Generalize hash and ordering support in amapi

Stop comparing access method OID values against HASH_AM_OID and
BTREE_AM_OID, and instead check the IndexAmRoutine for an index to see
if it advertises its ability to perform the necessary ordering,
hashing, or cross-type comparing functionality.  A field amcanorder
already existed, this uses it more widely.  Fields amcanhash and
amcancrosscompare are added for the other purposes.

Author: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com

6 files changed, 12 insertions, 0 deletions

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 60320440fc5..75a65ec9c75 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -256,6 +256,8 @@ brinhandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = BRIN_PROCNUM_OPTIONS;
 	amroutine->amcanorder = false;
 	amroutine->amcanorderbyop = false;
+	amroutine->amcanhash = false;
+	amroutine->amcancrosscompare = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index 1f9e58c4f1f..5b643619754 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -43,6 +43,8 @@ ginhandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = GIN_OPTIONS_PROC;
 	amroutine->amcanorder = false;
 	amroutine->amcanorderbyop = false;
+	amroutine->amcanhash = false;
+	amroutine->amcancrosscompare = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 4d858b65e1e..5482925a0f3 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -65,6 +65,8 @@ gisthandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = GIST_OPTIONS_PROC;
 	amroutine->amcanorder = false;
 	amroutine->amcanorderbyop = true;
+	amroutine->amcanhash = false;
+	amroutine->amcancrosscompare = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index b24aae415ea..a22845d7068 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -64,6 +64,8 @@ hashhandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = HASHOPTIONS_PROC;
 	amroutine->amcanorder = false;
 	amroutine->amcanorderbyop = false;
+	amroutine->amcanhash = true;
+	amroutine->amcancrosscompare = false;
 	amroutine->amcanbackward = true;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = false;
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index 411d5ac0b5f..45ea6afba1d 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -107,6 +107,8 @@ bthandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = BTOPTIONS_PROC;
 	amroutine->amcanorder = true;
 	amroutine->amcanorderbyop = false;
+	amroutine->amcanhash = false;
+	amroutine->amcancrosscompare = true;
 	amroutine->amcanbackward = true;
 	amroutine->amcanunique = true;
 	amroutine->amcanmulticol = true;
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 367c36ef9af..7e56b1e6b95 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -50,6 +50,8 @@ spghandler(PG_FUNCTION_ARGS)
 	amroutine->amoptsprocnum = SPGIST_OPTIONS_PROC;
 	amroutine->amcanorder = false;
 	amroutine->amcanorderbyop = true;
+	amroutine->amcanhash = false;
+	amroutine->amcancrosscompare = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = false;