1 /*-------------------------------------------------------------------------
4 * POSTGRES relation descriptor (a/k/a relcache entry) definitions.
7 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $Id: rel.h,v 1.48 2001/06/19 12:03:41 momjian Exp $
12 *-------------------------------------------------------------------------
17 #include "access/strat.h"
18 #include "access/tupdesc.h"
19 #include "catalog/pg_am.h"
20 #include "catalog/pg_class.h"
21 #include "rewrite/prs2lock.h"
22 #include "storage/relfilenode.h"
23 #include "storage/fd.h"
25 /* added to prevent circular dependency. bjm 1999/11/15 */
26 extern char *get_temp_rel_by_physicalname(const char *relname);
29 * LockRelId and LockInfo really belong to lmgr.h, but it's more convenient
30 * to declare them here so we can have a LockInfoData field in a Relation.
33 typedef struct LockRelId
35 Oid relId; /* a relation identifier */
36 Oid dbId; /* a database identifier */
39 typedef struct LockInfoData
44 typedef LockInfoData *LockInfo;
47 * Likewise, this struct really belongs to trigger.h, but for convenience
50 typedef struct Trigger
61 int16 tgattr[FUNC_MAX_ARGS];
65 typedef struct TriggerDesc
68 * Index data to identify which triggers are which. Since each trigger
69 * can appear in more than one class, for each class we provide a list
70 * of integer indexes into the triggers array.
72 #define TRIGGER_NUM_EVENT_CLASSES 4
74 uint16 n_before_statement[TRIGGER_NUM_EVENT_CLASSES];
75 uint16 n_before_row[TRIGGER_NUM_EVENT_CLASSES];
76 uint16 n_after_row[TRIGGER_NUM_EVENT_CLASSES];
77 uint16 n_after_statement[TRIGGER_NUM_EVENT_CLASSES];
78 int *tg_before_statement[TRIGGER_NUM_EVENT_CLASSES];
79 int *tg_before_row[TRIGGER_NUM_EVENT_CLASSES];
80 int *tg_after_row[TRIGGER_NUM_EVENT_CLASSES];
81 int *tg_after_statement[TRIGGER_NUM_EVENT_CLASSES];
83 /* The actual array of triggers is here */
89 * Here are the contents of a relation cache entry.
92 typedef struct RelationData
94 File rd_fd; /* open file descriptor, or -1 if none */
95 RelFileNode rd_node; /* relation file node */
96 int rd_nblocks; /* number of blocks in rel */
97 uint16 rd_refcnt; /* reference count */
98 bool rd_myxactonly; /* rel uses the local buffer mgr */
99 bool rd_isnailed; /* rel is nailed in cache */
100 bool rd_indexfound; /* true if rd_indexlist is valid */
101 bool rd_uniqueindex; /* true if rel is a UNIQUE index */
102 Form_pg_am rd_am; /* AM tuple */
103 Form_pg_class rd_rel; /* RELATION tuple */
104 Oid rd_id; /* relation's object id */
105 List *rd_indexlist; /* list of OIDs of indexes on relation */
106 LockInfoData rd_lockInfo; /* lock mgr's info for locking relation */
107 TupleDesc rd_att; /* tuple descriptor */
108 RuleLock *rd_rules; /* rewrite rules */
109 MemoryContext rd_rulescxt; /* private memory cxt for rd_rules, if any */
110 IndexStrategy rd_istrat; /* info needed if rel is an index */
111 RegProcedure *rd_support;
112 TriggerDesc *trigdesc; /* Trigger info, or NULL if rel has none */
115 typedef RelationData *Relation;
119 * RelationPtr is used in the executor to support index scans
120 * where we have to keep track of several index relations in an
121 * array. -cim 9/10/89
124 typedef Relation *RelationPtr;
129 * True iff relation descriptor is valid.
131 #define RelationIsValid(relation) PointerIsValid(relation)
133 #define InvalidRelation ((Relation) NULL)
136 * RelationHasReferenceCountZero
137 * True iff relation reference count is zero.
140 * Assumes relation descriptor is valid.
142 #define RelationHasReferenceCountZero(relation) \
143 ((bool)((relation)->rd_refcnt == 0))
146 * RelationSetReferenceCount
147 * Sets relation reference count.
149 #define RelationSetReferenceCount(relation,count) \
150 ((relation)->rd_refcnt = (count))
153 * RelationIncrementReferenceCount
154 * Increments relation reference count.
156 #define RelationIncrementReferenceCount(relation) \
157 ((relation)->rd_refcnt += 1)
160 * RelationDecrementReferenceCount
161 * Decrements relation reference count.
163 #define RelationDecrementReferenceCount(relation) \
164 (AssertMacro((relation)->rd_refcnt > 0), \
165 (relation)->rd_refcnt -= 1)
169 * Returns pg_class tuple for a relation.
172 * Assumes relation descriptor is valid.
174 #define RelationGetForm(relation) ((relation)->rd_rel)
179 * returns the OID of the relation
181 #define RelationGetRelid(relation) ((relation)->rd_id)
186 * Returns the open file descriptor for the rel
188 #define RelationGetFile(relation) ((relation)->rd_fd)
191 * RelationGetNumberOfAttributes
193 * Returns the number of attributes.
195 #define RelationGetNumberOfAttributes(relation) ((relation)->rd_rel->relnatts)
199 * Returns tuple descriptor for a relation.
201 #define RelationGetDescr(relation) ((relation)->rd_att)
204 * RelationGetIndexStrategy
205 * Returns index strategy for a relation.
208 * Assumes relation descriptor is valid.
209 * Assumes relation descriptor is for an index relation.
211 #define RelationGetIndexStrategy(relation) ((relation)->rd_istrat)
214 * Routines in utils/cache/rel.c
216 extern void RelationSetIndexSupport(Relation relation,
217 IndexStrategy strategy,
218 RegProcedure *support);
221 * Handle temp relations
223 #define PG_TEMP_REL_PREFIX "pg_temp"
225 #define is_temp_relname(relname) \
226 (strncmp(relname, PG_TEMP_REL_PREFIX, strlen(PG_TEMP_REL_PREFIX)) == 0)
229 * RelationGetPhysicalRelationName
231 * Returns the rel's physical name, ie, the name appearing in pg_class.
233 * While this name is unique across all rels in the database, it is not
234 * necessarily useful for accessing the rel, since a temp table of the
235 * same name might mask the rel. It is useful mainly for determining if
236 * the rel is a shared system rel or not.
238 * The macro is rather unfortunately named, since the pg_class name no longer
239 * has anything to do with the file name used for physical storage of the rel.
241 #define RelationGetPhysicalRelationName(relation) \
242 (NameStr((relation)->rd_rel->relname))
245 * RelationGetRelationName
247 * Returns the relation's logical name (as seen by the user).
249 * If the rel is a temp rel, the temp name will be returned. Therefore,
250 * this name is not unique. But it is the name to use in heap_openr(),
253 #define RelationGetRelationName(relation) \
255 !is_temp_relname(relation) \
257 RelationGetPhysicalRelationName(relation) \
259 get_temp_rel_by_physicalname( \
260 RelationGetPhysicalRelationName(relation)) \