +186,13 @@ g_intbig_compress(PG_FUNCTION_ARGS)
 		BITVECP		sign = GETSIGN(DatumGetPointer(entry->key));
 		GISTTYPE   *res;
 
-		LOOPBYTE
+		LOOPBYTE(siglen)
 		{
 			if ((sign[i] & 0xff) != 0xff)
 				PG_RETURN_POINTER(entry);
 		}
 
-		res = (GISTTYPE *) palloc(CALCGTSIZE(ALLISTRUE));
-		SET_VARSIZE(res, CALCGTSIZE(ALLISTRUE));
-		res->flag = ALLISTRUE;
-
+		res = _intbig_alloc(true, siglen, sign);
 		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
 		gistentryinit(*retval, PointerGetDatum(res),
 					  entry->rel, entry->page,
@@ -184,19 +206,19 @@ g_intbig_compress(PG_FUNCTION_ARGS)
 
 
 static int32
-sizebitvec(BITVECP sign)
+sizebitvec(BITVECP sign, int siglen)
 {
-	return pg_popcount(sign, SIGLEN);
+	return pg_popcount(sign, siglen);
 }
 
 static int
-hemdistsign(BITVECP a, BITVECP b)
+hemdistsign(BITVECP a, BITVECP b, int siglen)
 {
 	int			i,
 				diff,
 				dist = 0;
 
-	LOOPBYTE
+	LOOPBYTE(siglen)
 	{
 		diff = (unsigned char) (a[i] ^ b[i]);
 		/* Using the popcount functions here isn't likely to win */
@@ -206,19 +228,19 @@ hemdistsign(BITVECP a, BITVECP b)
 }
 
 static int
-hemdist(GISTTYPE *a, GISTTYPE *b)
+hemdist(GISTTYPE *a, GISTTYPE *b, int siglen)
 {
 	if (ISALLTRUE(a))
 	{
 		if (ISALLTRUE(b))
 			return 0;
 		else
-			return SIGLENBIT - sizebitvec(GETSIGN(b));
+			return SIGLENBIT(siglen) - sizebitvec(GETSIGN(b), siglen);
 	}
 	else if (ISALLTRUE(b))
-		return SIGLENBIT - sizebitvec(GETSIGN(a));
+		return SIGLENBIT(siglen) - sizebitvec(GETSIGN(a), siglen);
 
-	return hemdistsign(GETSIGN(a), GETSIGN(b));
+	return hemdistsign(GETSIGN(a), GETSIGN(b), siglen);
 }
 
 Datum
@@ -228,14 +250,14 @@ g_intbig_decompress(PG_FUNCTION_ARGS)
 }
 
 static int32
-unionkey(BITVECP sbase, GISTTYPE *add)
+unionkey(BITVECP sbase, GISTTYPE *add, int siglen)
 {
 	int32		i;
 	BITVECP		sadd = GETSIGN(add);
 
 	if (ISALLTRUE(add))
 		return 1;
-	LOOPBYTE
+	LOOPBYTE(siglen)
 		sbase[i] |= sadd[i];
 	return 0;
 }
@@ -245,29 +267,22 @@ g_intbig_union(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 	int		   *size = (int *) PG_GETARG_POINTER(1);
-	BITVEC		base;
-	int32		i,
-				len;
-	int32		flag = 0;
-	GISTTYPE   *result;
+	int			siglen = GET_SIGLEN();
+	int32		i;
+	GISTTYPE   *result = _intbig_alloc(false, siglen, NULL);
+	BITVECP		base = GETSIGN(result);
 
-	MemSet((void *) base, 0, sizeof(BITVEC));
 	for (i = 0; i < entryvec->n; i++)
 	{
-		if (unionkey(base, GETENTRY(entryvec, i)))
+		if (unionkey(base, GETENTRY(entryvec, i), siglen))
 		{
-			flag = ALLISTRUE;
+			result->flag |= ALLISTRUE;
+			SET_VARSIZE(result, CALCGTSIZE(ALLISTRUE, siglen));
 			break;
 		}
 	}
 
-	len = CALCGTSIZE(flag);
-	result = (GISTTYPE *) palloc(len);
-	SET_VARSIZE(result, len);
-	result->flag = flag;
-	if (!ISALLTRUE(result))
-		memcpy((void *) GETSIGN(result), (void *) base, sizeof(BITVEC));
-	*size = len;
+	*size = VARSIZE(result);
 
 	PG_RETURN_POINTER(result);
 }
@@ -280,8 +295,9 @@ g_intbig_penalty(PG_FUNCTION_ARGS)
 	float	   *penalty = (float *) PG_GETARG_POINTER(2);
 	GISTTYPE   *origval = (GISTTYPE *) DatumGetPointer(origentry->key);
 	GISTTYPE   *newval = (GISTTYPE *) DatumGetPointer(newentry->key);
+	int			siglen = GET_SIGLEN();
 
-	*penalty = hemdist(origval, newval);
+	*penalty = hemdist(origval, newval, siglen);
 	PG_RETURN_POINTER(penalty);
 }
 
@@ -304,6 +320,7 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 	GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
+	int			siglen = GET_SIGLEN();
 	OffsetNumber k,
 				j;
 	GISTTYPE   *datum_l,
@@ -336,7 +353,7 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 		_k = GETENTRY(entryvec, k);
 		for (j = OffsetNumberNext(k); j <= maxoff; j = OffsetNumberNext(j))
 		{
-			size_waste = hemdist(_k, GETENTRY(entryvec, j));
+			size_waste = hemdist(_k, GETENTRY(entryvec, j), siglen);
 			if (size_waste > waste)
 			{
 				waste = size_waste;
@@ -358,32 +375,10 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 	}
 
 	/* form initial .. */
-	if (ISALLTRUE(GETENTRY(entryvec, seed_1)))
-	{
-		datum_l = (GISTTYPE *) palloc(GTHDRSIZE);
-		SET_VARSIZE(datum_l, GTHDRSIZE);
-		datum_l->flag = ALLISTRUE;
-	}
-	else
-	{
-		datum_l = (GISTTYPE *) palloc(GTHDRSIZE + SIGLEN);
-		SET_VARSIZE(datum_l, GTHDRSIZE + SIGLEN);
-		datum_l->flag = 0;
-		memcpy((void *) GETSIGN(datum_l), (void *) GETSIGN(GETENTRY(entryvec, seed_1)), sizeof(BITVEC));
-	}
-	if (ISALLTRUE(GETENTRY(entryvec, seed_2)))
-	{
-		datum_r = (GISTTYPE *) palloc(GTHDRSIZE);
-		SET_VARSIZE(datum_r, GTHDRSIZE);
-		datum_r->flag = ALLISTRUE;
-	}
-	else
-	{
-		datum_r = (GISTTYPE *) palloc(GTHDRSIZE + SIGLEN);
-		SET_VARSIZE(datum_r, GTHDRSIZE + SIGLEN);
-		datum_r->flag = 0;
-		memcpy((void *) GETSIGN(datum_r), (void *) GETSIGN(GETENTRY(entryvec, seed_2)), sizeof(BITVEC));
-	}
+	datum_l = _intbig_alloc(ISALLTRUE(GETENTRY(entryvec, seed_1)), siglen,
+							GETSIGN(GETENTRY(entryvec, seed_1)));
+	datum_r = _intbig_alloc(ISALLTRUE(GETENTRY(entryvec, seed_2)), siglen,
+							GETSIGN(GETENTRY(entryvec, seed_2)));
 
 	maxoff = OffsetNumberNext(maxoff);
 	/* sort before ... */
@@ -392,8 +387,8 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 	{
 		costvector[j - 1].pos = j;
 		_j = GETENTRY(entryvec, j);
-		size_alpha = hemdist(datum_l, _j);
-		size_beta = hemdist(datum_r, _j);
+		size_alpha = hemdist(datum_l, _j, siglen);
+		size_beta = hemdist(datum_r, _j, siglen);
 		costvector[j - 1].cost = Abs(size_alpha - size_beta);
 	}
 	qsort((void *) costvector, maxoff, sizeof(SPLITCOST), comparecost);
@@ -417,20 +412,20 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 			continue;
 		}
 		_j = GETENTRY(entryvec, j);
-		size_alpha = hemdist(datum_l, _j);
-		size_beta = hemdist(datum_r, _j);
+		size_alpha = hemdist(datum_l, _j, siglen);
+		size_beta = hemdist(datum_r, _j, siglen);
 
 		if (size_alpha < size_beta + WISH_F(v->spl_nleft, v->spl_nright, 0.00001))
 		{
 			if (ISALLTRUE(datum_l) || ISALLTRUE(_j))
 			{
 				if (!ISALLTRUE(datum_l))
-					MemSet((void *) union_l, 0xff, sizeof(BITVEC));
+					MemSet((void *) union_l, 0xff, siglen);
 			}
 			else
 			{
 				ptr = GETSIGN(_j);
-				LOOPBYTE
+				LOOPBYTE(siglen)
 					union_l[i] |= ptr[i];
 			}
 			*left++ = j;
@@ -441,12 +436,12 @@ g_intbig_picksplit(PG_FUNCTION_ARGS)
 			if (ISALLTRUE(datum_r) || ISALLTRUE(_j))
 			{
 				if (!ISALLTRUE(datum_r))
-					MemSet((void *) union_r, 0xff, sizeof(BITVEC));
+					MemSet((void *) union_r, 0xff, siglen);
 			}
 			else
 			{
 				ptr = GETSIGN(_j);
-				LOOPBYTE
+				LOOPBYTE(siglen)
 					union_r[i] |= ptr[i];
 			}
 			*right++ = j;
@@ -472,6 +467,7 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 
 	/* Oid		subtype = PG_GETARG_OID(3); */
 	bool	   *recheck = (bool *) PG_GETARG_POINTER(4);
+	int			siglen = GET_SIGLEN();
 	bool		retval;
 
 	/* All cases served by this function are inexact */
@@ -484,6 +480,7 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 	{
 		retval = signconsistent((QUERYTYPE *) query,
 								GETSIGN(DatumGetPointer(entry->key)),
+								siglen,
 								false);
 		PG_FREE_IF_COPY(query, 1);
 		PG_RETURN_BOOL(retval);
@@ -494,7 +491,8 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 	switch (strategy)
 	{
 		case RTOverlapStrategyNumber:
-			retval = _intbig_overlap((GISTTYPE *) DatumGetPointer(entry->key), query);
+			retval = _intbig_overlap((GISTTYPE *) DatumGetPointer(entry->key),
+									 query, siglen);
 			break;
 		case RTSameStrategyNumber:
 			if (GIST_LEAF(entry))
@@ -502,22 +500,18 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 				int			i,
 							num = ARRNELEMS(query);
 				int32	   *ptr = ARRPTR(query);
-				BITVEC		qp;
-				BITVECP		dq,
+				BITVECP		dq = palloc0(siglen),
 							de;
 
-				memset(qp, 0, sizeof(BITVEC));
-
 				while (num--)
 				{
-					HASH(qp, *ptr);
+					HASH(dq, *ptr, siglen);
 					ptr++;
 				}
 
 				de = GETSIGN((GISTTYPE *) DatumGetPointer(entry->key));
-				dq = qp;
 				retval = true;
-				LOOPBYTE
+				LOOPBYTE(siglen)
 				{
 					if (de[i] != dq[i])
 					{
@@ -526,13 +520,16 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 					}
 				}
 
+				pfree(dq);
 			}
 			else
-				retval = _intbig_contains((GISTTYPE *) DatumGetPointer(entry->key), query);
+				retval = _intbig_contains((GISTTYPE *) DatumGetPointer(entry->key),
+										  query, siglen);
 			break;
 		case RTContainsStrategyNumber:
 		case RTOldContainsStrategyNumber:
-			retval = _intbig_contains((GISTTYPE *) DatumGetPointer(entry->key), query);
+			retval = _intbig_contains((GISTTYPE *) DatumGetPointer(entry->key),
+									  query, siglen);
 			break;
 		case RTContainedByStrategyNumber:
 		case RTOldContainedByStrategyNumber:
@@ -541,22 +538,18 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 				int			i,
 							num = ARRNELEMS(query);
 				int32	   *ptr = ARRPTR(query);
-				BITVEC		qp;
-				BITVECP		dq,
+				BITVECP		dq = palloc0(siglen),
 							de;
 
-				memset(qp, 0, sizeof(BITVEC));
-
 				while (num--)
 				{
-					HASH(qp, *ptr);
+					HASH(dq, *ptr, siglen);
 					ptr++;
 				}
 
 				de = GETSIGN((GISTTYPE *) DatumGetPointer(entry->key));
-				dq = qp;
 				retval = true;
-				LOOPBYTE
+				LOOPBYTE(siglen)
 				{
 					if (de[i] & ~dq[i])
 					{
@@ -580,3 +573,17 @@ g_intbig_consistent(PG_FUNCTION_ARGS)
 	PG_FREE_IF_COPY(query, 1);
 	PG_RETURN_BOOL(retval);
 }
+
+Datum
+g_intbig_options(PG_FUNCTION_ARGS)
+{
+	local_relopts *relopts = (local_relopts *) PG_GETARG_POINTER(0);
+
+	init_local_reloptions(relopts, sizeof(GISTIntArrayBigOptions));
+	add_local_int_reloption(relopts, "siglen",
+							"signature length in bytes",
+							SIGLEN_DEFAULT, 1, SIGLEN_MAX,
+							offsetof(GISTIntArrayBigOptions, siglen));
+
+	PG_RETURN_VOID();
+}