rel.h

/*-------------------------------------------------------------------------
 *
 * rel.h
 *	  POSTGRES relation descriptor (a/k/a relcache entry) definitions.
 *
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/utils/rel.h
 *
 *-------------------------------------------------------------------------
 */
#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 "nodes/bitmapset.h"
#include "rewrite/prs2lock.h"
#include "storage/block.h"
#include "storage/relfilenode.h"
#include "utils/relcache.h"
#include "utils/reltrigger.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;


/*
 * 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	amgetbitmap;
	FmgrInfo	amrescan;
	FmgrInfo	amendscan;
	FmgrInfo	ammarkpos;
	FmgrInfo	amrestrpos;
	FmgrInfo	ambuild;
	FmgrInfo	ambuildempty;
	FmgrInfo	ambulkdelete;
	FmgrInfo	amvacuumcleanup;
	FmgrInfo	amcanreturn;
	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 */
	int			rd_refcnt;		/* reference count */
	BackendId	rd_backend;		/* owning backend id, if temporary relation */
	bool		rd_islocaltemp; /* rel is a temp rel of this session */
	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 */

	/*
	 * 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 can be now be relied on, whereas previously it
	 * could be "forgotten" in earlier releases.
	 * Likewise, rd_newRelfilenodeSubid is the ID of the highest
	 * subtransaction the relfilenode change has survived into, or zero if not
	 * changed in the current transaction (or we have forgotten changing it).
	 * rd_newRelfilenodeSubid can be forgotten when a relation has multiple
	 * new relfilenodes within a single transaction, with one of them occuring
	 * in a subsequently aborted subtransaction, e.g.
	 * 		BEGIN;
	 * 		TRUNCATE t;
	 * 		SAVEPOINT save;
	 * 		TRUNCATE t;
	 * 		ROLLBACK TO save;
	 * 		-- rd_newRelfilenode is now forgotten
	 */
	SubTransactionId rd_createSubid;	/* rel was created in current xact */
	SubTransactionId rd_newRelfilenodeSubid;	/* new relfilenode assigned in
												 * current xact */

	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 */
	Bitmapset  *rd_indexattr;	/* identifies columns used in indexes */
	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 */
	/* use "struct" here to avoid needing to include htup.h: */
	struct HeapTupleData *rd_indextuple;		/* all of pg_index tuple */
	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 support procs for each opclass are cached, namely
	 * those with lefttype and righttype equal to the opclass's opcintype. The
	 * arrays are indexed by support function 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_opfamily;	/* OIDs of op families for each index col */
	Oid		   *rd_opcintype;	/* OIDs of opclass declared input data types */
	RegProcedure *rd_support;	/* OIDs of support procedures */
	FmgrInfo   *rd_supportinfo; /* lookup info for support procedures */
	int16	   *rd_indoption;	/* per-column AM-specific flags */
	List	   *rd_indexprs;	/* index expression trees, if any */
	List	   *rd_indpred;		/* index predicate tree, if any */
	Oid		   *rd_exclops;		/* OIDs of exclusion operators, if any */
	Oid		   *rd_exclprocs;	/* OIDs of exclusion ops' procs, if any */
	uint16	   *rd_exclstrats;	/* exclusion ops' strategy numbers, if any */
	void	   *rd_amcache;		/* available for use by index AM */
	Oid		   *rd_indcollation;	/* OIDs of index collations */

	/*
	 * Hack for CLUSTER, rewriting ALTER TABLE, etc: when writing a new
	 * version of a table, we need to make any toast pointers inserted into it
	 * have the existing toast table's OID, not the OID of the transient toast
	 * table.  If rd_toastoid isn't InvalidOid, it is the OID to place in
	 * toast pointers inserted into this rel.  (Note it's set on the new
	 * version of the main heap, not the toast table itself.)  This also
	 * causes toast_save_datum() to try to preserve toast value OIDs.
	 */
	Oid			rd_toastoid;	/* Real TOAST table's OID, or InvalidOid */

	/* use "struct" here to avoid needing to include pgstat.h: */
	struct PgStat_TableStatus *pgstat_info;		/* statistics collection area */
} RelationData;

/*
 * 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.
 */
 /* autovacuum-related reloptions. */
typedef struct AutoVacOpts
{
	bool		enabled;
	int			vacuum_threshold;
	int			analyze_threshold;
	int			vacuum_cost_delay;
	int			vacuum_cost_limit;
	int			freeze_min_age;
	int			freeze_max_age;
	int			freeze_table_age;
	float8		vacuum_scale_factor;
	float8		analyze_scale_factor;
} AutoVacOpts;

typedef struct StdRdOptions
{
	int32		vl_len_;		/* varlena header (do not touch directly!) */
	int			fillfactor;		/* page fill factor in percent (0..100) */
	AutoVacOpts autovacuum;		/* autovacuum-related options */
	bool		security_barrier;		/* for views */
} 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)

/*
 * RelationIsSecurityView
 *		Returns whether the relation is security view, or not
 */
#define RelationIsSecurityView(relation)	\
	((relation)->rd_options ?				\
	 ((StdRdOptions *) (relation)->rd_options)->security_barrier : false)

/*
 * 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)

/*
 * RelationIsMapped
 *		True if the relation uses the relfilenode map.
 *
 * NB: this is only meaningful for relkinds that have storage, else it
 * will misleadingly say "true".
 */
#define RelationIsMapped(relation) \
	((relation)->rd_rel->relfilenode == InvalidOid)

/*
 * 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, (relation)->rd_backend)); \
	} 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)

/*
 * RelationGetTargetBlock
 *		Fetch relation's current insertion target block.
 *
 * Returns InvalidBlockNumber if there is no current target block.	Note
 * that the target block status is discarded on any smgr-level invalidation.
 */
#define RelationGetTargetBlock(relation) \
	( (relation)->rd_smgr != NULL ? (relation)->rd_smgr->smgr_targblock : InvalidBlockNumber )

/*
 * RelationSetTargetBlock
 *		Set relation's current insertion target block.
 */
#define RelationSetTargetBlock(relation, targblock) \
	do { \
		RelationOpenSmgr(relation); \
		(relation)->rd_smgr->smgr_targblock = (targblock); \
	} while (0)

/*
 * RelationNeedsWAL
 *		True if relation needs WAL.
 */
#define RelationNeedsWAL(relation) \
	((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT)

/*
 * RelationUsesLocalBuffers
 *		True if relation's pages are stored in local buffers.
 */
#define RelationUsesLocalBuffers(relation) \
	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)

/*
 * RELATION_IS_LOCAL
 *		If a rel is either temp or newly created in the current transaction,
 *		it can be assumed to be accessible only to the current backend.
 *		This is typically used to decide that we can skip acquiring locks.
 *
 * Beware of multiple eval of argument
 */
#define RELATION_IS_LOCAL(relation) \
	((relation)->rd_islocaltemp || \
	 (relation)->rd_createSubid != InvalidSubTransactionId)

/*
 * RELATION_IS_OTHER_TEMP
 *		Test for a temporary relation that belongs to some other session.
 *
 * Beware of multiple eval of argument
 */
#define RELATION_IS_OTHER_TEMP(relation) \
	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP && \
	 !(relation)->rd_islocaltemp)

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

#endif   /* REL_H */