Rename amcancrosscompare

After more discussion about commit ce62f2f2a0a, rename the index AM
property amcancrosscompare to two separate properties
amconsistentequality and amconsistentordering.  Also improve the
documentation and update some comments that were previously missed.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/E1tngY6-0000UL-2n%40gemulon.postgresql.org
This commit is contained in:
Peter Eisentraut 2025-03-07 10:51:53 +01:00
parent 6da469bada
commit af4002b381
12 changed files with 41 additions and 26 deletions

View File

@ -110,7 +110,8 @@ blhandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;

View File

@ -105,8 +105,10 @@ typedef struct IndexAmRoutine
bool amcanorderbyop;
/* does AM support hashing using API consistent with the hash AM? */
bool amcanhash;
/* does AM support cross-type comparisons? */
bool amcancrosscompare;
/* do operators within an opfamily have consistent equality semantics? */
bool amconsistentequality;
/* do operators within an opfamily have consistent ordering semantics? */
bool amconsistentordering;
/* does AM support backward scanning? */
bool amcanbackward;
/* does AM support UNIQUE indexes? */

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@ -257,7 +257,8 @@ brinhandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;

View File

@ -45,7 +45,8 @@ ginhandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;

View File

@ -66,7 +66,8 @@ gisthandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = true;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;

View File

@ -65,7 +65,8 @@ hashhandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = true;
amroutine->amcancrosscompare = true;
amroutine->amconsistentequality = true;
amroutine->amconsistentequality = false;
amroutine->amcanbackward = true;
amroutine->amcanunique = false;
amroutine->amcanmulticol = false;

View File

@ -108,7 +108,8 @@ bthandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = true;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = true;
amroutine->amconsistentequality = true;
amroutine->amconsistentordering = true;
amroutine->amcanbackward = true;
amroutine->amcanunique = true;
amroutine->amcanmulticol = true;

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@ -51,7 +51,8 @@ spghandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = true;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = false;

View File

@ -1083,9 +1083,10 @@ query_supports_distinctness(Query *query)
* the values are distinct. (Note: the opids entries could be cross-type
* operators, and thus not exactly the equality operators that the subquery
* would use itself. We use equality_ops_are_compatible() to check
* compatibility. That looks at btree or hash opfamily membership, and so
* should give trustworthy answers for all operators that we might need
* to deal with here.)
* compatibility. That looks at opfamily membership for index AMs that have
* declared that they support consistent equality semantics within an
* opfamily, and so should give trustworthy answers for all operators that we
* might need to deal with here.)
*/
bool
query_is_distinct_for(Query *query, List *colnos, List *opids)

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@ -690,10 +690,11 @@ get_op_btree_interpretation(Oid opno)
* semantics.
*
* This is trivially true if they are the same operator. Otherwise,
* we look to see if they can be found in the same btree or hash opfamily.
* Either finding allows us to assume that they have compatible notions
* of equality. (The reason we need to do these pushups is that one might
* be a cross-type operator; for instance int24eq vs int4eq.)
* Otherwise, we look to see if they both belong to an opfamily that
* guarantees compatible semantics for equality. Either finding allows us to
* assume that they have compatible notions of equality. (The reason we need
* to do these pushups is that one might be a cross-type operator; for
* instance int24eq vs int4eq.)
*/
bool
equality_ops_are_compatible(Oid opno1, Oid opno2)
@ -718,7 +719,7 @@ equality_ops_are_compatible(Oid opno1, Oid opno2)
Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);
IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(op_form->amopmethod, false);
if (amroutine->amcancrosscompare)
if (amroutine->amconsistentequality)
{
if (op_in_opfamily(opno2, op_form->amopfamily))
{
@ -738,12 +739,13 @@ equality_ops_are_compatible(Oid opno1, Oid opno2)
* Return true if the two given comparison operators have compatible
* semantics.
*
* This is trivially true if they are the same operator. Otherwise,
* we look to see if they can be found in the same btree opfamily.
* For example, '<' and '>=' ops match if they belong to the same family.
* This is trivially true if they are the same operator. Otherwise, we look
* to see if they both belong to an opfamily that guarantees compatible
* semantics for ordering. (For example, for btree, '<' and '>=' ops match if
* they belong to the same family.)
*
* (This is identical to equality_ops_are_compatible(), except that we
* don't bother to examine hash opclasses.)
* (This is identical to equality_ops_are_compatible(), except that we check
* amcanorder plus amconsistentordering instead of amconsistentequality.)
*/
bool
comparison_ops_are_compatible(Oid opno1, Oid opno2)
@ -768,7 +770,7 @@ comparison_ops_are_compatible(Oid opno1, Oid opno2)
Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);
IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(op_form->amopmethod, false);
if (amroutine->amcanorder && amroutine->amcancrosscompare)
if (amroutine->amcanorder && amroutine->amconsistentordering)
{
if (op_in_opfamily(opno2, op_form->amopfamily))
{

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@ -245,8 +245,10 @@ typedef struct IndexAmRoutine
bool amcanorderbyop;
/* does AM support hashing using API consistent with the hash AM? */
bool amcanhash;
/* does AM support cross-type comparisons? */
bool amcancrosscompare;
/* do operators within an opfamily have consistent equality semantics? */
bool amconsistentequality;
/* do operators within an opfamily have consistent ordering semantics? */
bool amconsistentordering;
/* does AM support backward scanning? */
bool amcanbackward;
/* does AM support UNIQUE indexes? */

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@ -283,7 +283,8 @@ dihandler(PG_FUNCTION_ARGS)
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanhash = false;
amroutine->amcancrosscompare = false;
amroutine->amconsistentequality = false;
amroutine->amconsistentordering = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = false;