6 files changed, 118 insertions, 0 deletions
diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 4289142e20b..ccf824bbdb2 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -298,6 +298,8 @@ brinhandler(PG_FUNCTION_ARGS)
 	amroutine->amestimateparallelscan = NULL;
 	amroutine->aminitparallelscan = NULL;
 	amroutine->amparallelrescan = NULL;
+	amroutine->amtranslatestrategy = NULL;
+	amroutine->amtranslatecmptype = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index b6bc75b44e3..70f8086db7b 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -107,6 +107,8 @@ gisthandler(PG_FUNCTION_ARGS)
 	amroutine->amestimateparallelscan = NULL;
 	amroutine->aminitparallelscan = NULL;
 	amroutine->amparallelrescan = NULL;
+	amroutine->amtranslatestrategy = NULL;
+	amroutine->amtranslatecmptype = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index df8409ab233..63b568e7f24 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -21,6 +21,7 @@
 #include "access/hash.h"
 #include "access/hash_xlog.h"
 #include "access/relscan.h"
+#include "access/stratnum.h"
 #include "access/tableam.h"
 #include "access/xloginsert.h"
 #include "commands/progress.h"
@@ -105,6 +106,8 @@ hashhandler(PG_FUNCTION_ARGS)
 	amroutine->amestimateparallelscan = NULL;
 	amroutine->aminitparallelscan = NULL;
 	amroutine->amparallelrescan = NULL;
+	amroutine->amtranslatestrategy = hashtranslatestrategy;
+	amroutine->amtranslatecmptype = hashtranslatecmptype;
 
 	PG_RETURN_POINTER(amroutine);
 }
@@ -922,3 +925,19 @@ hashbucketcleanup(Relation rel, Bucket cur_bucket, Buffer bucket_buf,
 	else
 		LockBuffer(bucket_buf, BUFFER_LOCK_UNLOCK);
 }
+
+CompareType
+hashtranslatestrategy(StrategyNumber strategy, Oid opfamily, Oid opcintype)
+{
+	if (strategy == HTEqualStrategyNumber)
+		return COMPARE_EQ;
+	return COMPARE_INVALID;
+}
+
+StrategyNumber
+hashtranslatecmptype(CompareType cmptype, Oid opfamily, Oid opcintype)
+{
+	if (cmptype == COMPARE_EQ)
+		return HTEqualStrategyNumber;
+	return InvalidStrategy;
+}
diff --git a/src/backend/access/index/amapi.c b/src/backend/access/index/amapi.c
index 3522bcaa401..5f53f49ec32 100644
--- a/src/backend/access/index/amapi.c
+++ b/src/backend/access/index/amapi.c
@@ -108,6 +108,56 @@ GetIndexAmRoutineByAmId(Oid amoid, bool noerror)
 
 
 /*
+ * IndexAmTranslateStrategy - given an access method and strategy, get the
+ * corresponding compare type.
+ *
+ * If missing_ok is false, throw an error if no compare type is found.  If
+ * true, just return COMPARE_INVALID.
+ */
+CompareType
+IndexAmTranslateStrategy(StrategyNumber strategy, Oid amoid, Oid opfamily, Oid opcintype, bool missing_ok)
+{
+	CompareType result;
+	IndexAmRoutine *amroutine;
+
+	amroutine = GetIndexAmRoutineByAmId(amoid, false);
+	if (amroutine->amtranslatestrategy)
+		result = amroutine->amtranslatestrategy(strategy, opfamily, opcintype);
+	else
+		result = COMPARE_INVALID;
+
+	if (!missing_ok && result == COMPARE_INVALID)
+		elog(ERROR, "could not translate strategy number %d for index AM %u", strategy, amoid);
+
+	return result;
+}
+
+/*
+ * IndexAmTranslateCompareType - given an access method and compare type, get
+ * the corresponding strategy number.
+ *
+ * If missing_ok is false, throw an error if no strategy is found correlating
+ * to the given cmptype.  If true, just return InvalidStrategy.
+ */
+StrategyNumber
+IndexAmTranslateCompareType(CompareType cmptype, Oid amoid, Oid opfamily, Oid opcintype, bool missing_ok)
+{
+	StrategyNumber result;
+	IndexAmRoutine *amroutine;
+
+	amroutine = GetIndexAmRoutineByAmId(amoid, false);
+	if (amroutine->amtranslatecmptype)
+		result = amroutine->amtranslatecmptype(cmptype, opfamily, opcintype);
+	else
+		result = InvalidStrategy;
+
+	if (!missing_ok && result == InvalidStrategy)
+		elog(ERROR, "could not translate compare type %u for index AM %u", cmptype, amoid);
+
+	return result;
+}
+
+/*
  * Ask appropriate access method to validate the specified opclass.
  */
 Datum
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index 3d617f168f5..971405e89af 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -20,6 +20,7 @@
 
 #include "access/nbtree.h"
 #include "access/relscan.h"
+#include "access/stratnum.h"
 #include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "nodes/execnodes.h"
@@ -148,6 +149,8 @@ bthandler(PG_FUNCTION_ARGS)
 	amroutine->amestimateparallelscan = btestimateparallelscan;
 	amroutine->aminitparallelscan = btinitparallelscan;
 	amroutine->amparallelrescan = btparallelrescan;
+	amroutine->amtranslatestrategy = bttranslatestrategy;
+	amroutine->amtranslatecmptype = bttranslatecmptype;
 
 	PG_RETURN_POINTER(amroutine);
 }
@@ -1508,3 +1511,43 @@ btgettreeheight(Relation rel)
 {
 	return _bt_getrootheight(rel);
 }
+
+CompareType
+bttranslatestrategy(StrategyNumber strategy, Oid opfamily, Oid opcintype)
+{
+	switch (strategy)
+	{
+		case BTLessStrategyNumber:
+			return COMPARE_LT;
+		case BTLessEqualStrategyNumber:
+			return COMPARE_LE;
+		case BTEqualStrategyNumber:
+			return COMPARE_EQ;
+		case BTGreaterEqualStrategyNumber:
+			return COMPARE_GE;
+		case BTGreaterStrategyNumber:
+			return COMPARE_GT;
+		default:
+			return COMPARE_INVALID;
+	}
+}
+
+StrategyNumber
+bttranslatecmptype(CompareType cmptype, Oid opfamily, Oid opcintype)
+{
+	switch (cmptype)
+	{
+		case COMPARE_LT:
+			return BTLessStrategyNumber;
+		case COMPARE_LE:
+			return BTLessEqualStrategyNumber;
+		case COMPARE_EQ:
+			return BTEqualStrategyNumber;
+		case COMPARE_GE:
+			return BTGreaterEqualStrategyNumber;
+		case COMPARE_GT:
+			return BTGreaterStrategyNumber;
+		default:
+			return InvalidStrategy;
+	}
+}
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 6e968048917..367c36ef9af 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -92,6 +92,8 @@ spghandler(PG_FUNCTION_ARGS)
 	amroutine->amestimateparallelscan = NULL;
 	amroutine->aminitparallelscan = NULL;
 	amroutine->amparallelrescan = NULL;
+	amroutine->amtranslatestrategy = NULL;
+	amroutine->amtranslatecmptype = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }