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Improve the treatment of partial(incomplete) blocks of relation files. 

This may solve a TODO item
* Recover or force failure when disk space is exhausted
This commit is contained in:
Hiroshi Inoue 1999-10-06 06:38:04 +00:00
parent 66fbea5041
commit 9df8ced9d1
1 changed files with 22 additions and 5 deletions
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27
src/backend/storage/smgr/md.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.55 1999/09/28 11:41:07 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.56 1999/10/06 06:38:04 inoue Exp $
*
*-------------------------------------------------------------------------
*/
@ -233,7 +233,7 @@ mdunlink(Relation reln)
int
mdextend(Relation reln, char *buffer)
{
long pos;
long pos, nbytes;
int nblocks;
MdfdVec *v;
@ -243,8 +243,22 @@ mdextend(Relation reln, char *buffer)
if ((pos = FileSeek(v->mdfd_vfd, 0L, SEEK_END)) < 0)
return SM_FAIL;
if (FileWrite(v->mdfd_vfd, buffer, BLCKSZ) != BLCKSZ)
if (pos % BLCKSZ != 0) /* the last block is incomplete */
{
pos -= pos % BLCKSZ;
if (FileSeek(v->mdfd_vfd, pos, SEEK_SET) < 0)
return SM_FAIL;
}
if ((nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ)) != BLCKSZ)
{
if (nbytes > 0)
{
FileTruncate(v->mdfd_vfd, pos);
FileSeek(v->mdfd_vfd, pos, SEEK_SET);
}
return SM_FAIL;
}
/* remember that we did a write, so we can sync at xact commit */
v->mdfd_flags |= MDFD_DIRTY;
@ -432,6 +446,8 @@ mdread(Relation reln, BlockNumber blocknum, char *buffer)
{
if (nbytes == 0)
MemSet(buffer, 0, BLCKSZ);
else if (blocknum == 0 && nbytes > 0 && mdnblocks(reln) == 0)
MemSet(buffer, 0, BLCKSZ);
else
status = SM_FAIL;
}
@ -1067,6 +1083,7 @@ _mdnblocks(File file, Size blcksz)
{
long len;
len = FileSeek(file, 0L, SEEK_END) - 1;
return (BlockNumber) ((len < 0) ? 0 : 1 + len / blcksz);
len = FileSeek(file, 0L, SEEK_END);
if (len < 0) return 0; /* on failure, assume file is empty */
return (BlockNumber) (len / blcksz);
}