diff options
Diffstat (limited to 'src/backend/utils/cache/lsyscache.c')
| -rw-r--r-- | src/backend/utils/cache/lsyscache.c | 96 |
1 files changed, 95 insertions, 1 deletions
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index fcd9dc2f59..095c5e6a8a 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.95 2003/05/26 00:11:27 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.96 2003/06/22 22:04:54 tgl Exp $ * * NOTES * Eventually, the index information should go through here, too. @@ -16,8 +16,10 @@ #include "postgres.h" #include "miscadmin.h" +#include "access/hash.h" #include "access/tupmacs.h" #include "catalog/pg_amop.h" +#include "catalog/pg_amproc.h" #include "catalog/pg_namespace.h" #include "catalog/pg_opclass.h" #include "catalog/pg_operator.h" @@ -28,6 +30,7 @@ #include "nodes/makefuncs.h" #include "utils/array.h" #include "utils/builtins.h" +#include "utils/catcache.h" #include "utils/datum.h" #include "utils/lsyscache.h" #include "utils/syscache.h" @@ -106,6 +109,72 @@ get_opclass_member(Oid opclass, int16 strategy) return result; } +/* + * get_op_hash_function + * Get the OID of the datatype-specific hash function associated with + * a hashable equality operator. + * + * Returns InvalidOid if no hash function can be found. (This indicates + * that the operator should not have been marked oprcanhash.) + */ +Oid +get_op_hash_function(Oid opno) +{ + CatCList *catlist; + int i; + HeapTuple tuple; + Oid opclass = InvalidOid; + + /* + * Search pg_amop to see if the target operator is registered as the "=" + * operator of any hash opclass. If the operator is registered in + * multiple opclasses, assume we can use the associated hash function + * from any one. + */ + catlist = SearchSysCacheList(AMOPOPID, 1, + ObjectIdGetDatum(opno), + 0, 0, 0); + + for (i = 0; i < catlist->n_members; i++) + { + Form_pg_amop aform; + + tuple = &catlist->members[i]->tuple; + aform = (Form_pg_amop) GETSTRUCT(tuple); + + if (aform->amopstrategy == HTEqualStrategyNumber && + opclass_is_hash(aform->amopclaid)) + { + opclass = aform->amopclaid; + break; + } + } + + ReleaseSysCacheList(catlist); + + if (OidIsValid(opclass)) + { + /* Found a suitable opclass, get its hash support function */ + tuple = SearchSysCache(AMPROCNUM, + ObjectIdGetDatum(opclass), + Int16GetDatum(HASHPROC), + 0, 0); + if (HeapTupleIsValid(tuple)) + { + Form_pg_amproc aform = (Form_pg_amproc) GETSTRUCT(tuple); + RegProcedure result; + + result = aform->amproc; + ReleaseSysCache(tuple); + Assert(RegProcedureIsValid(result)); + return result; + } + } + + /* Didn't find a match... */ + return InvalidOid; +} + /* ---------- ATTRIBUTE CACHES ---------- */ @@ -284,6 +353,31 @@ opclass_is_btree(Oid opclass) return result; } +/* + * opclass_is_hash + * + * Returns TRUE iff the specified opclass is associated with the + * hash index access method. + */ +bool +opclass_is_hash(Oid opclass) +{ + HeapTuple tp; + Form_pg_opclass cla_tup; + bool result; + + tp = SearchSysCache(CLAOID, + ObjectIdGetDatum(opclass), + 0, 0, 0); + if (!HeapTupleIsValid(tp)) + elog(ERROR, "cache lookup failed for opclass %u", opclass); + cla_tup = (Form_pg_opclass) GETSTRUCT(tp); + + result = (cla_tup->opcamid == HASH_AM_OID); + ReleaseSysCache(tp); + return result; +} + /* ---------- OPERATOR CACHE ---------- */ /* |