mirror of https://github.com/postgres/postgres
do anything yet, but it has the necessary connections to initialization and so forth. Make some gestures towards allowing number of blocks in a relation to be BlockNumber, ie, unsigned int, rather than signed int. (I doubt I got all the places that are sloppy about it, yet.) On the way, replace the hardwired NLOCKS_PER_XACT fudge factor with a GUC variable.REL7_2_STABLE
Tom Lane
25 years ago
parent
b559382134
commit
e0c9301c87
@ -0,0 +1,30 @@ |
||||
#-------------------------------------------------------------------------
|
||||
#
|
||||
# Makefile--
|
||||
# Makefile for storage/freespace
|
||||
#
|
||||
# IDENTIFICATION
|
||||
# $Header: /cvsroot/pgsql/src/backend/storage/freespace/Makefile,v 1.1 2001/06/27 23:31:39 tgl Exp $
|
||||
#
|
||||
#-------------------------------------------------------------------------
|
||||
|
||||
subdir = src/backend/storage/freespace
|
||||
top_builddir = ../../../..
|
||||
include $(top_builddir)/src/Makefile.global |
||||
|
||||
OBJS = freespace.o
|
||||
|
||||
all: SUBSYS.o |
||||
|
||||
SUBSYS.o: $(OBJS) |
||||
$(LD) $(LDREL) $(LDOUT) SUBSYS.o $(OBJS)
|
||||
|
||||
depend dep: |
||||
$(CC) -MM $(CFLAGS) *.c >depend
|
||||
|
||||
clean: |
||||
rm -f SUBSYS.o $(OBJS)
|
||||
|
||||
ifeq (depend,$(wildcard depend)) |
||||
include depend |
||||
endif |
||||
@ -0,0 +1,183 @@ |
||||
/*-------------------------------------------------------------------------
|
||||
* |
||||
* freespace.c |
||||
* POSTGRES free space map for quickly finding free space in relations |
||||
* |
||||
* |
||||
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group |
||||
* Portions Copyright (c) 1994, Regents of the University of California |
||||
* |
||||
* IDENTIFICATION |
||||
* $Header: /cvsroot/pgsql/src/backend/storage/freespace/freespace.c,v 1.1 2001/06/27 23:31:39 tgl Exp $ |
||||
* |
||||
*------------------------------------------------------------------------- |
||||
*/ |
||||
#include "postgres.h" |
||||
|
||||
#include "storage/freespace.h" |
||||
#include "storage/itemid.h" |
||||
#include "storage/shmem.h" |
||||
|
||||
|
||||
/*
|
||||
* Shared free-space-map objects |
||||
* |
||||
* Note: we handle pointers to these items as pointers, not as SHMEM_OFFSETs. |
||||
* This assumes that all processes accessing the map will have the shared |
||||
* memory segment mapped at the same place in their address space. |
||||
*/ |
||||
typedef struct FSMHeader FSMHeader; |
||||
typedef struct FSMRelation FSMRelation; |
||||
typedef struct FSMChunk FSMChunk; |
||||
|
||||
/* Header for whole map */ |
||||
struct FSMHeader |
||||
{ |
||||
HTAB *relationHash; /* hashtable of FSMRelation entries */ |
||||
FSMRelation *relationList; /* FSMRelations in order by recency of use */ |
||||
int numRelations; /* number of FSMRelations now in use */ |
||||
FSMChunk *freeChunks; /* linked list of currently-free chunks */ |
||||
}; |
||||
|
||||
/*
|
||||
* Per-relation struct --- this is an entry in the shared hash table. |
||||
* The hash key is the RelFileNode value (hence, we look at the physical |
||||
* relation ID, not the logical ID, which is appropriate). |
||||
*/ |
||||
struct FSMRelation |
||||
{ |
||||
RelFileNode key; /* hash key (must be first) */ |
||||
FSMRelation *nextRel; /* next rel in order by recency of use */ |
||||
FSMRelation *priorRel; /* prior rel in order by recency of use */ |
||||
FSMChunk *relChunks; /* linked list of page info chunks */ |
||||
}; |
||||
|
||||
#define SHMEM_FSMHASH_KEYSIZE sizeof(RelFileNode) |
||||
#define SHMEM_FSMHASH_DATASIZE (sizeof(FSMRelation) - SHMEM_FSMHASH_KEYSIZE) |
||||
|
||||
#define CHUNKPAGES 32 /* each chunk can store this many pages */ |
||||
|
||||
struct FSMChunk |
||||
{ |
||||
FSMChunk *next; /* linked-list link */ |
||||
int numPages; /* number of pages described here */ |
||||
BlockNumber pages[CHUNKPAGES]; /* page numbers within relation */ |
||||
ItemLength bytes[CHUNKPAGES]; /* free space available on each page */ |
||||
}; |
||||
|
||||
|
||||
SPINLOCK FreeSpaceLock; /* in Shmem or created in
|
||||
* CreateSpinlocks() */ |
||||
|
||||
int MaxFSMRelations; /* these are set by guc.c */ |
||||
int MaxFSMPages; |
||||
|
||||
static FSMHeader *FreeSpaceMap; /* points to FSMHeader in shared memory */ |
||||
|
||||
|
||||
/*
|
||||
* InitFreeSpaceMap -- Initialize the freespace module. |
||||
* |
||||
* This must be called once during shared memory initialization. |
||||
* It builds the empty free space map table. FreeSpaceLock must also be |
||||
* initialized at some point, but is not touched here --- we assume there is |
||||
* no need for locking, since only the calling process can be accessing shared |
||||
* memory as yet. FreeSpaceShmemSize() was called previously while computing |
||||
* the space needed for shared memory. |
||||
*/ |
||||
void |
||||
InitFreeSpaceMap(void) |
||||
{ |
||||
HASHCTL info; |
||||
FSMChunk *chunks, |
||||
*prevchunk; |
||||
int nchunks; |
||||
|
||||
/* Create table header */ |
||||
FreeSpaceMap = (FSMHeader *) ShmemAlloc(sizeof(FSMHeader)); |
||||
if (FreeSpaceMap == NULL) |
||||
elog(FATAL, "Insufficient shared memory for free space map"); |
||||
MemSet(FreeSpaceMap, 0, sizeof(FSMHeader)); |
||||
|
||||
/* Create hashtable for FSMRelations */ |
||||
info.keysize = SHMEM_FSMHASH_KEYSIZE; |
||||
info.datasize = SHMEM_FSMHASH_DATASIZE; |
||||
info.hash = tag_hash; |
||||
|
||||
FreeSpaceMap->relationHash = ShmemInitHash("Free Space Map Hash", |
||||
MaxFSMRelations / 10, |
||||
MaxFSMRelations, |
||||
&info, |
||||
(HASH_ELEM | HASH_FUNCTION)); |
||||
|
||||
if (!FreeSpaceMap->relationHash) |
||||
elog(FATAL, "Insufficient shared memory for free space map"); |
||||
|
||||
/* Allocate FSMChunks and fill up the free-chunks list */ |
||||
nchunks = (MaxFSMPages - 1) / CHUNKPAGES + 1; |
||||
|
||||
chunks = (FSMChunk *) ShmemAlloc(nchunks * sizeof(FSMChunk)); |
||||
if (chunks == NULL) |
||||
elog(FATAL, "Insufficient shared memory for free space map"); |
||||
|
||||
prevchunk = NULL; |
||||
while (nchunks-- > 0) |
||||
{ |
||||
chunks->next = prevchunk; |
||||
prevchunk = chunks; |
||||
chunks++; |
||||
} |
||||
FreeSpaceMap->freeChunks = prevchunk; |
||||
} |
||||
|
||||
|
||||
int |
||||
FreeSpaceShmemSize(void) |
||||
{ |
||||
int size; |
||||
int nchunks; |
||||
|
||||
/*
|
||||
* There is no point in allowing less than one "chunk" per relation, |
||||
* so force MaxFSMPages to be at least CHUNKPAGES * MaxFSMRelations. |
||||
*/ |
||||
Assert(MaxFSMRelations > 0); |
||||
if (MaxFSMPages < CHUNKPAGES * MaxFSMRelations) |
||||
MaxFSMPages = CHUNKPAGES * MaxFSMRelations; |
||||
|
||||
/* table header */ |
||||
size = MAXALIGN(sizeof(FSMHeader)); |
||||
|
||||
/* hash table, including the FSMRelation objects */ |
||||
size += hash_estimate_size(MaxFSMRelations, |
||||
SHMEM_FSMHASH_KEYSIZE, |
||||
SHMEM_FSMHASH_DATASIZE); |
||||
|
||||
/* FSMChunk objects */ |
||||
nchunks = (MaxFSMPages - 1) / CHUNKPAGES + 1; |
||||
|
||||
size += MAXALIGN(nchunks * sizeof(FSMChunk)); |
||||
|
||||
return size; |
||||
} |
||||
|
||||
|
||||
void |
||||
FreeSpaceMapForgetRel(RelFileNode *rel) |
||||
{ |
||||
} |
||||
|
||||
|
||||
#ifdef FREESPACE_DEBUG |
||||
/*
|
||||
* Dump contents of freespace map for debugging. |
||||
* |
||||
* We assume caller holds the FreeSpaceLock, or is otherwise unconcerned |
||||
* about other processes. |
||||
*/ |
||||
void |
||||
DumpFreeSpace(void) |
||||
{ |
||||
} |
||||
|
||||
#endif /* FREESPACE_DEBUG */ |
||||
@ -0,0 +1,53 @@ |
||||
/*-------------------------------------------------------------------------
|
||||
* |
||||
* freespace.h |
||||
* POSTGRES free space map for quickly finding free space in relations |
||||
* |
||||
* |
||||
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group |
||||
* Portions Copyright (c) 1994, Regents of the University of California |
||||
* |
||||
* $Id: freespace.h,v 1.1 2001/06/27 23:31:39 tgl Exp $ |
||||
* |
||||
*------------------------------------------------------------------------- |
||||
*/ |
||||
#ifndef FREESPACE_H_ |
||||
#define FREESPACE_H_ |
||||
|
||||
#include "storage/block.h" |
||||
#include "storage/relfilenode.h" |
||||
#include "storage/spin.h" |
||||
|
||||
|
||||
extern SPINLOCK FreeSpaceLock; |
||||
|
||||
extern int MaxFSMRelations; |
||||
extern int MaxFSMPages; |
||||
|
||||
|
||||
/*
|
||||
* function prototypes |
||||
*/ |
||||
extern void InitFreeSpaceMap(void); |
||||
extern int FreeSpaceShmemSize(void); |
||||
|
||||
extern BlockNumber GetPageWithFreeSpace(RelFileNode *rel, Size spaceNeeded); |
||||
extern void RecordFreeSpace(RelFileNode *rel, BlockNumber page, |
||||
Size spaceAvail); |
||||
extern BlockNumber RecordAndGetPageWithFreeSpace(RelFileNode *rel, |
||||
BlockNumber oldPage, |
||||
Size oldSpaceAvail, |
||||
Size spaceNeeded); |
||||
extern void MultiRecordFreeSpace(RelFileNode *rel, |
||||
BlockNumber minPage, |
||||
BlockNumber maxPage, |
||||
int nPages, |
||||
BlockNumber *pages, |
||||
Size *spaceAvail); |
||||
extern void FreeSpaceMapForgetRel(RelFileNode *rel); |
||||
|
||||
#ifdef FREESPACE_DEBUG |
||||
extern void DumpFreeSpace(void); |
||||
#endif |
||||
|
||||
#endif /* FREESPACE_H */ |
||||
Loading…
Reference in new issue