Add unique index on pg_cast.oid, and document pg_cast table.

This commit is contained in:
Peter Eisentraut 2002-07-22 20:23:19 +00:00
parent a7ffd69d4c
commit e9c013f4bd
4 changed files with 86 additions and 15 deletions

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@ -1,6 +1,6 @@
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
$Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.45 2002/07/12 18:43:12 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.46 2002/07/22 20:23:19 petere Exp $
-->
<chapter id="catalogs">
@ -66,6 +66,11 @@
<entry>table columns (<quote>attributes</quote>, <quote>fields</quote>)</entry>
</row>
<row>
<entry>pg_cast</entry>
<entry>casts (data type conversions)</entry>
</row>
<row>
<entry>pg_class</entry>
<entry>tables, indexes, sequences (<quote>relations</quote>)</entry>
@ -519,6 +524,65 @@
</sect1>
<sect1 id="catalog-pg-cast">
<title>pg_cast</title>
<para>
<structname>pg_cast</structname> stores data type conversion paths
defined with <command>CREATE CAST</command> plus the built-in
conversions.
</para>
<table>
<title>pg_cast Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>castsource</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>OID of the source data type</entry>
</row>
<row>
<entry>casttarget</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>OID of the target data type</entry>
</row>
<row>
<entry>castfunc</entry>
<entry><type>oid</type></entry>
<entry>pg_proc.oid</entry>
<entry>
The OID of the function to use to perform this cast. A 0 is
stored if the data types are binary compatible (that is, no
function is needed to perform the cast).
</entry>
</row>
<row>
<entry>castimplicit</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>Indication whether this cast can be invoked implicitly</entry>
</row>
</tbody>
</tgroup>
</table>
</sect1>
<sect1 id="catalog-pg-class">
<title>pg_class</title>

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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.98 2002/07/18 23:11:27 petere Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.99 2002/07/22 20:23:19 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -44,7 +44,7 @@ char *Name_pg_attr_indices[Num_pg_attr_indices] =
char *Name_pg_attrdef_indices[Num_pg_attrdef_indices] =
{AttrDefaultIndex, AttrDefaultOidIndex};
char *Name_pg_cast_indices[Num_pg_cast_indices] =
{CastSourceTargetIndex};
{CastOidIndex, CastSourceTargetIndex};
char *Name_pg_class_indices[Num_pg_class_indices] =
{ClassNameNspIndex, ClassOidIndex};
char *Name_pg_constraint_indices[Num_pg_constraint_indices] =

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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/functioncmds.c,v 1.11 2002/07/20 05:37:45 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/functioncmds.c,v 1.12 2002/07/22 20:23:19 petere Exp $
*
* DESCRIPTION
* These routines take the parse tree and pick out the
@ -31,6 +31,7 @@
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/dependency.h"
@ -693,7 +694,7 @@ CreateCast(CreateCastStmt *stmt)
if (procstruct->proisagg)
elog(ERROR, "cast function must not be an aggregate function");
if (procstruct->proretset)
elog(ERROR, "cast function must be not return a set");
elog(ERROR, "cast function must not return a set");
ReleaseSysCache(tuple);
}
@ -727,7 +728,7 @@ CreateCast(CreateCastStmt *stmt)
CatalogCloseIndices(Num_pg_cast_indices, idescs);
}
myself.classId = get_system_catalog_relid(CastRelationName);
myself.classId = RelationGetRelid(relation);
myself.objectId = HeapTupleGetOid(tuple);
myself.objectSubId = 0;
@ -819,21 +820,25 @@ DropCast(DropCastStmt *stmt)
void
DropCastById(Oid castOid)
{
Relation relation;
Relation relation,
index;
ScanKeyData scankey;
HeapScanDesc scan;
IndexScanDesc scan;
HeapTuple tuple;
relation = heap_openr(CastRelationName, RowExclusiveLock);
index = index_openr(CastOidIndex);
ScanKeyEntryInitialize(&scankey, 0x0,
ObjectIdAttributeNumber, F_OIDEQ,
ObjectIdGetDatum(castOid));
scan = heap_beginscan(relation, SnapshotNow, 1, &scankey);
tuple = heap_getnext(scan, ForwardScanDirection);
1, F_OIDEQ, ObjectIdGetDatum(castOid));
scan = index_beginscan(relation, index, SnapshotNow, 1, &scankey);
tuple = index_getnext(scan, ForwardScanDirection);
if (HeapTupleIsValid(tuple))
simple_heap_delete(relation, &tuple->t_self);
else
elog(ERROR, "could not find tuple for cast %u", castOid);
heap_endscan(scan);
index_endscan(scan);
index_close(index);
heap_close(relation, RowExclusiveLock);
}

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@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: indexing.h,v 1.71 2002/07/18 23:11:30 petere Exp $
* $Id: indexing.h,v 1.72 2002/07/22 20:23:19 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -26,7 +26,7 @@
#define Num_pg_amproc_indices 1
#define Num_pg_attr_indices 2
#define Num_pg_attrdef_indices 2
#define Num_pg_cast_indices 1
#define Num_pg_cast_indices 2
#define Num_pg_class_indices 2
#define Num_pg_constraint_indices 3
#define Num_pg_conversion_indices 3
@ -61,6 +61,7 @@
#define AttrDefaultOidIndex "pg_attrdef_oid_index"
#define AttributeRelidNameIndex "pg_attribute_relid_attnam_index"
#define AttributeRelidNumIndex "pg_attribute_relid_attnum_index"
#define CastOidIndex "pg_cast_oid_index"
#define CastSourceTargetIndex "pg_cast_source_target_index"
#define ClassNameNspIndex "pg_class_relname_nsp_index"
#define ClassOidIndex "pg_class_oid_index"
@ -169,6 +170,7 @@ DECLARE_UNIQUE_INDEX(pg_attrdef_adrelid_adnum_index on pg_attrdef using btree(ad
DECLARE_UNIQUE_INDEX(pg_attrdef_oid_index on pg_attrdef using btree(oid oid_ops));
DECLARE_UNIQUE_INDEX(pg_attribute_relid_attnam_index on pg_attribute using btree(attrelid oid_ops, attname name_ops));
DECLARE_UNIQUE_INDEX(pg_attribute_relid_attnum_index on pg_attribute using btree(attrelid oid_ops, attnum int2_ops));
DECLARE_UNIQUE_INDEX(pg_cast_oid_index on pg_cast using btree(oid oid_ops));
DECLARE_UNIQUE_INDEX(pg_cast_source_target_index on pg_cast using btree(castsource oid_ops, casttarget oid_ops));
DECLARE_UNIQUE_INDEX(pg_class_oid_index on pg_class using btree(oid oid_ops));
DECLARE_UNIQUE_INDEX(pg_class_relname_nsp_index on pg_class using btree(relname name_ops, relnamespace oid_ops));