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Restructure operator classes to allow improved handling of cross-data-type

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cases.  Operator classes now exist within "operator families".  While most
families are equivalent to a single class, related classes can be grouped
into one family to represent the fact that they are semantically compatible.
Cross-type operators are now naturally adjunct parts of a family, without
having to wedge them into a particular opclass as we had done originally.

This commit restructures the catalogs and cleans up enough of the fallout so
that everything still works at least as well as before, but most of the work
needed to actually improve the planner's behavior will come later.  Also,
there are not yet CREATE/DROP/ALTER OPERATOR FAMILY commands; the only way
to create a new family right now is to allow CREATE OPERATOR CLASS to make
one by default.  I owe some more documentation work, too.  But that can all
be done in smaller pieces once this infrastructure is in place.
This commit is contained in:
Tom Lane
2006-12-23 00:43:13 +00:00
parent d31ccb6c3e
commit a78fcfb512
76 changed files with 4753 additions and 4100 deletions
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28
src/backend/access/hash/hashfunc.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashfunc.c,v 1.48 2006/10/04 00:29:48 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashfunc.c,v 1.49 2006/12/23 00:43:08 tgl Exp $
*
* NOTES
* These functions are stored in pg_amproc. For each operator class
@@ -46,11 +46,11 @@ hashint8(PG_FUNCTION_ARGS)
{
/*
* The idea here is to produce a hash value compatible with the values
* produced by hashint4 and hashint2 for logically equivalent inputs; this
* is necessary if we ever hope to support cross-type hash joins across
* these input types. Since all three types are signed, we can xor the
* high half of the int8 value if the sign is positive, or the complement
* of the high half when the sign is negative.
* produced by hashint4 and hashint2 for logically equal inputs; this is
* necessary to support cross-type hash joins across these input types.
* Since all three types are signed, we can xor the high half of the int8
* value if the sign is positive, or the complement of the high half when
* the sign is negative.
*/
#ifndef INT64_IS_BUSTED
int64 val = PG_GETARG_INT64(0);
@@ -76,16 +76,26 @@ Datum
hashfloat4(PG_FUNCTION_ARGS)
{
float4 key = PG_GETARG_FLOAT4(0);
float8 key8;
/*
* On IEEE-float machines, minus zero and zero have different bit patterns
* but should compare as equal. We must ensure that they have the same
* hash value, which is most easily done this way:
* hash value, which is most reliably done this way:
*/
if (key == (float4) 0)
PG_RETURN_UINT32(0);
return hash_any((unsigned char *) &key, sizeof(key));
/*
* To support cross-type hashing of float8 and float4, we want to return
* the same hash value hashfloat8 would produce for an equal float8 value.
* So, widen the value to float8 and hash that. (We must do this rather
* than have hashfloat8 try to narrow its value to float4; that could
* fail on overflow.)
*/
key8 = key;
return hash_any((unsigned char *) &key8, sizeof(key8));
}
Datum
@@ -96,7 +106,7 @@ hashfloat8(PG_FUNCTION_ARGS)
/*
* On IEEE-float machines, minus zero and zero have different bit patterns
* but should compare as equal. We must ensure that they have the same
* hash value, which is most easily done this way:
* hash value, which is most reliably done this way:
*/
if (key == (float8) 0)
PG_RETURN_UINT32(0);