diff options
Diffstat (limited to 'src/include/storage/sinvaladt.h')
| -rw-r--r-- | src/include/storage/sinvaladt.h | 91 |
1 files changed, 8 insertions, 83 deletions
diff --git a/src/include/storage/sinvaladt.h b/src/include/storage/sinvaladt.h index d480556dc99..012ce2d92ca 100644 --- a/src/include/storage/sinvaladt.h +++ b/src/include/storage/sinvaladt.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.45 2008/01/01 19:45:59 momjian Exp $ + * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.46 2008/03/16 19:47:34 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -16,55 +16,16 @@ #include "storage/sinval.h" - /* * The shared cache invalidation manager is responsible for transmitting * invalidation messages between backends. Any message sent by any backend * must be delivered to all already-running backends before it can be * forgotten. - * - * Conceptually, the messages are stored in an infinite array, where - * maxMsgNum is the next array subscript to store a submitted message in, - * minMsgNum is the smallest array subscript containing a message not yet - * read by all backends, and we always have maxMsgNum >= minMsgNum. (They - * are equal when there are no messages pending.) For each active backend, - * there is a nextMsgNum pointer indicating the next message it needs to read; - * we have maxMsgNum >= nextMsgNum >= minMsgNum for every backend. - * - * In reality, the messages are stored in a circular buffer of MAXNUMMESSAGES - * entries. We translate MsgNum values into circular-buffer indexes by - * computing MsgNum % MAXNUMMESSAGES (this should be fast as long as - * MAXNUMMESSAGES is a constant and a power of 2). As long as maxMsgNum - * doesn't exceed minMsgNum by more than MAXNUMMESSAGES, we have enough space - * in the buffer. If the buffer does overflow, we reset it to empty and - * force each backend to "reset", ie, discard all its invalidatable state. - * - * We would have problems if the MsgNum values overflow an integer, so - * whenever minMsgNum exceeds MSGNUMWRAPAROUND, we subtract MSGNUMWRAPAROUND - * from all the MsgNum variables simultaneously. MSGNUMWRAPAROUND can be - * large so that we don't need to do this often. It must be a multiple of - * MAXNUMMESSAGES so that the existing circular-buffer entries don't need - * to be moved when we do it. - * + * * The struct type SharedInvalidationMessage, defining the contents of * a single message, is defined in sinval.h. */ - -/* - * Configurable parameters. - * - * MAXNUMMESSAGES: max number of shared-inval messages we can buffer. - * Must be a power of 2 for speed. - * - * MSGNUMWRAPAROUND: how often to reduce MsgNum variables to avoid overflow. - * Must be a multiple of MAXNUMMESSAGES. Should be large. - */ - -#define MAXNUMMESSAGES 4096 -#define MSGNUMWRAPAROUND (MAXNUMMESSAGES * 4096) - - /* Per-backend state in shared invalidation structure */ typedef struct ProcState { @@ -73,53 +34,17 @@ typedef struct ProcState bool resetState; /* true, if backend has to reset its state */ } ProcState; -/* Shared cache invalidation memory segment */ -typedef struct SISeg -{ - /* - * General state information - */ - int minMsgNum; /* oldest message still needed */ - int maxMsgNum; /* next message number to be assigned */ - int lastBackend; /* index of last active procState entry, +1 */ - int maxBackends; /* size of procState array */ - int freeBackends; /* number of empty procState slots */ - - /* - * Next LocalTransactionId to use for each idle backend slot. We keep - * this here because it is indexed by BackendId and it is convenient to - * copy the value to and from local memory when MyBackendId is set. - */ - LocalTransactionId *nextLXID; /* array of maxBackends entries */ - - /* - * Circular buffer holding shared-inval messages - */ - SharedInvalidationMessage buffer[MAXNUMMESSAGES]; - - /* - * Per-backend state info. - * - * We declare procState as 1 entry because C wants a fixed-size array, but - * actually it is maxBackends entries long. - */ - ProcState procState[1]; /* reflects the invalidation state */ -} SISeg; - - -extern SISeg *shmInvalBuffer; /* pointer to the shared inval buffer */ - /* * prototypes for functions in sinvaladt.c */ -extern void SIBufferInit(void); -extern int SIBackendInit(SISeg *segP); +extern Size SInvalShmemSize(void); +extern void CreateSharedInvalidationState(void); +extern void SharedInvalBackendInit(void); -extern bool SIInsertDataEntry(SISeg *segP, SharedInvalidationMessage *data); -extern int SIGetDataEntry(SISeg *segP, int backendId, - SharedInvalidationMessage *data); -extern void SIDelExpiredDataEntries(SISeg *segP); +extern bool SIInsertDataEntry(SharedInvalidationMessage *data); +extern int SIGetDataEntry(int backendId, SharedInvalidationMessage *data); +extern void SIDelExpiredDataEntries(bool locked); extern LocalTransactionId GetNextLocalTransactionId(void); |