Re: Rethinking opclass member checks and dependency strength - Mailing list pgsql-hackers

I wrote:
> Still haven't got a better naming idea, but in the meantime here's
> a rebase to fix a conflict with 612a1ab76.

I see from the cfbot that this needs another rebase, so here 'tis.
No changes in the patch itself.

            regards, tom lane

diff --git a/contrib/bloom/blutils.c b/contrib/bloom/blutils.c
index d3bf866..663ff7e 100644
--- a/contrib/bloom/blutils.c
+++ b/contrib/bloom/blutils.c
@@ -139,6 +139,7 @@ blhandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = NULL;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = blvalidate;
+    amroutine->amcheckmembers = NULL;
     amroutine->ambeginscan = blbeginscan;
     amroutine->amrescan = blrescan;
     amroutine->amgettuple = NULL;
diff --git a/doc/src/sgml/indexam.sgml b/doc/src/sgml/indexam.sgml
index 37f8d87..d76d17d 100644
--- a/doc/src/sgml/indexam.sgml
+++ b/doc/src/sgml/indexam.sgml
@@ -141,6 +141,7 @@ typedef struct IndexAmRoutine
     amproperty_function amproperty;     /* can be NULL */
     ambuildphasename_function ambuildphasename;   /* can be NULL */
     amvalidate_function amvalidate;
+    amcheckmembers_function amcheckmembers; /* can be NULL */
     ambeginscan_function ambeginscan;
     amrescan_function amrescan;
     amgettuple_function amgettuple;     /* can be NULL */
@@ -500,7 +501,48 @@ amvalidate (Oid opclassoid);
    the access method can reasonably do that.  For example, this might include
    testing that all required support functions are provided.
    The <function>amvalidate</function> function must return false if the opclass is
-   invalid.  Problems should be reported with <function>ereport</function> messages.
+   invalid.  Problems should be reported with <function>ereport</function>
+   messages, typically at <literal>INFO</literal> level.
+  </para>
+
+  <para>
+<programlisting>
+void
+amcheckmembers (Oid opfamilyoid,
+                Oid opclassoid,
+                List *operators,
+                List *functions);
+</programlisting>
+   Validate proposed operator and function members of an operator family,
+   so far as the access method can reasonably do that, and set their
+   dependency types if the default is not satisfactory.  This is called
+   during <command>CREATE OPERATOR CLASS</command> and during
+   <command>ALTER OPERATOR FAMILY ADD</command>; in the latter
+   case <parameter>opclassoid</parameter> is <literal>InvalidOid</literal>.
+   The <type>List</type> arguments are lists
+   of <structname>OpFamilyMember</structname> structs, as defined
+   in <filename>amapi.h</filename>.
+
+   Tests done by this function will typically be a subset of those
+   performed by <function>amvalidate</function>,
+   since <function>amcheckmembers</function> cannot assume that it is
+   seeing a complete set of members.  For example, it would be reasonable
+   to check the signature of a support function, but not to check whether
+   all required support functions are provided.  Any problems can be
+   reported by throwing an error.
+
+   The dependency-related fields of
+   the <structname>OpFamilyMember</structname> structs are initialized by
+   the core code to create hard dependencies on the opclass if this
+   is <command>CREATE OPERATOR CLASS</command>, or soft dependencies on the
+   opfamily if this is <command>ALTER OPERATOR FAMILY ADD</command>.
+   <function>amcheckmembers</function> can adjust these fields if some other
+   behavior is more appropriate.  For example, GIN, GiST, and SP-GiST
+   always set operator members to have soft dependencies on the opfamily,
+   since the connection between an operator and an opclass is relatively
+   weak in these index types; so it is reasonable to allow operator members
+   to be added and removed freely.  Optional support functions are typically
+   also given soft dependencies, so that they can be removed if necessary.
   </para>


diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 7db3ae5..b911029 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -120,6 +120,7 @@ brinhandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = NULL;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = brinvalidate;
+    amroutine->amcheckmembers = NULL;
     amroutine->ambeginscan = brinbeginscan;
     amroutine->amrescan = brinrescan;
     amroutine->amgettuple = NULL;
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index a400f1f..26aa152 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -71,6 +71,7 @@ ginhandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = NULL;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = ginvalidate;
+    amroutine->amcheckmembers = gincheckmembers;
     amroutine->ambeginscan = ginbeginscan;
     amroutine->amrescan = ginrescan;
     amroutine->amgettuple = NULL;
diff --git a/src/backend/access/gin/ginvalidate.c b/src/backend/access/gin/ginvalidate.c
index 1e3046f..739006a 100644
--- a/src/backend/access/gin/ginvalidate.c
+++ b/src/backend/access/gin/ginvalidate.c
@@ -271,3 +271,64 @@ ginvalidate(Oid opclassoid)

     return result;
 }
+
+/*
+ * Prechecking function for adding operators/functions to a GIN opfamily.
+ */
+void
+gincheckmembers(Oid opfamilyoid,
+                Oid opclassoid,
+                List *operators,
+                List *functions)
+{
+    ListCell   *lc;
+
+    /*
+     * Operator members of a GIN opfamily should never have hard dependencies,
+     * since their connection to the opfamily depends only on what the support
+     * functions think, and that can be altered.  For consistency, we make all
+     * soft dependencies point to the opfamily, though a soft dependency on
+     * the opclass would work as well in the CREATE OPERATOR CLASS case.
+     */
+    foreach(lc, operators)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        op->ref_is_hard = false;
+        op->ref_is_family = true;
+        op->refobjid = opfamilyoid;
+    }
+
+    /*
+     * Required support functions should have hard dependencies.  Preferably
+     * those are just dependencies on the opclass, but if we're in ALTER
+     * OPERATOR FAMILY, we leave the dependency pointing at the whole
+     * opfamily.  (Given that GIN opclasses generally don't share opfamilies,
+     * it seems unlikely to be worth working harder.)
+     */
+    foreach(lc, functions)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        switch (op->number)
+        {
+            case GIN_EXTRACTVALUE_PROC:
+            case GIN_EXTRACTQUERY_PROC:
+                /* Required support function */
+                op->ref_is_hard = true;
+                break;
+            case GIN_COMPARE_PROC:
+            case GIN_CONSISTENT_PROC:
+            case GIN_COMPARE_PARTIAL_PROC:
+            case GIN_TRICONSISTENT_PROC:
+                /* Optional, so force it to be a soft family dependency */
+                op->ref_is_hard = false;
+                op->ref_is_family = true;
+                op->refobjid = opfamilyoid;
+                break;
+            default:
+                /* Probably we should throw error here */
+                break;
+        }
+    }
+}
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 9eee538..90826c2 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -92,6 +92,7 @@ gisthandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = gistproperty;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = gistvalidate;
+    amroutine->amcheckmembers = gistcheckmembers;
     amroutine->ambeginscan = gistbeginscan;
     amroutine->amrescan = gistrescan;
     amroutine->amgettuple = gistgettuple;
diff --git a/src/backend/access/gist/gistvalidate.c b/src/backend/access/gist/gistvalidate.c
index a285736..2eac5ab 100644
--- a/src/backend/access/gist/gistvalidate.c
+++ b/src/backend/access/gist/gistvalidate.c
@@ -279,3 +279,68 @@ gistvalidate(Oid opclassoid)

     return result;
 }
+
+/*
+ * Prechecking function for adding operators/functions to a GiST opfamily.
+ */
+void
+gistcheckmembers(Oid opfamilyoid,
+                 Oid opclassoid,
+                 List *operators,
+                 List *functions)
+{
+    ListCell   *lc;
+
+    /*
+     * Operator members of a GiST opfamily should never have hard
+     * dependencies, since their connection to the opfamily depends only on
+     * what the support functions think, and that can be altered.  For
+     * consistency, we make all soft dependencies point to the opfamily,
+     * though a soft dependency on the opclass would work as well in the
+     * CREATE OPERATOR CLASS case.
+     */
+    foreach(lc, operators)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        op->ref_is_hard = false;
+        op->ref_is_family = true;
+        op->refobjid = opfamilyoid;
+    }
+
+    /*
+     * Required support functions should have hard dependencies.  Preferably
+     * those are just dependencies on the opclass, but if we're in ALTER
+     * OPERATOR FAMILY, we leave the dependency pointing at the whole
+     * opfamily.  (Given that GiST opclasses generally don't share opfamilies,
+     * it seems unlikely to be worth working harder.)
+     */
+    foreach(lc, functions)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        switch (op->number)
+        {
+            case GIST_CONSISTENT_PROC:
+            case GIST_UNION_PROC:
+            case GIST_PENALTY_PROC:
+            case GIST_PICKSPLIT_PROC:
+            case GIST_EQUAL_PROC:
+                /* Required support function */
+                op->ref_is_hard = true;
+                break;
+            case GIST_COMPRESS_PROC:
+            case GIST_DECOMPRESS_PROC:
+            case GIST_DISTANCE_PROC:
+            case GIST_FETCH_PROC:
+                /* Optional, so force it to be a soft family dependency */
+                op->ref_is_hard = false;
+                op->ref_is_family = true;
+                op->refobjid = opfamilyoid;
+                break;
+            default:
+                /* Probably we should throw error here */
+                break;
+        }
+    }
+}
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 3ec6d52..4eaba8b 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -89,6 +89,7 @@ hashhandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = NULL;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = hashvalidate;
+    amroutine->amcheckmembers = hashcheckmembers;
     amroutine->ambeginscan = hashbeginscan;
     amroutine->amrescan = hashrescan;
     amroutine->amgettuple = hashgettuple;
diff --git a/src/backend/access/hash/hashvalidate.c b/src/backend/access/hash/hashvalidate.c
index 7b08ed5..b2ee7ee 100644
--- a/src/backend/access/hash/hashvalidate.c
+++ b/src/backend/access/hash/hashvalidate.c
@@ -16,6 +16,8 @@
 #include "access/amvalidate.h"
 #include "access/hash.h"
 #include "access/htup_details.h"
+#include "access/xact.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_amop.h"
 #include "catalog/pg_amproc.h"
 #include "catalog/pg_opclass.h"
@@ -25,6 +27,7 @@
 #include "parser/parse_coerce.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
+#include "utils/lsyscache.h"
 #include "utils/regproc.h"
 #include "utils/syscache.h"

@@ -338,3 +341,96 @@ check_hash_func_signature(Oid funcid, int16 amprocnum, Oid argtype)
     ReleaseSysCache(tp);
     return result;
 }
+
+/*
+ * Prechecking function for adding operators/functions to a hash opfamily.
+ */
+void
+hashcheckmembers(Oid opfamilyoid,
+                 Oid opclassoid,
+                 List *operators,
+                 List *functions)
+{
+    Oid            opcintype;
+    ListCell   *lc;
+
+    /*
+     * Hash operators and required support functions are always "loose"
+     * members of the opfamily if they are cross-type.  If they are not
+     * cross-type, we prefer to tie them to the appropriate opclass ... but if
+     * the user hasn't created one, we can't do that, and must fall back to
+     * using the opfamily dependency.  (We mustn't force creation of an
+     * opclass in such a case, as leaving an incomplete opclass laying about
+     * would be bad.  Throwing an error is another undesirable alternative.)
+     *
+     * This behavior results in a bit of a dump/reload hazard, in that the
+     * order of restoring objects could affect what dependencies we end up
+     * with.  pg_dump's existing behavior will preserve the dependency choices
+     * in most cases, but not if a cross-type operator has been bound tightly
+     * into an opclass.  That's a mistake anyway, so silently "fixing" it
+     * isn't awful.
+     *
+     * Optional support functions are always "loose" family members.
+     *
+     * To avoid repeated lookups, we remember the most recently used opclass's
+     * input type.
+     */
+    if (OidIsValid(opclassoid))
+    {
+        /* During CREATE OPERATOR CLASS, need CCI to see the pg_opclass row */
+        CommandCounterIncrement();
+        opcintype = get_opclass_input_type(opclassoid);
+    }
+    else
+        opcintype = InvalidOid;
+
+    /*
+     * We handle operators and support functions almost identically, so rather
+     * than duplicate this code block, just join the lists.
+     */
+    foreach(lc, list_concat_copy(operators, functions))
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        if (op->is_func && op->number != HASHSTANDARD_PROC)
+        {
+            /* Optional support proc, so always a soft family dependency */
+            op->ref_is_hard = false;
+            op->ref_is_family = true;
+            op->refobjid = opfamilyoid;
+        }
+        else if (op->lefttype != op->righttype)
+        {
+            /* Cross-type, so always a soft family dependency */
+            op->ref_is_hard = false;
+            op->ref_is_family = true;
+            op->refobjid = opfamilyoid;
+        }
+        else
+        {
+            /* Not cross-type; is there a suitable opclass? */
+            if (op->lefttype != opcintype)
+            {
+                /* Avoid repeating this expensive lookup, even if it fails */
+                opcintype = op->lefttype;
+                opclassoid = opclass_for_family_datatype(HASH_AM_OID,
+                                                         opfamilyoid,
+                                                         opcintype);
+            }
+            if (OidIsValid(opclassoid))
+            {
+                /* Hard dependency on opclass */
+                op->ref_is_hard = true;
+                op->ref_is_family = false;
+                op->refobjid = opclassoid;
+            }
+            else
+            {
+                /* We're stuck, so make a soft dependency on the opfamily */
+                op->ref_is_hard = false;
+                op->ref_is_family = true;
+                op->refobjid = opfamilyoid;
+            }
+        }
+    }
+}
diff --git a/src/backend/access/index/amvalidate.c b/src/backend/access/index/amvalidate.c
index 24d4975..0c5f3aa 100644
--- a/src/backend/access/index/amvalidate.c
+++ b/src/backend/access/index/amvalidate.c
@@ -1,7 +1,8 @@
 /*-------------------------------------------------------------------------
  *
  * amvalidate.c
- *      Support routines for index access methods' amvalidate functions.
+ *      Support routines for index access methods' amvalidate and
+ *      amcheckmembers functions.
  *
  * Copyright (c) 2016-2020, PostgreSQL Global Development Group
  *
@@ -222,21 +223,28 @@ check_amop_signature(Oid opno, Oid restype, Oid lefttype, Oid righttype)
 }

 /*
- * Is the datatype a legitimate input type for the btree opfamily?
+ * Get the OID of the opclass belonging to an opfamily and accepting
+ * the specified type as input type.  Returns InvalidOid if no such opclass.
+ *
+ * If there is more than one such opclass, you get a random one of them.
+ * Since that shouldn't happen, we don't waste cycles checking.
+ *
+ * We could look up the AM's OID from the opfamily, but all existing callers
+ * know that or can get it without an extra lookup, so we make them pass it.
  */
-bool
-opfamily_can_sort_type(Oid opfamilyoid, Oid datatypeoid)
+Oid
+opclass_for_family_datatype(Oid amoid, Oid opfamilyoid, Oid datatypeoid)
 {
-    bool        result = false;
+    Oid            result = InvalidOid;
     CatCList   *opclist;
     int            i;

     /*
-     * We search through all btree opclasses to see if one matches.  This is a
-     * bit inefficient but there is no better index available.  It also saves
-     * making an explicit check that the opfamily belongs to btree.
+     * We search through all the AM's opclasses to see if one matches.  This
+     * is a bit inefficient but there is no better index available.  It also
+     * saves making an explicit check that the opfamily belongs to the AM.
      */
-    opclist = SearchSysCacheList1(CLAAMNAMENSP, ObjectIdGetDatum(BTREE_AM_OID));
+    opclist = SearchSysCacheList1(CLAAMNAMENSP, ObjectIdGetDatum(amoid));

     for (i = 0; i < opclist->n_members; i++)
     {
@@ -246,7 +254,7 @@ opfamily_can_sort_type(Oid opfamilyoid, Oid datatypeoid)
         if (classform->opcfamily == opfamilyoid &&
             classform->opcintype == datatypeoid)
         {
-            result = true;
+            result = classform->oid;
             break;
         }
     }
@@ -255,3 +263,14 @@ opfamily_can_sort_type(Oid opfamilyoid, Oid datatypeoid)

     return result;
 }
+
+/*
+ * Is the datatype a legitimate input type for the btree opfamily?
+ */
+bool
+opfamily_can_sort_type(Oid opfamilyoid, Oid datatypeoid)
+{
+    return OidIsValid(opclass_for_family_datatype(BTREE_AM_OID,
+                                                  opfamilyoid,
+                                                  datatypeoid));
+}
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index 3629478..52b2386 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -142,6 +142,7 @@ bthandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = btproperty;
     amroutine->ambuildphasename = btbuildphasename;
     amroutine->amvalidate = btvalidate;
+    amroutine->amcheckmembers = btcheckmembers;
     amroutine->ambeginscan = btbeginscan;
     amroutine->amrescan = btrescan;
     amroutine->amgettuple = btgettuple;
diff --git a/src/backend/access/nbtree/nbtvalidate.c b/src/backend/access/nbtree/nbtvalidate.c
index 02905f7..1dba4e4 100644
--- a/src/backend/access/nbtree/nbtvalidate.c
+++ b/src/backend/access/nbtree/nbtvalidate.c
@@ -16,12 +16,15 @@
 #include "access/amvalidate.h"
 #include "access/htup_details.h"
 #include "access/nbtree.h"
+#include "access/xact.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_amop.h"
 #include "catalog/pg_amproc.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_type.h"
 #include "utils/builtins.h"
+#include "utils/lsyscache.h"
 #include "utils/regproc.h"
 #include "utils/syscache.h"

@@ -282,3 +285,96 @@ btvalidate(Oid opclassoid)

     return result;
 }
+
+/*
+ * Prechecking function for adding operators/functions to a btree opfamily.
+ */
+void
+btcheckmembers(Oid opfamilyoid,
+               Oid opclassoid,
+               List *operators,
+               List *functions)
+{
+    Oid            opcintype;
+    ListCell   *lc;
+
+    /*
+     * Btree operators and comparison support functions are always "loose"
+     * members of the opfamily if they are cross-type.  If they are not
+     * cross-type, we prefer to tie them to the appropriate opclass ... but if
+     * the user hasn't created one, we can't do that, and must fall back to
+     * using the opfamily dependency.  (We mustn't force creation of an
+     * opclass in such a case, as leaving an incomplete opclass laying about
+     * would be bad.  Throwing an error is another undesirable alternative.)
+     *
+     * This behavior results in a bit of a dump/reload hazard, in that the
+     * order of restoring objects could affect what dependencies we end up
+     * with.  pg_dump's existing behavior will preserve the dependency choices
+     * in most cases, but not if a cross-type operator has been bound tightly
+     * into an opclass.  That's a mistake anyway, so silently "fixing" it
+     * isn't awful.
+     *
+     * Optional support functions are always "loose" family members.
+     *
+     * To avoid repeated lookups, we remember the most recently used opclass's
+     * input type.
+     */
+    if (OidIsValid(opclassoid))
+    {
+        /* During CREATE OPERATOR CLASS, need CCI to see the pg_opclass row */
+        CommandCounterIncrement();
+        opcintype = get_opclass_input_type(opclassoid);
+    }
+    else
+        opcintype = InvalidOid;
+
+    /*
+     * We handle operators and support functions almost identically, so rather
+     * than duplicate this code block, just join the lists.
+     */
+    foreach(lc, list_concat_copy(operators, functions))
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        if (op->is_func && op->number != BTORDER_PROC)
+        {
+            /* Optional support proc, so always a soft family dependency */
+            op->ref_is_hard = false;
+            op->ref_is_family = true;
+            op->refobjid = opfamilyoid;
+        }
+        else if (op->lefttype != op->righttype)
+        {
+            /* Cross-type, so always a soft family dependency */
+            op->ref_is_hard = false;
+            op->ref_is_family = true;
+            op->refobjid = opfamilyoid;
+        }
+        else
+        {
+            /* Not cross-type; is there a suitable opclass? */
+            if (op->lefttype != opcintype)
+            {
+                /* Avoid repeating this expensive lookup, even if it fails */
+                opcintype = op->lefttype;
+                opclassoid = opclass_for_family_datatype(BTREE_AM_OID,
+                                                         opfamilyoid,
+                                                         opcintype);
+            }
+            if (OidIsValid(opclassoid))
+            {
+                /* Hard dependency on opclass */
+                op->ref_is_hard = true;
+                op->ref_is_family = false;
+                op->refobjid = opclassoid;
+            }
+            else
+            {
+                /* We're stuck, so make a soft dependency on the opfamily */
+                op->ref_is_hard = false;
+                op->ref_is_family = true;
+                op->refobjid = opfamilyoid;
+            }
+        }
+    }
+}
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 0efe05e..ea3be52 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -74,6 +74,7 @@ spghandler(PG_FUNCTION_ARGS)
     amroutine->amproperty = spgproperty;
     amroutine->ambuildphasename = NULL;
     amroutine->amvalidate = spgvalidate;
+    amroutine->amcheckmembers = spgcheckmembers;
     amroutine->ambeginscan = spgbeginscan;
     amroutine->amrescan = spgrescan;
     amroutine->amgettuple = spggettuple;
diff --git a/src/backend/access/spgist/spgvalidate.c b/src/backend/access/spgist/spgvalidate.c
index 3c433e9..a9aff99 100644
--- a/src/backend/access/spgist/spgvalidate.c
+++ b/src/backend/access/spgist/spgvalidate.c
@@ -303,3 +303,65 @@ spgvalidate(Oid opclassoid)

     return result;
 }
+
+/*
+ * Prechecking function for adding operators/functions to an SP-GiST opfamily.
+ */
+void
+spgcheckmembers(Oid opfamilyoid,
+                Oid opclassoid,
+                List *operators,
+                List *functions)
+{
+    ListCell   *lc;
+
+    /*
+     * Operator members of an SP-GiST opfamily should never have hard
+     * dependencies, since their connection to the opfamily depends only on
+     * what the support functions think, and that can be altered.  For
+     * consistency, we make all soft dependencies point to the opfamily,
+     * though a soft dependency on the opclass would work as well in the
+     * CREATE OPERATOR CLASS case.
+     */
+    foreach(lc, operators)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        op->ref_is_hard = false;
+        op->ref_is_family = true;
+        op->refobjid = opfamilyoid;
+    }
+
+    /*
+     * Required support functions should have hard dependencies.  Preferably
+     * those are just dependencies on the opclass, but if we're in ALTER
+     * OPERATOR FAMILY, we leave the dependency pointing at the whole
+     * opfamily.  (Given that SP-GiST opclasses generally don't share
+     * opfamilies, it seems unlikely to be worth working harder.)
+     */
+    foreach(lc, functions)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);
+
+        switch (op->number)
+        {
+            case SPGIST_CONFIG_PROC:
+            case SPGIST_CHOOSE_PROC:
+            case SPGIST_PICKSPLIT_PROC:
+            case SPGIST_INNER_CONSISTENT_PROC:
+            case SPGIST_LEAF_CONSISTENT_PROC:
+                /* Required support function */
+                op->ref_is_hard = true;
+                break;
+            case SPGIST_COMPRESS_PROC:
+                /* Optional, so force it to be a soft family dependency */
+                op->ref_is_hard = false;
+                op->ref_is_family = true;
+                op->refobjid = opfamilyoid;
+                break;
+            default:
+                /* Probably we should throw error here */
+                break;
+        }
+    }
+}
diff --git a/src/backend/commands/opclasscmds.c b/src/backend/commands/opclasscmds.c
index 7322cbc..e2ad0ed 100644
--- a/src/backend/commands/opclasscmds.c
+++ b/src/backend/commands/opclasscmds.c
@@ -27,7 +27,6 @@
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/objectaccess.h"
-#include "catalog/opfam_internal.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_amop.h"
 #include "catalog/pg_amproc.h"
@@ -62,12 +61,10 @@ static void processTypesSpec(List *args, Oid *lefttype, Oid *righttype);
 static void assignOperTypes(OpFamilyMember *member, Oid amoid, Oid typeoid);
 static void assignProcTypes(OpFamilyMember *member, Oid amoid, Oid typeoid,
                             int opclassOptsProcNum);
-static void addFamilyMember(List **list, OpFamilyMember *member, bool isProc);
-static void storeOperators(List *opfamilyname, Oid amoid,
-                           Oid opfamilyoid, Oid opclassoid,
+static void addFamilyMember(List **list, OpFamilyMember *member);
+static void storeOperators(List *opfamilyname, Oid amoid, Oid opfamilyoid,
                            List *operators, bool isAdd);
-static void storeProcedures(List *opfamilyname, Oid amoid,
-                            Oid opfamilyoid, Oid opclassoid,
+static void storeProcedures(List *opfamilyname, Oid amoid, Oid opfamilyoid,
                             List *procedures, bool isAdd);
 static void dropOperators(List *opfamilyname, Oid amoid, Oid opfamilyoid,
                           List *operators);
@@ -518,11 +515,12 @@ DefineOpClass(CreateOpClassStmt *stmt)

                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = false;
                 member->object = operOid;
                 member->number = item->number;
                 member->sortfamily = sortfamilyOid;
                 assignOperTypes(member, amoid, typeoid);
-                addFamilyMember(&operators, member, false);
+                addFamilyMember(&operators, member);
                 break;
             case OPCLASS_ITEM_FUNCTION:
                 if (item->number <= 0 || item->number > maxProcNumber)
@@ -541,6 +539,7 @@ DefineOpClass(CreateOpClassStmt *stmt)
 #endif
                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = true;
                 member->object = funcOid;
                 member->number = item->number;

@@ -550,7 +549,7 @@ DefineOpClass(CreateOpClassStmt *stmt)
                                      &member->lefttype, &member->righttype);

                 assignProcTypes(member, amoid, typeoid, optsProcNumber);
-                addFamilyMember(&procedures, member, true);
+                addFamilyMember(&procedures, member);
                 break;
             case OPCLASS_ITEM_STORAGETYPE:
                 if (OidIsValid(storageoid))
@@ -663,13 +662,45 @@ DefineOpClass(CreateOpClassStmt *stmt)
     heap_freetuple(tup);

     /*
+     * Now that we have the opclass OID, set up default dependency info for
+     * the pg_amop and pg_amproc entries.  Historically, CREATE OPERATOR CLASS
+     * has created hard dependencies on the opclass, so that's what we use.
+     */
+    foreach(l, operators)
+    {
+        OpFamilyMember *op = (OpFamilyMember *) lfirst(l);
+
+        op->ref_is_hard = true;
+        op->ref_is_family = false;
+        op->refobjid = opclassoid;
+    }
+    foreach(l, procedures)
+    {
+        OpFamilyMember *proc = (OpFamilyMember *) lfirst(l);
+
+        proc->ref_is_hard = true;
+        proc->ref_is_family = false;
+        proc->refobjid = opclassoid;
+    }
+
+    /*
+     * Let the index AM editorialize on the dependency choices.  It could also
+     * do further validation on the operators and functions, if it likes.
+     */
+    if (amroutine->amcheckmembers)
+        amroutine->amcheckmembers(opfamilyoid,
+                                  opclassoid,
+                                  operators,
+                                  procedures);
+
+    /*
      * Now add tuples to pg_amop and pg_amproc tying in the operators and
      * functions.  Dependencies on them are inserted, too.
      */
     storeOperators(stmt->opfamilyname, amoid, opfamilyoid,
-                   opclassoid, operators, false);
+                   operators, false);
     storeProcedures(stmt->opfamilyname, amoid, opfamilyoid,
-                    opclassoid, procedures, false);
+                    procedures, false);

     /* let event triggers know what happened */
     EventTriggerCollectCreateOpClass(stmt, opclassoid, operators, procedures);
@@ -842,6 +873,7 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
                  int maxOpNumber, int maxProcNumber, int optsProcNumber,
                  List *items)
 {
+    IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(amoid, false);
     List       *operators;        /* OpFamilyMember list for operators */
     List       *procedures;        /* OpFamilyMember list for support procs */
     ListCell   *l;
@@ -900,11 +932,17 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,

                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = false;
                 member->object = operOid;
                 member->number = item->number;
                 member->sortfamily = sortfamilyOid;
+                /* We can set up dependency fields immediately */
+                /* Historically, ALTER ADD has created soft dependencies */
+                member->ref_is_hard = false;
+                member->ref_is_family = true;
+                member->refobjid = opfamilyoid;
                 assignOperTypes(member, amoid, InvalidOid);
-                addFamilyMember(&operators, member, false);
+                addFamilyMember(&operators, member);
                 break;
             case OPCLASS_ITEM_FUNCTION:
                 if (item->number <= 0 || item->number > maxProcNumber)
@@ -924,8 +962,14 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,

                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = true;
                 member->object = funcOid;
                 member->number = item->number;
+                /* We can set up dependency fields immediately */
+                /* Historically, ALTER ADD has created soft dependencies */
+                member->ref_is_hard = false;
+                member->ref_is_family = true;
+                member->refobjid = opfamilyoid;

                 /* allow overriding of the function's actual arg types */
                 if (item->class_args)
@@ -933,7 +977,7 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
                                      &member->lefttype, &member->righttype);

                 assignProcTypes(member, amoid, InvalidOid, optsProcNumber);
-                addFamilyMember(&procedures, member, true);
+                addFamilyMember(&procedures, member);
                 break;
             case OPCLASS_ITEM_STORAGETYPE:
                 ereport(ERROR,
@@ -947,13 +991,23 @@ AlterOpFamilyAdd(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
     }

     /*
+     * Let the index AM editorialize on the dependency choices.  It could also
+     * do further validation on the operators and functions, if it likes.
+     */
+    if (amroutine->amcheckmembers)
+        amroutine->amcheckmembers(opfamilyoid,
+                                  InvalidOid,    /* no specific opclass */
+                                  operators,
+                                  procedures);
+
+    /*
      * Add tuples to pg_amop and pg_amproc tying in the operators and
      * functions.  Dependencies on them are inserted, too.
      */
     storeOperators(stmt->opfamilyname, amoid, opfamilyoid,
-                   InvalidOid, operators, true);
+                   operators, true);
     storeProcedures(stmt->opfamilyname, amoid, opfamilyoid,
-                    InvalidOid, procedures, true);
+                    procedures, true);

     /* make information available to event triggers */
     EventTriggerCollectAlterOpFam(stmt, opfamilyoid,
@@ -996,10 +1050,11 @@ AlterOpFamilyDrop(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
                 processTypesSpec(item->class_args, &lefttype, &righttype);
                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = false;
                 member->number = item->number;
                 member->lefttype = lefttype;
                 member->righttype = righttype;
-                addFamilyMember(&operators, member, false);
+                addFamilyMember(&operators, member);
                 break;
             case OPCLASS_ITEM_FUNCTION:
                 if (item->number <= 0 || item->number > maxProcNumber)
@@ -1011,10 +1066,11 @@ AlterOpFamilyDrop(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
                 processTypesSpec(item->class_args, &lefttype, &righttype);
                 /* Save the info */
                 member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
+                member->is_func = true;
                 member->number = item->number;
                 member->lefttype = lefttype;
                 member->righttype = righttype;
-                addFamilyMember(&procedures, member, true);
+                addFamilyMember(&procedures, member);
                 break;
             case OPCLASS_ITEM_STORAGETYPE:
                 /* grammar prevents this from appearing */
@@ -1323,7 +1379,7 @@ assignProcTypes(OpFamilyMember *member, Oid amoid, Oid typeoid,
  * duplicated strategy or proc number.
  */
 static void
-addFamilyMember(List **list, OpFamilyMember *member, bool isProc)
+addFamilyMember(List **list, OpFamilyMember *member)
 {
     ListCell   *l;

@@ -1335,7 +1391,7 @@ addFamilyMember(List **list, OpFamilyMember *member, bool isProc)
             old->lefttype == member->lefttype &&
             old->righttype == member->righttype)
         {
-            if (isProc)
+            if (member->is_func)
                 ereport(ERROR,
                         (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                          errmsg("function number %d for (%s,%s) appears more than once",
@@ -1357,13 +1413,10 @@ addFamilyMember(List **list, OpFamilyMember *member, bool isProc)
 /*
  * Dump the operators to pg_amop
  *
- * We also make dependency entries in pg_depend for the opfamily entries.
- * If opclassoid is valid then make an INTERNAL dependency on that opclass,
- * else make an AUTO dependency on the opfamily.
+ * We also make dependency entries in pg_depend for the pg_amop entries.
  */
 static void
-storeOperators(List *opfamilyname, Oid amoid,
-               Oid opfamilyoid, Oid opclassoid,
+storeOperators(List *opfamilyname, Oid amoid, Oid opfamilyoid,
                List *operators, bool isAdd)
 {
     Relation    rel;
@@ -1433,28 +1486,17 @@ storeOperators(List *opfamilyname, Oid amoid,
         referenced.objectId = op->object;
         referenced.objectSubId = 0;

-        if (OidIsValid(opclassoid))
-        {
-            /* if contained in an opclass, use a NORMAL dep on operator */
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+        /* see comments in amapi.h about dependency strength */
+        recordDependencyOn(&myself, &referenced,
+                           op->ref_is_hard ? DEPENDENCY_NORMAL : DEPENDENCY_AUTO);

-            /* ... and an INTERNAL dep on the opclass */
-            referenced.classId = OperatorClassRelationId;
-            referenced.objectId = opclassoid;
-            referenced.objectSubId = 0;
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
-        }
-        else
-        {
-            /* if "loose" in the opfamily, use a AUTO dep on operator */
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
+        referenced.classId = op->ref_is_family ? OperatorFamilyRelationId :
+            OperatorClassRelationId;
+        referenced.objectId = op->refobjid;
+        referenced.objectSubId = 0;

-            /* ... and an AUTO dep on the opfamily */
-            referenced.classId = OperatorFamilyRelationId;
-            referenced.objectId = opfamilyoid;
-            referenced.objectSubId = 0;
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
-        }
+        recordDependencyOn(&myself, &referenced,
+                           op->ref_is_hard ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);

         /* A search operator also needs a dep on the referenced opfamily */
         if (OidIsValid(op->sortfamily))
@@ -1462,8 +1504,11 @@ storeOperators(List *opfamilyname, Oid amoid,
             referenced.classId = OperatorFamilyRelationId;
             referenced.objectId = op->sortfamily;
             referenced.objectSubId = 0;
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+
+            recordDependencyOn(&myself, &referenced,
+                               op->ref_is_hard ? DEPENDENCY_NORMAL : DEPENDENCY_AUTO);
         }
+
         /* Post create hook of this access method operator */
         InvokeObjectPostCreateHook(AccessMethodOperatorRelationId,
                                    entryoid, 0);
@@ -1475,13 +1520,10 @@ storeOperators(List *opfamilyname, Oid amoid,
 /*
  * Dump the procedures (support routines) to pg_amproc
  *
- * We also make dependency entries in pg_depend for the opfamily entries.
- * If opclassoid is valid then make an INTERNAL dependency on that opclass,
- * else make an AUTO dependency on the opfamily.
+ * We also make dependency entries in pg_depend for the pg_amproc entries.
  */
 static void
-storeProcedures(List *opfamilyname, Oid amoid,
-                Oid opfamilyoid, Oid opclassoid,
+storeProcedures(List *opfamilyname, Oid amoid, Oid opfamilyoid,
                 List *procedures, bool isAdd)
 {
     Relation    rel;
@@ -1545,28 +1587,18 @@ storeProcedures(List *opfamilyname, Oid amoid,
         referenced.objectId = proc->object;
         referenced.objectSubId = 0;

-        if (OidIsValid(opclassoid))
-        {
-            /* if contained in an opclass, use a NORMAL dep on procedure */
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+        /* see comments in amapi.h about dependency strength */
+        recordDependencyOn(&myself, &referenced,
+                           proc->ref_is_hard ? DEPENDENCY_NORMAL : DEPENDENCY_AUTO);

-            /* ... and an INTERNAL dep on the opclass */
-            referenced.classId = OperatorClassRelationId;
-            referenced.objectId = opclassoid;
-            referenced.objectSubId = 0;
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
-        }
-        else
-        {
-            /* if "loose" in the opfamily, use a AUTO dep on procedure */
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
+        referenced.classId = proc->ref_is_family ? OperatorFamilyRelationId :
+            OperatorClassRelationId;
+        referenced.objectId = proc->refobjid;
+        referenced.objectSubId = 0;
+
+        recordDependencyOn(&myself, &referenced,
+                           proc->ref_is_hard ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);

-            /* ... and an AUTO dep on the opfamily */
-            referenced.classId = OperatorFamilyRelationId;
-            referenced.objectId = opfamilyoid;
-            referenced.objectSubId = 0;
-            recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
-        }
         /* Post create hook of access method procedure */
         InvokeObjectPostCreateHook(AccessMethodProcedureRelationId,
                                    entryoid, 0);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 1b90cbd..25fb77f 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -524,6 +524,8 @@ my %tests = (
                          FUNCTION 1 (int4, int4) btint4cmp(int4,int4),
                          FUNCTION 2 (int4, int4) btint4sortsupport(internal),
                          FUNCTION 4 (int4, int4) btequalimage(oid);',
+        # note: it's correct that btint8sortsupport and bigint btequalimage
+        # are included here:
         regexp => qr/^
             \QALTER OPERATOR FAMILY dump_test.op_family USING btree ADD\E\n\s+
             \QOPERATOR 1 <(bigint,integer) ,\E\n\s+
@@ -532,7 +534,9 @@ my %tests = (
             \QOPERATOR 4 >=(bigint,integer) ,\E\n\s+
             \QOPERATOR 5 >(bigint,integer) ,\E\n\s+
             \QFUNCTION 1 (integer, integer) btint4cmp(integer,integer) ,\E\n\s+
+            \QFUNCTION 2 (bigint, bigint) btint8sortsupport(internal) ,\E\n\s+
             \QFUNCTION 2 (integer, integer) btint4sortsupport(internal) ,\E\n\s+
+            \QFUNCTION 4 (bigint, bigint) btequalimage(oid) ,\E\n\s+
             \QFUNCTION 4 (integer, integer) btequalimage(oid);\E
             /xm,
         like =>
@@ -1558,6 +1562,8 @@ my %tests = (
                          FUNCTION 1 btint8cmp(bigint,bigint),
                          FUNCTION 2 btint8sortsupport(internal),
                          FUNCTION 4 btequalimage(oid);',
+        # note: it's correct that btint8sortsupport and btequalimage
+        # are NOT included here (they're optional support functions):
         regexp => qr/^
             \QCREATE OPERATOR CLASS dump_test.op_class\E\n\s+
             \QFOR TYPE bigint USING btree FAMILY dump_test.op_family AS\E\n\s+
@@ -1566,9 +1572,7 @@ my %tests = (
             \QOPERATOR 3 =(bigint,bigint) ,\E\n\s+
             \QOPERATOR 4 >=(bigint,bigint) ,\E\n\s+
             \QOPERATOR 5 >(bigint,bigint) ,\E\n\s+
-            \QFUNCTION 1 (bigint, bigint) btint8cmp(bigint,bigint) ,\E\n\s+
-            \QFUNCTION 2 (bigint, bigint) btint8sortsupport(internal) ,\E\n\s+
-            \QFUNCTION 4 (bigint, bigint) btequalimage(oid);\E
+            \QFUNCTION 1 (bigint, bigint) btint8cmp(bigint,bigint);\E
             /xm,
         like =>
           { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
diff --git a/src/include/access/amapi.h b/src/include/access/amapi.h
index 4325faa..6538fc8 100644
--- a/src/include/access/amapi.h
+++ b/src/include/access/amapi.h
@@ -54,6 +54,42 @@ typedef enum IndexAMProperty
     AMPROP_CAN_INCLUDE
 } IndexAMProperty;

+/*
+ * We use lists of this struct type to keep track of both operators and
+ * support functions while building or adding to an opclass or opfamily.
+ * amcheckmembers functions receive lists of these structs, and are allowed
+ * to alter their "ref" fields.
+ *
+ * The "ref" fields define how the pg_amop or pg_amproc entry should depend
+ * on the associated objects (that is, which dependency type to use, and
+ * which opclass or opfamily it should depend on).
+ *
+ * If ref_is_hard is true, the entry will have a NORMAL dependency on the
+ * operator or support func, and an INTERNAL dependency on the opclass or
+ * opfamily.  This forces the opclass or opfamily to be dropped if the
+ * operator or support func is dropped, and requires the CASCADE option
+ * to do so.  Nor will ALTER OPERATOR FAMILY DROP be allowed.  This is
+ * the right behavior for objects that are essential to an opclass.
+ *
+ * If ref_is_hard is false, the entry will have an AUTO dependency on the
+ * operator or support func, and also an AUTO dependency on the opclass or
+ * opfamily.  This allows ALTER OPERATOR FAMILY DROP, and causes that to
+ * happen automatically if the operator or support func is dropped.  This
+ * is the right behavior for inessential ("loose") objects.
+ */
+typedef struct OpFamilyMember
+{
+    bool        is_func;        /* is this an operator, or support func? */
+    Oid            object;            /* operator or support func's OID */
+    int            number;            /* strategy or support func number */
+    Oid            lefttype;        /* lefttype */
+    Oid            righttype;        /* righttype */
+    Oid            sortfamily;        /* ordering operator's sort opfamily, or 0 */
+    bool        ref_is_hard;    /* hard or soft dependency? */
+    bool        ref_is_family;    /* is dependency on opclass or opfamily? */
+    Oid            refobjid;        /* OID of opclass or opfamily */
+} OpFamilyMember;
+

 /*
  * Callback function signatures --- see indexam.sgml for more info.
@@ -114,6 +150,12 @@ typedef char *(*ambuildphasename_function) (int64 phasenum);
 /* validate definition of an opclass for this AM */
 typedef bool (*amvalidate_function) (Oid opclassoid);

+/* validate operators and support functions to be added to an opclass/family */
+typedef void (*amcheckmembers_function) (Oid opfamilyoid,
+                                         Oid opclassoid,
+                                         List *operators,
+                                         List *functions);
+
 /* prepare for index scan */
 typedef IndexScanDesc (*ambeginscan_function) (Relation indexRelation,
                                                int nkeys,
@@ -224,6 +266,7 @@ typedef struct IndexAmRoutine
     amproperty_function amproperty; /* can be NULL */
     ambuildphasename_function ambuildphasename; /* can be NULL */
     amvalidate_function amvalidate;
+    amcheckmembers_function amcheckmembers; /* can be NULL */
     ambeginscan_function ambeginscan;
     amrescan_function amrescan;
     amgettuple_function amgettuple; /* can be NULL */
diff --git a/src/include/access/amvalidate.h b/src/include/access/amvalidate.h
index f3a0e52..670991d 100644
--- a/src/include/access/amvalidate.h
+++ b/src/include/access/amvalidate.h
@@ -1,7 +1,8 @@
 /*-------------------------------------------------------------------------
  *
  * amvalidate.h
- *      Support routines for index access methods' amvalidate functions.
+ *      Support routines for index access methods' amvalidate and
+ *      amcheckmembers functions.
  *
  * Copyright (c) 2016-2020, PostgreSQL Global Development Group
  *
@@ -32,6 +33,8 @@ extern bool check_amproc_signature(Oid funcid, Oid restype, bool exact,
 extern bool check_amoptsproc_signature(Oid funcid);
 extern bool check_amop_signature(Oid opno, Oid restype,
                                  Oid lefttype, Oid righttype);
+extern Oid    opclass_for_family_datatype(Oid amoid, Oid opfamilyoid,
+                                        Oid datatypeoid);
 extern bool opfamily_can_sort_type(Oid opfamilyoid, Oid datatypeoid);

 #endif                            /* AMVALIDATE_H */
diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index 71eeac2..ec8678a 100644
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -407,6 +407,10 @@ extern ItemPointer ginVacuumItemPointers(GinVacuumState *gvs,

 /* ginvalidate.c */
 extern bool ginvalidate(Oid opclassoid);
+extern void gincheckmembers(Oid opfamilyoid,
+                            Oid opclassoid,
+                            List *operators,
+                            List *functions);

 /* ginbulk.c */
 typedef struct GinEntryAccumulator
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 18f2b0d..86cf332 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -462,6 +462,10 @@ extern bool gistcanreturn(Relation index, int attno);

 /* gistvalidate.c */
 extern bool gistvalidate(Oid opclassoid);
+extern void gistcheckmembers(Oid opfamilyoid,
+                             Oid opclassoid,
+                             List *operators,
+                             List *functions);

 /* gistutil.c */

diff --git a/src/include/access/hash.h b/src/include/access/hash.h
index 8cda938..4824b1d 100644
--- a/src/include/access/hash.h
+++ b/src/include/access/hash.h
@@ -379,6 +379,10 @@ extern IndexBulkDeleteResult *hashvacuumcleanup(IndexVacuumInfo *info,
                                                 IndexBulkDeleteResult *stats);
 extern bytea *hashoptions(Datum reloptions, bool validate);
 extern bool hashvalidate(Oid opclassoid);
+extern void hashcheckmembers(Oid opfamilyoid,
+                             Oid opclassoid,
+                             List *operators,
+                             List *functions);

 /* private routines */

diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 5f67fc0..a855fc0 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -1146,6 +1146,10 @@ extern bool _bt_allequalimage(Relation rel, bool debugmessage);
  * prototypes for functions in nbtvalidate.c
  */
 extern bool btvalidate(Oid opclassoid);
+extern void btcheckmembers(Oid opfamilyoid,
+                           Oid opclassoid,
+                           List *operators,
+                           List *functions);

 /*
  * prototypes for functions in nbtsort.c
diff --git a/src/include/access/spgist.h b/src/include/access/spgist.h
index 852d1e2..7ca6168 100644
--- a/src/include/access/spgist.h
+++ b/src/include/access/spgist.h
@@ -220,5 +220,9 @@ extern IndexBulkDeleteResult *spgvacuumcleanup(IndexVacuumInfo *info,

 /* spgvalidate.c */
 extern bool spgvalidate(Oid opclassoid);
+extern void spgcheckmembers(Oid opfamilyoid,
+                            Oid opclassoid,
+                            List *operators,
+                            List *functions);

 #endif                            /* SPGIST_H */
diff --git a/src/include/catalog/opfam_internal.h b/src/include/catalog/opfam_internal.h
deleted file mode 100644
index d63bd9f..0000000
--- a/src/include/catalog/opfam_internal.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * opfam_internal.h
- *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * src/include/catalog/opfam_internal.h
- *
- *-------------------------------------------------------------------------
- */
-#ifndef OPFAM_INTERNAL_H
-#define OPFAM_INTERNAL_H
-
-/*
- * We use lists of this struct type to keep track of both operators and
- * procedures while building or adding to an opfamily.
- */
-typedef struct
-{
-    Oid            object;            /* operator or support proc's OID */
-    int            number;            /* strategy or support proc number */
-    Oid            lefttype;        /* lefttype */
-    Oid            righttype;        /* righttype */
-    Oid            sortfamily;        /* ordering operator's sort opfamily, or 0 */
-} OpFamilyMember;
-
-#endif                            /* OPFAM_INTERNAL_H */