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New mdtruncate() func for single segment relations (< 2Gb).

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This commit is contained in:
Vadim B. Mikheev 1996-11-27 07:24:02 +00:00
parent 3643248ae2
commit a2a33e1344
1 changed files with 31 additions and 1 deletions
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32
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 1.9 1996/11/25 06:33:51 bryanh Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.10 1996/11/27 07:24:02 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -528,6 +528,36 @@ mdnblocks(Relation reln)
}
}
/*
* mdtruncate() -- Truncate relation to specified number of blocks.
*
* Returns # of blocks or -1 on error.
*/
int
mdtruncate (Relation reln, int nblocks)
{
int fd;
MdfdVec *v;
int curnblk;
curnblk = mdnblocks (reln);
if ( curnblk / RELSEG_SIZE > 0 )
{
elog (NOTICE, "Can't truncate multi-segments relation %.*s",
NAMEDATALEN, &(reln->rd_rel->relname.data[0]));
return (curnblk);
}
fd = RelationGetFile(reln);
v = &Md_fdvec[fd];
if ( FileTruncate (v->mdfd_vfd, nblocks * BLCKSZ) < 0 )
return (-1);
return (nblocks);
} /* mdtruncate */
/*
* mdcommit() -- Commit a transaction.
*