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Provide a build-time option to store large relations as single files, rather

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than dividing them into 1GB segments as has been our longtime practice.  This
requires working support for large files in the operating system; at least for
the time being, it won't be the default.

Zdenek Kotala
This commit is contained in:
Tom Lane
2008-03-10 20:06:27 +00:00
parent b6912af22b
commit f0828b2fc3
12 changed files with 595 additions and 100 deletions
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41
src/backend/storage/file/buffile.c
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.29 2008/01/01 19:45:51 momjian Exp $
* $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.30 2008/03/10 20:06:27 tgl Exp $
*
* NOTES:
*
@@ -38,13 +38,12 @@
#include "storage/buffile.h"
/*
* The maximum safe file size is presumed to be RELSEG_SIZE * BLCKSZ.
* Note we adhere to this limit whether or not LET_OS_MANAGE_FILESIZE
* is defined, although md.c ignores it when that symbol is defined.
* The reason for doing this is that we'd like large temporary BufFiles
* to be spread across multiple tablespaces when available.
* We break BufFiles into gigabyte-sized segments, whether or not
* USE_SEGMENTED_FILES is defined. The reason is that we'd like large
* temporary BufFiles to be spread across multiple tablespaces when available.
*/
#define MAX_PHYSICAL_FILESIZE (RELSEG_SIZE * BLCKSZ)
#define MAX_PHYSICAL_FILESIZE 0x40000000
#define BUFFILE_SEG_SIZE (MAX_PHYSICAL_FILESIZE / BLCKSZ)
/*
* This data structure represents a buffered file that consists of one or
@@ -56,7 +55,7 @@ struct BufFile
int numFiles; /* number of physical files in set */
/* all files except the last have length exactly MAX_PHYSICAL_FILESIZE */
File *files; /* palloc'd array with numFiles entries */
long *offsets; /* palloc'd array with numFiles entries */
off_t *offsets; /* palloc'd array with numFiles entries */
/*
* offsets[i] is the current seek position of files[i]. We use this to
@@ -72,7 +71,7 @@ struct BufFile
* Position as seen by user of BufFile is (curFile, curOffset + pos).
*/
int curFile; /* file index (0..n) part of current pos */
int curOffset; /* offset part of current pos */
off_t curOffset; /* offset part of current pos */
int pos; /* next read/write position in buffer */
int nbytes; /* total # of valid bytes in buffer */
char buffer[BLCKSZ];
@@ -97,7 +96,7 @@ makeBufFile(File firstfile)
file->numFiles = 1;
file->files = (File *) palloc(sizeof(File));
file->files[0] = firstfile;
file->offsets = (long *) palloc(sizeof(long));
file->offsets = (off_t *) palloc(sizeof(off_t));
file->offsets[0] = 0L;
file->isTemp = false;
file->isInterXact = false;
@@ -124,8 +123,8 @@ extendBufFile(BufFile *file)
file->files = (File *) repalloc(file->files,
(file->numFiles + 1) * sizeof(File));
file->offsets = (long *) repalloc(file->offsets,
(file->numFiles + 1) * sizeof(long));
file->offsets = (off_t *) repalloc(file->offsets,
(file->numFiles + 1) * sizeof(off_t));
file->files[file->numFiles] = pfile;
file->offsets[file->numFiles] = 0L;
file->numFiles++;
@@ -279,9 +278,9 @@ BufFileDumpBuffer(BufFile *file)
bytestowrite = file->nbytes - wpos;
if (file->isTemp)
{
long availbytes = MAX_PHYSICAL_FILESIZE - file->curOffset;
off_t availbytes = MAX_PHYSICAL_FILESIZE - file->curOffset;
if ((long) bytestowrite > availbytes)
if ((off_t) bytestowrite > availbytes)
bytestowrite = (int) availbytes;
}
@@ -451,10 +450,10 @@ BufFileFlush(BufFile *file)
* impossible seek is attempted.
*/
int
BufFileSeek(BufFile *file, int fileno, long offset, int whence)
BufFileSeek(BufFile *file, int fileno, off_t offset, int whence)
{
int newFile;
long newOffset;
off_t newOffset;
switch (whence)
{
@@ -469,7 +468,7 @@ BufFileSeek(BufFile *file, int fileno, long offset, int whence)
/*
* Relative seek considers only the signed offset, ignoring
* fileno. Note that large offsets (> 1 gig) risk overflow in this
* add...
* add, unless we have 64-bit off_t.
*/
newFile = file->curFile;
newOffset = (file->curOffset + file->pos) + offset;
@@ -537,7 +536,7 @@ BufFileSeek(BufFile *file, int fileno, long offset, int whence)
}
void
BufFileTell(BufFile *file, int *fileno, long *offset)
BufFileTell(BufFile *file, int *fileno, off_t *offset)
{
*fileno = file->curFile;
*offset = file->curOffset + file->pos;
@@ -558,8 +557,8 @@ int
BufFileSeekBlock(BufFile *file, long blknum)
{
return BufFileSeek(file,
(int) (blknum / RELSEG_SIZE),
(blknum % RELSEG_SIZE) * BLCKSZ,
(int) (blknum / BUFFILE_SEG_SIZE),
(off_t) (blknum % BUFFILE_SEG_SIZE) * BLCKSZ,
SEEK_SET);
}
@@ -575,7 +574,7 @@ BufFileTellBlock(BufFile *file)
long blknum;
blknum = (file->curOffset + file->pos) / BLCKSZ;
blknum += file->curFile * RELSEG_SIZE;
blknum += file->curFile * BUFFILE_SEG_SIZE;
return blknum;
}