diff options
Diffstat (limited to 'src/backend/storage/buffer/buf_table.c')
| -rw-r--r-- | src/backend/storage/buffer/buf_table.c | 217 |
1 files changed, 113 insertions, 104 deletions
diff --git a/src/backend/storage/buffer/buf_table.c b/src/backend/storage/buffer/buf_table.c index 61e365ce55e..41b2b4d8ee0 100644 --- a/src/backend/storage/buffer/buf_table.c +++ b/src/backend/storage/buffer/buf_table.c @@ -1,13 +1,13 @@ /*------------------------------------------------------------------------- * * buf_table.c-- - * routines for finding buffers in the buffer pool. + * routines for finding buffers in the buffer pool. * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_table.c,v 1.4 1997/08/19 21:32:34 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_table.c,v 1.5 1997/09/07 04:48:17 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -16,30 +16,31 @@ * * Data Structures: * - * Buffers are identified by their BufferTag (buf.h). This + * Buffers are identified by their BufferTag (buf.h). This * file contains routines for allocating a shmem hash table to * map buffer tags to buffer descriptors. * * Synchronization: - * - * All routines in this file assume buffer manager spinlock is - * held by their caller. + * + * All routines in this file assume buffer manager spinlock is + * held by their caller. */ #include "postgres.h" #include "storage/bufmgr.h" -#include "storage/buf_internals.h" /* where the declarations go */ +#include "storage/buf_internals.h" /* where the declarations go */ #include "storage/shmem.h" #include "storage/spin.h" #include "utils/hsearch.h" -static HTAB *SharedBufHash; +static HTAB *SharedBufHash; -typedef struct lookup { - BufferTag key; - Buffer id; -} LookupEnt; +typedef struct lookup +{ + BufferTag key; + Buffer id; +} LookupEnt; /* * Initialize shmem hash table for mapping buffers @@ -47,109 +48,116 @@ typedef struct lookup { void InitBufTable() { - HASHCTL info; - int hash_flags; - - /* assume lock is held */ - - /* BufferTag maps to Buffer */ - info.keysize = sizeof(BufferTag); - info.datasize = sizeof(Buffer); - info.hash = tag_hash; - - hash_flags = (HASH_ELEM | HASH_FUNCTION); - - - SharedBufHash = (HTAB *) ShmemInitHash("Shared Buf Lookup Table", - NBuffers,NBuffers, - &info,hash_flags); - - if (! SharedBufHash) { - elog(FATAL,"couldn't initialize shared buffer pool Hash Tbl"); - exit(1); - } - + HASHCTL info; + int hash_flags; + + /* assume lock is held */ + + /* BufferTag maps to Buffer */ + info.keysize = sizeof(BufferTag); + info.datasize = sizeof(Buffer); + info.hash = tag_hash; + + hash_flags = (HASH_ELEM | HASH_FUNCTION); + + + SharedBufHash = (HTAB *) ShmemInitHash("Shared Buf Lookup Table", + NBuffers, NBuffers, + &info, hash_flags); + + if (!SharedBufHash) + { + elog(FATAL, "couldn't initialize shared buffer pool Hash Tbl"); + exit(1); + } + } -BufferDesc * -BufTableLookup(BufferTag *tagPtr) +BufferDesc * +BufTableLookup(BufferTag * tagPtr) { - LookupEnt * result; - bool found; - - if (tagPtr->blockNum == P_NEW) - return(NULL); - - result = (LookupEnt *) - hash_search(SharedBufHash,(char *) tagPtr,HASH_FIND,&found); - - if (! result){ - elog(WARN,"BufTableLookup: BufferLookup table corrupted"); - return(NULL); - } - if (! found) { - return(NULL); - } - return(&(BufferDescriptors[result->id])); + LookupEnt *result; + bool found; + + if (tagPtr->blockNum == P_NEW) + return (NULL); + + result = (LookupEnt *) + hash_search(SharedBufHash, (char *) tagPtr, HASH_FIND, &found); + + if (!result) + { + elog(WARN, "BufTableLookup: BufferLookup table corrupted"); + return (NULL); + } + if (!found) + { + return (NULL); + } + return (&(BufferDescriptors[result->id])); } /* * BufTableDelete */ bool -BufTableDelete(BufferDesc *buf) +BufTableDelete(BufferDesc * buf) { - LookupEnt * result; - bool found; - - /* buffer not initialized or has been removed from - * table already. BM_DELETED keeps us from removing - * buffer twice. - */ - if (buf->flags & BM_DELETED) { - return(TRUE); - } - - buf->flags |= BM_DELETED; - - result = (LookupEnt *) - hash_search(SharedBufHash,(char *) &(buf->tag),HASH_REMOVE,&found); - - if (! (result && found)) { - elog(WARN,"BufTableDelete: BufferLookup table corrupted"); - return(FALSE); - } - - return(TRUE); + LookupEnt *result; + bool found; + + /* + * buffer not initialized or has been removed from table already. + * BM_DELETED keeps us from removing buffer twice. + */ + if (buf->flags & BM_DELETED) + { + return (TRUE); + } + + buf->flags |= BM_DELETED; + + result = (LookupEnt *) + hash_search(SharedBufHash, (char *) &(buf->tag), HASH_REMOVE, &found); + + if (!(result && found)) + { + elog(WARN, "BufTableDelete: BufferLookup table corrupted"); + return (FALSE); + } + + return (TRUE); } bool -BufTableInsert(BufferDesc *buf) +BufTableInsert(BufferDesc * buf) { - LookupEnt * result; - bool found; - - /* cannot insert it twice */ - Assert (buf->flags & BM_DELETED); - buf->flags &= ~(BM_DELETED); - - result = (LookupEnt *) - hash_search(SharedBufHash,(char *) &(buf->tag),HASH_ENTER,&found); - - if (! result) { - Assert(0); - elog(WARN,"BufTableInsert: BufferLookup table corrupted"); - return(FALSE); - } - /* found something else in the table ! */ - if (found) { - Assert(0); - elog(WARN,"BufTableInsert: BufferLookup table corrupted"); - return(FALSE); - } - - result->id = buf->buf_id; - return(TRUE); + LookupEnt *result; + bool found; + + /* cannot insert it twice */ + Assert(buf->flags & BM_DELETED); + buf->flags &= ~(BM_DELETED); + + result = (LookupEnt *) + hash_search(SharedBufHash, (char *) &(buf->tag), HASH_ENTER, &found); + + if (!result) + { + Assert(0); + elog(WARN, "BufTableInsert: BufferLookup table corrupted"); + return (FALSE); + } + /* found something else in the table ! */ + if (found) + { + Assert(0); + elog(WARN, "BufTableInsert: BufferLookup table corrupted"); + return (FALSE); + } + + result->id = buf->buf_id; + return (TRUE); } /* prints out collision stats for the buf table */ @@ -157,8 +165,9 @@ BufTableInsert(BufferDesc *buf) void DBG_LookupListCheck(int nlookup) { - nlookup = 10; - - hash_stats("Shared",SharedBufHash); + nlookup = 10; + + hash_stats("Shared", SharedBufHash); } + #endif |