@ -7,7 +7,7 @@
* Portions Copyright ( c ) 1996 - 2001 , PostgreSQL Global Development Group
* Portions Copyright ( c ) 1994 , Regents of the University of California
*
* $ Id : sinval . h , v 1.18 2001 / 02 / 26 00 : 50 : 08 tgl Exp $
* $ Id : sinval . h , v 1.19 2001 / 06 / 19 19 : 42 : 16 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -17,15 +17,61 @@
# include "storage/itemptr.h"
# include "storage/spin.h"
/*
* We currently support two types of shared - invalidation messages : one that
* invalidates an entry in a catcache , and one that invalidates a relcache
* entry . More types could be added if needed . The message type is
* identified by the first " int16 " field of the message struct . Zero or
* positive means a catcache inval message ( and also serves as the catcache
* ID field ) . - 1 means a relcache inval message . Other negative values
* are available to identify other inval message types .
*
* Shared - inval events are initially driven by detecting tuple inserts ,
* updates and deletions in system catalogs ( see RelationInvalidateHeapTuple
* and RelationMark4RollbackHeapTuple ) . Note that some system catalogs have
* multiple caches on them ( with different indexes ) . On detecting a tuple
* invalidation in such a catalog , a separate catcache inval message must be
* generated for each of its caches . The catcache inval message carries the
* hash index for the target tuple , so that the catcache only needs to search
* one hash chain not all its chains . Of course this assumes that all the
* backends are using identical hashing code , but that should be OK .
*/
typedef struct
{
int16 id ; /* cache ID --- must be first */
uint16 hashIndex ; /* hashchain index within this catcache */
Oid dbId ; /* database ID, or 0 if a shared relation */
ItemPointerData tuplePtr ; /* tuple identifier in cached relation */
} SharedInvalCatcacheMsg ;
# define SHAREDINVALRELCACHE_ID (-1)
typedef struct
{
int16 id ; /* type field --- must be first */
Oid dbId ; /* database ID, or 0 if a shared relation */
Oid relId ; /* relation ID */
} SharedInvalRelcacheMsg ;
typedef union
{
int16 id ; /* type field --- must be first */
SharedInvalCatcacheMsg cc ;
SharedInvalRelcacheMsg rc ;
} SharedInvalidationMessage ;
extern SPINLOCK SInvalLock ;
extern int SInvalShmemSize ( int maxBackends ) ;
extern void CreateSharedInvalidationState ( int maxBackends ) ;
extern void InitBackendSharedInvalidationState ( void ) ;
extern void RegisterSharedInvalid ( int cacheId , Index hashIndex ,
ItemPointer pointer ) ;
extern void InvalidateSharedInvalid ( void ( * invalFunction ) ( ) ,
void ( * resetFunction ) ( ) ) ;
extern void SendSharedInvalidMessage ( SharedInvalidationMessage * msg ) ;
extern void ReceiveSharedInvalidMessages (
void ( * invalFunction ) ( SharedInvalidationMessage * msg ) ,
void ( * resetFunction ) ( void ) ) ;
extern bool DatabaseHasActiveBackends ( Oid databaseId , bool ignoreMyself ) ;
extern bool TransactionIdIsInProgress ( TransactionId xid ) ;
Tom Lane
25 years ago