diff options
Diffstat (limited to 'src/include/storage/buf_internals.h')
| -rw-r--r-- | src/include/storage/buf_internals.h | 67 |
1 files changed, 29 insertions, 38 deletions
diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index b795d65fb20..ca1e1dd4b49 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -7,17 +7,19 @@ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: buf_internals.h,v 1.48 2001/03/22 04:01:05 momjian Exp $ + * $Id: buf_internals.h,v 1.49 2001/07/06 21:04:26 tgl Exp $ * *------------------------------------------------------------------------- */ #ifndef BUFMGR_INTERNALS_H #define BUFMGR_INTERNALS_H +#include "storage/backendid.h" #include "storage/buf.h" #include "storage/lmgr.h" #include "storage/s_lock.h" + /* Buf Mgr constants */ /* in bufmgr.c */ extern int Data_Descriptors; @@ -38,9 +40,19 @@ extern int ShowPinTrace; #define BM_IO_IN_PROGRESS (1 << 5) #define BM_IO_ERROR (1 << 6) #define BM_JUST_DIRTIED (1 << 7) +#define BM_PIN_COUNT_WAITER (1 << 8) typedef bits16 BufFlags; +/* + * Buffer tag identifies which disk block the buffer contains. + * + * Note: the BufferTag data must be sufficient to determine where to write the + * block, even during a "blind write" with no relcache entry. It's possible + * that the backend flushing the buffer doesn't even believe the relation is + * visible yet (its xact may have started before the xact that created the + * rel). The storage manager must be able to cope anyway. + */ typedef struct buftag { RelFileNode rnode; @@ -61,27 +73,8 @@ typedef struct buftag ) /* - * We don't need this data any more but it allows more user - * friendly error messages. Feel free to get rid of it - * (and change a lot of places -:)) - */ -typedef struct bufblindid -{ - char dbname[NAMEDATALEN]; /* name of db in which buf belongs */ - char relname[NAMEDATALEN]; /* name of reln */ -} BufferBlindId; - -/* * BufferDesc -- shared buffer cache metadata for a single * shared buffer descriptor. - * - * We keep the name of the database and relation in which this - * buffer appears in order to avoid a catalog lookup on cache - * flush if we don't have the reldesc in the cache. It is also - * possible that the relation to which this buffer belongs is - * not visible to all backends at the time that it gets flushed. - * Dbname, relname, dbid, and relid are enough to determine where - * to put the buffer, for all storage managers. */ typedef struct sbufdesc { @@ -89,14 +82,14 @@ typedef struct sbufdesc Buffer freePrev; SHMEM_OFFSET data; /* pointer to data in buf pool */ - /* tag and id must be together for table lookup to work */ + /* tag and id must be together for table lookup (still true?) */ BufferTag tag; /* file/block identifier */ - int buf_id; /* maps global desc to local desc */ + int buf_id; /* buffer's index number (from 0) */ BufFlags flags; /* see bit definitions above */ - unsigned refcount; /* # of times buffer is pinned */ + unsigned refcount; /* # of backends holding pins on buffer */ - slock_t io_in_progress_lock; /* to block for I/O to complete */ + slock_t io_in_progress_lock; /* to wait for I/O to complete */ slock_t cntx_lock; /* to lock access to page context */ unsigned r_locks; /* # of shared locks */ @@ -105,15 +98,14 @@ typedef struct sbufdesc bool cntxDirty; /* new way to mark block as dirty */ - BufferBlindId blind; /* was used to support blind write */ - /* - * When we can't delete item from page (someone else has buffer - * pinned) we mark buffer for cleanup by specifying appropriate for - * buffer content cleanup function. Buffer will be cleaned up from - * release buffer functions. + * We can't physically remove items from a disk page if another backend + * has the buffer pinned. Hence, a backend may need to wait for all + * other pins to go away. This is signaled by setting its own backend ID + * into wait_backend_id and setting flag bit BM_PIN_COUNT_WAITER. + * At present, there can be only one such waiter per buffer. */ - void (*CleanupFunc) (Buffer); + BackendId wait_backend_id; /* backend ID of pin-count waiter */ } BufferDesc; #define BufferDescriptorGetBuffer(bdesc) ((bdesc)->buf_id + 1) @@ -128,21 +120,23 @@ typedef struct sbufdesc #define BL_R_LOCK (1 << 1) #define BL_RI_LOCK (1 << 2) #define BL_W_LOCK (1 << 3) +#define BL_PIN_COUNT_LOCK (1 << 4) /* * mao tracing buffer allocation */ /*#define BMTRACE*/ + #ifdef BMTRACE typedef struct _bmtrace { int bmt_pid; - long bmt_buf; - long bmt_dbid; - long bmt_relid; - int bmt_blkno; + int bmt_buf; + Oid bmt_dbid; + Oid bmt_relid; + BlockNumber bmt_blkno; int bmt_op; #define BMT_NOTUSED 0 @@ -162,9 +156,7 @@ typedef struct _bmtrace /* Internal routines: only called by buf.c */ /*freelist.c*/ -extern void AddBufferToFreelist(BufferDesc *bf); extern void PinBuffer(BufferDesc *buf); -extern void PinBuffer_Debug(char *file, int line, BufferDesc *buf); extern void UnpinBuffer(BufferDesc *buf); extern BufferDesc *GetFreeBuffer(void); extern void InitFreeList(bool init); @@ -179,7 +171,6 @@ extern bool BufTableInsert(BufferDesc *buf); extern BufferDesc *BufferDescriptors; extern bits8 *BufferLocks; extern BufferTag *BufferTagLastDirtied; -extern BufferBlindId *BufferBlindLastDirtied; extern LockRelId *BufferRelidLastDirtied; extern bool *BufferDirtiedByMe; extern SPINLOCK BufMgrLock; |