src/include/utils/resowner.h

/*-------------------------------------------------------------------------
 *
 * resowner.h
 *	  POSTGRES resource owner definitions.
 *
 * Query-lifespan resources are tracked by associating them with
 * ResourceOwner objects.  This provides a simple mechanism for ensuring
 * that such resources are freed at the right time.
 * See utils/resowner/README for more info.
 *
 *
 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/utils/resowner.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef RESOWNER_H
#define RESOWNER_H

#include "storage/fd.h"
#include "utils/catcache.h"
#include "utils/plancache.h"
#include "utils/snapshot.h"

/*
 * ResourceOwner objects are an opaque data structure known only within
 * resowner.c.
 */
typedef struct ResourceOwnerData *ResourceOwner;
typedef struct CachedPlan CachedPlan;


/*
 * Globally known ResourceOwners
 */
extern PGDLLIMPORT ResourceOwner CurrentResourceOwner;
extern PGDLLIMPORT ResourceOwner CurTransactionResourceOwner;
extern PGDLLIMPORT ResourceOwner TopTransactionResourceOwner;
extern PGDLLIMPORT ResourceOwner AuxProcessResourceOwner;

/*
 * Resource releasing is done in three phases: pre-locks, locks, and
 * post-locks.  The pre-lock phase must release any resources that are
 * visible to other backends (such as pinned buffers); this ensures that
 * when we release a lock that another backend may be waiting on, it will
 * see us as being fully out of our transaction.  The post-lock phase
 * should be used for backend-internal cleanup.
 */
typedef enum
{
	RESOURCE_RELEASE_BEFORE_LOCKS,
	RESOURCE_RELEASE_LOCKS,
	RESOURCE_RELEASE_AFTER_LOCKS
} ResourceReleasePhase;

/*
 *	Dynamically loaded modules can get control during ResourceOwnerRelease
 *	by providing a callback of this form.
 */
typedef void (*ResourceReleaseCallback) (ResourceReleasePhase phase,
										 bool isCommit,
										 bool isTopLevel,
										 void *arg);

typedef void (*ResourceWalkerCallback) (const struct ResourceOwnerData * owner);

/*
 * Functions in resowner.c
 */

/* generic routines */
extern ResourceOwner ResourceOwnerCreate(ResourceOwner parent,
										 const char *name);
extern void ResourceOwnerRelease(ResourceOwner owner,
								 ResourceReleasePhase phase,
								 bool isCommit,
								 bool isTopLevel);
extern void ResourceOwnerReleaseAllPlanCacheRefs(ResourceOwner owner);
extern void ResourceOwnerDelete(ResourceOwner owner);
extern ResourceOwner ResourceOwnerGetParent(ResourceOwner owner);
extern void ResourceOwnerNewParent(ResourceOwner owner,
								   ResourceOwner newparent);
extern void RegisterResourceReleaseCallback(ResourceReleaseCallback callback,
											void *arg);
extern void UnregisterResourceReleaseCallback(ResourceReleaseCallback callback,
											  void *arg);
extern void CreateAuxProcessResourceOwner(void);
extern void ReleaseAuxProcessResources(bool isCommit);

/* support for buffer refcount management */
extern void ResourceOwnerEnlargeBuffers(ResourceOwner owner);
extern void ResourceOwnerRememberBuffer(ResourceOwner owner, Buffer buffer);
extern void ResourceOwnerForgetBuffer(ResourceOwner owner, Buffer buffer);

/* support for local lock management */
struct LOCALLOCK;
extern void ResourceOwnerRememberLock(ResourceOwner owner, struct LOCALLOCK *locallock);
extern void ResourceOwnerForgetLock(ResourceOwner owner, struct LOCALLOCK *locallock);

/* support for catcache refcount management */
extern void ResourceOwnerEnlargeCatCacheRefs(ResourceOwner owner);
extern void ResourceOwnerRememberCatCacheRef(ResourceOwner owner,
								 HeapTuple tuple);
extern void ResourceOwnerForgetCatCacheRef(ResourceOwner owner,
							   HeapTuple tuple);
extern void ResourceOwnerEnlargeCatCacheListRefs(ResourceOwner owner);
extern void ResourceOwnerRememberCatCacheListRef(ResourceOwner owner,
									 CatCList *list);
extern void ResourceOwnerForgetCatCacheListRef(ResourceOwner owner,
								   CatCList *list);

/* support for relcache refcount management */
extern void ResourceOwnerEnlargeRelationRefs(ResourceOwner owner);
extern void ResourceOwnerRememberRelationRef(ResourceOwner owner,
								 Relation rel);
extern void ResourceOwnerForgetRelationRef(ResourceOwner owner,
							   Relation rel);

/* support for plancache refcount management */
extern void ResourceOwnerEnlargePlanCacheRefs(ResourceOwner owner);
extern void ResourceOwnerRememberPlanCacheRef(ResourceOwner owner,
								  CachedPlan *plan);
extern void ResourceOwnerForgetPlanCacheRef(ResourceOwner owner,
								CachedPlan *plan);

/* support for tupledesc refcount management */
extern void ResourceOwnerEnlargeTupleDescs(ResourceOwner owner);
extern void ResourceOwnerRememberTupleDesc(ResourceOwner owner,
							   TupleDesc tupdesc);
extern void ResourceOwnerForgetTupleDesc(ResourceOwner owner,
							 TupleDesc tupdesc);

/* support for snapshot refcount management */
extern void ResourceOwnerEnlargeSnapshots(ResourceOwner owner);
extern void ResourceOwnerRememberSnapshot(ResourceOwner owner,
							  Snapshot snapshot);
extern void ResourceOwnerForgetSnapshot(ResourceOwner owner,
							Snapshot snapshot);

/* support for temporary file management */
extern void ResourceOwnerEnlargeFiles(ResourceOwner owner);
extern void ResourceOwnerRememberFile(ResourceOwner owner,
						  File file);
extern void ResourceOwnerForgetFile(ResourceOwner owner,
						File file);

extern void CdbResourceOwnerWalker(ResourceOwner owner,
							ResourceWalkerCallback callback);

#endif							/* RESOWNER_H */