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Reduce default file size limit to 1Gb, and move the 

configuration constant to config.h.
This commit is contained in:
Tom Lane 1999-04-05 22:25:11 +00:00
parent 9cae93d309
commit 5ce851dcda
2 changed files with 23 additions and 29 deletions
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35
src/backend/storage/smgr/md.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.41 1999/02/13 23:18:35 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.42 1999/04/05 22:25:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -33,10 +33,11 @@
* The magnetic disk storage manager keeps track of open file descriptors
* in its own descriptor pool. This happens for two reasons. First, at
* transaction boundaries, we walk the list of descriptors and flush
* anything that we've dirtied in the current transaction. Second, we
* have to support relations of > 4GBytes. In order to do this, we break
* relations up into chunks of < 2GBytes and store one chunk in each of
* several files that represent the relation.
* anything that we've dirtied in the current transaction. Second, we want
* to support relations larger than the OS' file size limit (often 2GBytes).
* In order to do that, we break relations up into chunks of < 2GBytes
* and store one chunk in each of several files that represent the relation.
* See the BLCKSZ and RELSEG_SIZE configuration constants in include/config.h.
*/
typedef struct _MdfdVec
@ -59,30 +60,6 @@ static MemoryContext MdCxt;
#define MDFD_DIRTY (uint16) 0x01
#define MDFD_FREE (uint16) 0x02
/*
* RELSEG_SIZE appears to be the number of segments that can
* be in a disk file. It was defined as 262144 based on 8k
* blocks, but now that the block size can be changed, this
* has to be calculated at compile time. Otherwise, the file
* size limit would not work out to 2-gig (2147483648).
*
* The number needs to be (2 ** 31) / BLCKSZ, but to be keep
* the math under MAXINT, pre-divide by 256 and use ...
*
* (((2 ** 23) / BLCKSZ) * (2 ** 8))
*
* 07 Jan 98 darrenk
*
* Now possibly let the OS handle it...
*
* 19 Mar 98 darrenk
*
*/
#ifndef LET_OS_MANAGE_FILESIZE
#define RELSEG_SIZE ((8388608 / BLCKSZ) * 256)
#endif
/* routines declared here */
static MdfdVec *_mdfd_openseg(Relation reln, int segno, int oflags);
static MdfdVec *_mdfd_getseg(Relation reln, int blkno, int oflag);

17
src/include/config.h.in
View File

@ -27,6 +27,23 @@
*/
#define BLCKSZ 8192
/*
* RELSEG_SIZE is the maximum number of blocks allowed in one disk file.
* Thus, the maximum size of a single file is RELSEG_SIZE * BLCKSZ;
* relations bigger than that are divided into multiple files.
*
* CAUTION: RELSEG_SIZE * BLCKSZ must be less than your OS' limit on file size.
* This is typically 2Gb or 4Gb in a 32-bit operating system. By default,
* we make the limit one billion bytes to avoid any possible integer-overflow
* problems within the OS. A limit smaller than necessary only means we
* divide a large relation into more chunks than necessary, so it seems best
* to err in the direction of a small limit.
*
* CAUTION: you had best do an initdb if you change either BLCKSZ or
* RELSEG_SIZE.
*/
#define RELSEG_SIZE (1000000000 / BLCKSZ)
/*
* The following is set using configure.
*/