PostgreSQL/src/include/utils/rel.h

/*-------------------------------------------------------------------------
 *
 * rel.h
 *	  POSTGRES relation descriptor (a/k/a relcache entry) definitions.
 *
 *
 * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.91 2006/07/03 22:45:41 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef REL_H
#define REL_H

#include "access/tupdesc.h"
#include "catalog/pg_am.h"
#include "catalog/pg_class.h"
#include "catalog/pg_index.h"
#include "fmgr.h"
#include "rewrite/prs2lock.h"
#include "storage/block.h"
#include "storage/relfilenode.h"


/*
 * LockRelId and LockInfo really belong to lmgr.h, but it's more convenient
 * to declare them here so we can have a LockInfoData field in a Relation.
 */

typedef struct LockRelId
{
	Oid			relId;			/* a relation identifier */
	Oid			dbId;			/* a database identifier */
} LockRelId;

typedef struct LockInfoData
{
	LockRelId	lockRelId;
} LockInfoData;

typedef LockInfoData *LockInfo;

/*
 * Likewise, this struct really belongs to trigger.h, but for convenience
 * we put it here.
 */
typedef struct Trigger
{
	Oid			tgoid;			/* OID of trigger (pg_trigger row) */
	/* Remaining fields are copied from pg_trigger, see pg_trigger.h */
	char	   *tgname;
	Oid			tgfoid;
	int16		tgtype;
	bool		tgenabled;
	bool		tgisconstraint;
	Oid			tgconstrrelid;
	bool		tgdeferrable;
	bool		tginitdeferred;
	int16		tgnargs;
	int16		tgnattr;
	int16	   *tgattr;
	char	  **tgargs;
} Trigger;

typedef struct TriggerDesc
{
	/*
	 * Index data to identify which triggers are which.  Since each trigger
	 * can appear in more than one class, for each class we provide a list of
	 * integer indexes into the triggers array.
	 */
#define TRIGGER_NUM_EVENT_CLASSES  3

	uint16		n_before_statement[TRIGGER_NUM_EVENT_CLASSES];
	uint16		n_before_row[TRIGGER_NUM_EVENT_CLASSES];
	uint16		n_after_row[TRIGGER_NUM_EVENT_CLASSES];
	uint16		n_after_statement[TRIGGER_NUM_EVENT_CLASSES];
	int		   *tg_before_statement[TRIGGER_NUM_EVENT_CLASSES];
	int		   *tg_before_row[TRIGGER_NUM_EVENT_CLASSES];
	int		   *tg_after_row[TRIGGER_NUM_EVENT_CLASSES];
	int		   *tg_after_statement[TRIGGER_NUM_EVENT_CLASSES];

	/* The actual array of triggers is here */
	Trigger    *triggers;
	int			numtriggers;
} TriggerDesc;


/*
 * Same for the statistics collector data in Relation and scan data.
 */
typedef struct PgStat_Info
{
	void	   *tabentry;
} PgStat_Info;


/*
 * Cached lookup information for the index access method functions defined
 * by the pg_am row associated with an index relation.
 */
typedef struct RelationAmInfo
{
	FmgrInfo	aminsert;
	FmgrInfo	ambeginscan;
	FmgrInfo	amgettuple;
	FmgrInfo	amgetmulti;
	FmgrInfo	amrescan;
	FmgrInfo	amendscan;
	FmgrInfo	ammarkpos;
	FmgrInfo	amrestrpos;
	FmgrInfo	ambuild;
	FmgrInfo	ambulkdelete;
	FmgrInfo	amvacuumcleanup;
	FmgrInfo	amcostestimate;
	FmgrInfo	amoptions;
} RelationAmInfo;


/*
 * Here are the contents of a relation cache entry.
 */

typedef struct RelationData
{
	RelFileNode rd_node;		/* relation physical identifier */
	/* use "struct" here to avoid needing to include smgr.h: */
	struct SMgrRelationData *rd_smgr;	/* cached file handle, or NULL */
	BlockNumber rd_targblock;	/* current insertion target block, or
								 * InvalidBlockNumber */
	int			rd_refcnt;		/* reference count */
	bool		rd_istemp;		/* rel uses the local buffer mgr */
	bool		rd_isnailed;	/* rel is nailed in cache */
	bool		rd_isvalid;		/* relcache entry is valid */
	char		rd_indexvalid;	/* state of rd_indexlist: 0 = not valid, 1 =
								 * valid, 2 = temporarily forced */
	SubTransactionId rd_createSubid;	/* rel was created in current xact */

	/*
	 * rd_createSubid is the ID of the highest subtransaction the rel has
	 * survived into; or zero if the rel was not created in the current top
	 * transaction.  This should be relied on only for optimization purposes;
	 * it is possible for new-ness to be "forgotten" (eg, after CLUSTER).
	 */
	Form_pg_class rd_rel;		/* RELATION tuple */
	TupleDesc	rd_att;			/* tuple descriptor */
	Oid			rd_id;			/* relation's object id */
	List	   *rd_indexlist;	/* list of OIDs of indexes on relation */
	Oid			rd_oidindex;	/* OID of unique index on OID, if any */
	LockInfoData rd_lockInfo;	/* lock mgr's info for locking relation */
	RuleLock   *rd_rules;		/* rewrite rules */
	MemoryContext rd_rulescxt;	/* private memory cxt for rd_rules, if any */
	TriggerDesc *trigdesc;		/* Trigger info, or NULL if rel has none */

	/*
	 * rd_options is set whenever rd_rel is loaded into the relcache entry.
	 * Note that you can NOT look into rd_rel for this data.  NULL means
	 * "use defaults".
	 */
	bytea	   *rd_options;		/* parsed pg_class.reloptions */

	/* These are non-NULL only for an index relation: */
	Form_pg_index rd_index;		/* pg_index tuple describing this index */
	struct HeapTupleData *rd_indextuple;		/* all of pg_index tuple */
	/* "struct HeapTupleData *" avoids need to include htup.h here	*/
	oidvector  *rd_indclass;	/* extracted pointer to rd_index field */
	Form_pg_am	rd_am;			/* pg_am tuple for index's AM */

	/*
	 * index access support info (used only for an index relation)
	 *
	 * Note: only default operators and support procs for each opclass are
	 * cached, namely those with subtype zero.	The arrays are indexed by
	 * strategy or support number, which is a sufficient identifier given that
	 * restriction.
	 *
	 * Note: rd_amcache is available for index AMs to cache private data about
	 * an index.  This must be just a cache since it may get reset at any time
	 * (in particular, it will get reset by a relcache inval message for the
	 * index).  If used, it must point to a single memory chunk palloc'd in
	 * rd_indexcxt.  A relcache reset will include freeing that chunk and
	 * setting rd_amcache = NULL.
	 */
	MemoryContext rd_indexcxt;	/* private memory cxt for this stuff */
	RelationAmInfo *rd_aminfo;	/* lookup info for funcs found in pg_am */
	Oid		   *rd_operator;	/* OIDs of index operators */
	RegProcedure *rd_support;	/* OIDs of support procedures */
	FmgrInfo   *rd_supportinfo; /* lookup info for support procedures */
	List	   *rd_indexprs;	/* index expression trees, if any */
	List	   *rd_indpred;		/* index predicate tree, if any */
	void	   *rd_amcache;		/* available for use by index AM */

	/* statistics collection area */
	PgStat_Info pgstat_info;
} RelationData;

typedef RelationData *Relation;


/* ----------------
 *		RelationPtr is used in the executor to support index scans
 *		where we have to keep track of several index relations in an
 *		array.	-cim 9/10/89
 * ----------------
 */
typedef Relation *RelationPtr;


/*
 * StdRdOptions
 *		Standard contents of rd_options for heaps and generic indexes.
 *
 * RelationGetFillFactor() and RelationGetTargetPageFreeSpace() can only
 * be applied to relations that use this format or a superset for
 * private options data.
 */
typedef struct StdRdOptions
{
	int32	vl_len;				/* required to be a bytea */
	int		fillfactor;			/* page fill factor in percent (0..100) */
} StdRdOptions;

#define HEAP_MIN_FILLFACTOR			10
#define HEAP_DEFAULT_FILLFACTOR		100

/*
 * RelationGetFillFactor
 *		Returns the relation's fillfactor.  Note multiple eval of argument!
 */
#define RelationGetFillFactor(relation, defaultff) \
	((relation)->rd_options ? \
	 ((StdRdOptions *) (relation)->rd_options)->fillfactor : (defaultff))

/*
 * RelationGetTargetPageUsage
 *		Returns the relation's desired space usage per page in bytes.
 */
#define RelationGetTargetPageUsage(relation, defaultff) \
	(BLCKSZ * RelationGetFillFactor(relation, defaultff) / 100)

/*
 * RelationGetTargetPageFreeSpace
 *		Returns the relation's desired freespace per page in bytes.
 */
#define RelationGetTargetPageFreeSpace(relation, defaultff) \
	(BLCKSZ * (100 - RelationGetFillFactor(relation, defaultff)) / 100)

/*
 * RelationIsValid
 *		True iff relation descriptor is valid.
 */
#define RelationIsValid(relation) PointerIsValid(relation)

#define InvalidRelation ((Relation) NULL)

/*
 * RelationHasReferenceCountZero
 *		True iff relation reference count is zero.
 *
 * Note:
 *		Assumes relation descriptor is valid.
 */
#define RelationHasReferenceCountZero(relation) \
		((bool)((relation)->rd_refcnt == 0))

/*
 * RelationGetForm
 *		Returns pg_class tuple for a relation.
 *
 * Note:
 *		Assumes relation descriptor is valid.
 */
#define RelationGetForm(relation) ((relation)->rd_rel)

/*
 * RelationGetRelid
 *		Returns the OID of the relation
 */
#define RelationGetRelid(relation) ((relation)->rd_id)

/*
 * RelationGetNumberOfAttributes
 *		Returns the number of attributes in a relation.
 */
#define RelationGetNumberOfAttributes(relation) ((relation)->rd_rel->relnatts)

/*
 * RelationGetDescr
 *		Returns tuple descriptor for a relation.
 */
#define RelationGetDescr(relation) ((relation)->rd_att)

/*
 * RelationGetRelationName
 *		Returns the rel's name.
 *
 * Note that the name is only unique within the containing namespace.
 */
#define RelationGetRelationName(relation) \
	(NameStr((relation)->rd_rel->relname))

/*
 * RelationGetNamespace
 *		Returns the rel's namespace OID.
 */
#define RelationGetNamespace(relation) \
	((relation)->rd_rel->relnamespace)

/*
 * RelationOpenSmgr
 *		Open the relation at the smgr level, if not already done.
 */
#define RelationOpenSmgr(relation) \
	do { \
		if ((relation)->rd_smgr == NULL) \
			smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node)); \
	} while (0)

/*
 * RelationCloseSmgr
 *		Close the relation at the smgr level, if not already done.
 *
 * Note: smgrclose should unhook from owner pointer, hence the Assert.
 */
#define RelationCloseSmgr(relation) \
	do { \
		if ((relation)->rd_smgr != NULL) \
		{ \
			smgrclose((relation)->rd_smgr); \
			Assert((relation)->rd_smgr == NULL); \
		} \
	} while (0)

/*
 * RELATION_IS_LOCAL
 *		If a rel is either temp or newly created in the current transaction,
 *		it can be assumed to be visible only to the current backend.
 *
 * Beware of multiple eval of argument
 */
#define RELATION_IS_LOCAL(relation) \
	((relation)->rd_istemp || \
	 (relation)->rd_createSubid != InvalidSubTransactionId)

/* routines in utils/cache/relcache.c */
extern void RelationIncrementReferenceCount(Relation rel);
extern void RelationDecrementReferenceCount(Relation rel);

#endif   /* REL_H */