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Code Issues Releases Wiki Activity

New smgrtruncate smgr' interface func.

This commit is contained in:
Vadim B. Mikheev 1996-11-27 07:25:52 +00:00
parent a2a33e1344
commit 3385497228
1 changed files with 29 additions and 3 deletions
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32
src/backend/storage/smgr/smgr.c
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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/smgr.c,v 1.4 1996/11/08 05:59:15 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/smgr.c,v 1.5 1996/11/27 07:25:52 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -36,6 +36,7 @@ typedef struct f_smgr {
int (*smgr_flush)();
int (*smgr_blindwrt)();
int (*smgr_nblocks)();
int (*smgr_truncate)();
int (*smgr_commit)(); /* may be NULL */
int (*smgr_abort)(); /* may be NULL */
} f_smgr;
@ -49,12 +50,14 @@ static f_smgr smgrsw[] = {
/* magnetic disk */
{ mdinit, NULL, mdcreate, mdunlink, mdextend, mdopen, mdclose,
mdread, mdwrite, mdflush, mdblindwrt, mdnblocks, mdcommit, mdabort },
mdread, mdwrite, mdflush, mdblindwrt, mdnblocks, mdtruncate,
mdcommit, mdabort },
#ifdef MAIN_MEMORY
/* main memory */
{ mminit, mmshutdown, mmcreate, mmunlink, mmextend, mmopen, mmclose,
mmread, mmwrite, mmflush, mmblindwrt, mmnblocks, mmcommit, mmabort },
mmread, mmwrite, mmflush, mmblindwrt, mmnblocks, NULL,
mmcommit, mmabort },
#endif /* MAIN_MEMORY */
};
@ -321,6 +324,29 @@ smgrnblocks(int16 which, Relation reln)
return (nblocks);
}
/*
* smgrtruncate() -- Truncate supplied relation to a specified number
* of blocks
*
* Returns the number of blocks on success, aborts the current
* transaction on failure.
*/
int
smgrtruncate(int16 which, Relation reln, int nblocks)
{
int newblks;
newblks = nblocks;
if (smgrsw[which].smgr_truncate)
{
if ((newblks = (*(smgrsw[which].smgr_truncate))(reln, nblocks)) < 0)
elog(WARN, "cannot truncate %.*s to %d blocks",
NAMEDATALEN, &(reln->rd_rel->relname.data[0]), nblocks);
}
return (newblks);
}
/*
* smgrcommit(), smgrabort() -- Commit or abort changes made during the
* current transaction.