/*
* smgrtruncate() -- Truncate supplied relation to the specified number
* of blocks
*
* The truncation is done immediately, so this can't be rolled back.
*/
void
smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
{
/*
* Get rid of any buffers for the about-to-be-deleted blocks. bufmgr will
* just drop them without bothering to write the contents.
*/
DropRelFileNodeBuffers(reln->smgr_rnode, forknum, nblocks);
/*
* Send a shared-inval message to force other backends to close any smgr
* references they may have for this rel. This is useful because they
* might have open file pointers to segments that got removed, and/or
* smgr_targblock variables pointing past the new rel end. (The inval
* message will come back to our backend, too, causing a
* probably-unnecessary local smgr flush. But we don't expect that this
* is a performance-critical path.) As in the unlink code, we want to be
* sure the message is sent before we start changing things on-disk.
*/
CacheInvalidateSmgr(reln->smgr_rnode);
/*
* Do the truncation.
*/
(*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, forknum, nblocks);
}
/*
* Shared subroutine that actually does the unlink ...
*/
static void
smgr_internal_unlink(RelFileNode rnode, int which, bool isTemp, bool isRedo)
{
/*
* Get rid of any remaining buffers for the relation. bufmgr will just
* drop them without bothering to write the contents.
*/
DropRelFileNodeBuffers(rnode, isTemp, 0);
/*
* Tell the free space map to forget this relation. It won't be accessed
* any more anyway, but we may as well recycle the map space quickly.
*/
FreeSpaceMapForgetRel(&rnode);
/*
* And delete the physical files.
*
* Note: we treat deletion failure as a WARNING, not an error, because
* we've already decided to commit or abort the current xact.
*/
if (!(*(smgrsw[which].smgr_unlink)) (rnode, isRedo))
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove relation %u/%u/%u: %m",
rnode.spcNode,
rnode.dbNode,
rnode.relNode)));
}
void
smgr_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
if (info == XLOG_SMGR_CREATE)
{
xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
SMgrRelation reln;
reln = smgropen(xlrec->rnode);
smgrcreate(reln, false, true);
}
else if (info == XLOG_SMGR_TRUNCATE)
{
xl_smgr_truncate *xlrec = (xl_smgr_truncate *) XLogRecGetData(record);
SMgrRelation reln;
BlockNumber newblks;
reln = smgropen(xlrec->rnode);
/* Can't use smgrtruncate because it would try to xlog */
/*
* First, force bufmgr to drop any buffers it has for the to-be-
* truncated blocks. We must do this, else subsequent XLogReadBuffer
* operations will not re-extend the file properly.
*/
DropRelFileNodeBuffers(xlrec->rnode, false, xlrec->blkno);
/*
* Tell the free space map to forget anything it may have stored for
* the about-to-be-deleted blocks. We want to be sure it won't return
* bogus block numbers later on.
*/
FreeSpaceMapTruncateRel(&reln->smgr_rnode, xlrec->blkno);
/* Do the truncation */
newblks = (*(smgrsw[reln->smgr_which].smgr_truncate)) (reln,
xlrec->blkno,
false);
if (newblks == InvalidBlockNumber)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
reln->smgr_rnode.spcNode,
reln->smgr_rnode.dbNode,
reln->smgr_rnode.relNode,
xlrec->blkno)));
/* Also tell xlogutils.c about it */
XLogTruncateRelation(xlrec->rnode, xlrec->blkno);
}
else
elog(PANIC, "smgr_redo: unknown op code %u", info);
}
/*
* smgrtruncate() -- Truncate supplied relation to the specified number
* of blocks
*
* Returns the number of blocks on success, aborts the current
* transaction on failure.
*/
BlockNumber
smgrtruncate(SMgrRelation reln, BlockNumber nblocks, bool isTemp)
{
BlockNumber newblks;
/*
* Get rid of any buffers for the about-to-be-deleted blocks. bufmgr will
* just drop them without bothering to write the contents.
*/
DropRelFileNodeBuffers(reln->smgr_rnode, isTemp, nblocks);
/*
* Tell the free space map to forget anything it may have stored for the
* about-to-be-deleted blocks. We want to be sure it won't return bogus
* block numbers later on.
*/
FreeSpaceMapTruncateRel(&reln->smgr_rnode, nblocks);
/* Do the truncation */
newblks = (*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, nblocks,
isTemp);
if (newblks == InvalidBlockNumber)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
reln->smgr_rnode.spcNode,
reln->smgr_rnode.dbNode,
reln->smgr_rnode.relNode,
nblocks)));
if (!isTemp)
{
/*
* Make a non-transactional XLOG entry showing the file truncation.
* It's non-transactional because we should replay it whether the
* transaction commits or not; the underlying file change is certainly
* not reversible.
*/
XLogRecPtr lsn;
XLogRecData rdata;
xl_smgr_truncate xlrec;
xlrec.blkno = newblks;
xlrec.rnode = reln->smgr_rnode;
rdata.data = (char *) &xlrec;
rdata.len = sizeof(xlrec);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_TRUNCATE | XLOG_NO_TRAN,
&rdata);
}
return newblks;
}
/*
* smgrdounlinkfork() -- Immediately unlink one fork of a relation.
*
* The specified fork of the relation is removed from the store. This
* should not be used during transactional operations, since it can't be
* undone.
*
* If isRedo is true, it is okay for the underlying file to be gone
* already.
*/
void
smgrdounlinkfork(SMgrRelation reln, ForkNumber forknum, bool isRedo)
{
RelFileNodeBackend rnode = reln->smgr_rnode;
int which = reln->smgr_which;
/* Close the fork at smgr level */
(*(smgrsw[which].smgr_close)) (reln, forknum);
/*
* Get rid of any remaining buffers for the fork. bufmgr will just drop
* them without bothering to write the contents.
*/
DropRelFileNodeBuffers(rnode, forknum, 0);
/*
* It'd be nice to tell the stats collector to forget it immediately, too.
* But we can't because we don't know the OID (and in cases involving
* relfilenode swaps, it's not always clear which table OID to forget,
* anyway).
*/
/*
* Send a shared-inval message to force other backends to close any
* dangling smgr references they may have for this rel. We should do this
* before starting the actual unlinking, in case we fail partway through
* that step. Note that the sinval message will eventually come back to
* this backend, too, and thereby provide a backstop that we closed our
* own smgr rel.
*/
CacheInvalidateSmgr(rnode);
/*
* Delete the physical file(s).
*
* Note: smgr_unlink must treat deletion failure as a WARNING, not an
* ERROR, because we've already decided to commit or abort the current
* xact.
*/
(*(smgrsw[which].smgr_unlink)) (rnode, forknum, isRedo);
}
/*
* Shared subroutine that actually does the unlink ...
*/
static void
smgr_internal_unlink(RelFileNode rnode, int which, bool isTemp, bool isRedo)
{
/*
* Get rid of any remaining buffers for the relation. bufmgr will just
* drop them without bothering to write the contents.
*/
DropRelFileNodeBuffers(rnode, isTemp, 0);
/*
* Tell the free space map to forget this relation. It won't be accessed
* any more anyway, but we may as well recycle the map space quickly.
*/
FreeSpaceMapForgetRel(&rnode);
/*
* Tell the stats collector to forget it immediately, too. Skip this in
* recovery mode, since the stats collector likely isn't running (and if
* it is, pgstat.c will get confused because we aren't a real backend
* process).
*/
if (!InRecovery)
pgstat_drop_relation(rnode.relNode);
/*
* And delete the physical files.
*
* Note: we treat deletion failure as a WARNING, not an error, because
* we've already decided to commit or abort the current xact.
*/
if (!(*(smgrsw[which].smgr_unlink)) (rnode, isRedo))
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove relation %u/%u/%u: %m",
rnode.spcNode,
rnode.dbNode,
rnode.relNode)));
}
