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Restructure local-buffer handling per recent pghackers discussion.

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The local buffer manager is no longer used for newly-created relations
(unless they are TEMP); a new non-TEMP relation goes through the shared
bufmgr and thus will participate normally in checkpoints.  But TEMP relations
use the local buffer manager throughout their lifespan.  Also, operations
in TEMP relations are not logged in WAL, thus improving performance.
Since it's no longer necessary to fsync relations as they move out of the
local buffers into shared buffers, quite a lot of smgr.c/md.c/fd.c code
is no longer needed and has been removed: there's no concept of a dirty
relation anymore in md.c/fd.c, and we never fsync anything but WAL.
Still TODO: improve local buffer management algorithms so that it would
be reasonable to increase NLocBuffer.
This commit is contained in:
Tom Lane
2002-08-06 02:36:35 +00:00
parent 35cd432b18
commit 5df307c778
28 changed files with 543 additions and 955 deletions
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166
src/backend/storage/smgr/md.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.91 2002/06/20 20:29:35 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/md.c,v 1.92 2002/08/06 02:36:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -381,16 +381,7 @@ mdclose_fd(int fd)
/* if not closed already */
if (v->mdfd_vfd >= 0)
{
/*
* We sync the file descriptor so that we don't need to reopen
* it at transaction commit to force changes to disk. (This
* is not really optional, because we are about to forget that
* the file even exists...)
*/
FileSync(v->mdfd_vfd);
FileClose(v->mdfd_vfd);
}
/* Now free vector */
v = v->mdfd_chain;
if (ov != &Md_fdvec[fd])
@@ -403,16 +394,7 @@ mdclose_fd(int fd)
if (v != (MdfdVec *) NULL)
{
if (v->mdfd_vfd >= 0)
{
/*
* We sync the file descriptor so that we don't need to reopen
* it at transaction commit to force changes to disk. (This
* is not really optional, because we are about to forget that
* the file even exists...)
*/
FileSync(v->mdfd_vfd);
FileClose(v->mdfd_vfd);
}
}
#endif
@@ -497,56 +479,16 @@ mdwrite(Relation reln, BlockNumber blocknum, char *buffer)
return SM_SUCCESS;
}
/*
* mdflush() -- Synchronously write a block to disk.
*
* This is exactly like mdwrite(), but doesn't return until the file
* system buffer cache has been flushed.
*/
int
mdflush(Relation reln, BlockNumber blocknum, char *buffer)
{
int status;
long seekpos;
MdfdVec *v;
v = _mdfd_getseg(reln, blocknum);
#ifndef LET_OS_MANAGE_FILESIZE
seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
#ifdef DIAGNOSTIC
if (seekpos >= BLCKSZ * RELSEG_SIZE)
elog(FATAL, "seekpos too big!");
#endif
#else
seekpos = (long) (BLCKSZ * (blocknum));
#endif
if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
return SM_FAIL;
/* write and sync the block */
status = SM_SUCCESS;
if (FileWrite(v->mdfd_vfd, buffer, BLCKSZ) != BLCKSZ
|| FileSync(v->mdfd_vfd) < 0)
status = SM_FAIL;
return status;
}
/*
* mdblindwrt() -- Write a block to disk blind.
*
* We have to be able to do this using only the name and OID of
* the database and relation in which the block belongs. Otherwise
* this is much like mdwrite(). If dofsync is TRUE, then we fsync
* the file, making it more like mdflush().
* We have to be able to do this using only the rnode of the relation
* in which the block belongs. Otherwise this is much like mdwrite().
*/
int
mdblindwrt(RelFileNode rnode,
BlockNumber blkno,
char *buffer,
bool dofsync)
char *buffer)
{
int status;
long seekpos;
@@ -568,7 +510,6 @@ mdblindwrt(RelFileNode rnode,
#endif
errno = 0;
if (lseek(fd, seekpos, SEEK_SET) != seekpos)
{
elog(LOG, "mdblindwrt: lseek(%ld) failed: %m", seekpos);
@@ -578,7 +519,7 @@ mdblindwrt(RelFileNode rnode,
status = SM_SUCCESS;
/* write and optionally sync the block */
/* write the block */
errno = 0;
if (write(fd, buffer, BLCKSZ) != BLCKSZ)
{
@@ -598,54 +539,6 @@ mdblindwrt(RelFileNode rnode,
return status;
}
/*
* mdmarkdirty() -- Mark the specified block "dirty" (ie, needs fsync).
*
* Returns SM_SUCCESS or SM_FAIL.
*/
int
mdmarkdirty(Relation reln, BlockNumber blkno)
{
MdfdVec *v;
v = _mdfd_getseg(reln, blkno);
FileMarkDirty(v->mdfd_vfd);
return SM_SUCCESS;
}
/*
* mdblindmarkdirty() -- Mark the specified block "dirty" (ie, needs fsync).
*
* We have to be able to do this using only the name and OID of
* the database and relation in which the block belongs. Otherwise
* this is much like mdmarkdirty(). However, we do the fsync immediately
* rather than building md/fd datastructures to postpone it till later.
*/
int
mdblindmarkdirty(RelFileNode rnode,
BlockNumber blkno)
{
int status;
int fd;
fd = _mdfd_blind_getseg(rnode, blkno);
if (fd < 0)
return SM_FAIL;
status = SM_SUCCESS;
if (pg_fsync(fd) < 0)
status = SM_FAIL;
if (close(fd) < 0)
status = SM_FAIL;
return status;
}
/*
* mdnblocks() -- Get the number of blocks stored in a relation.
*
@@ -796,61 +689,36 @@ mdtruncate(Relation reln, BlockNumber nblocks)
/*
* mdcommit() -- Commit a transaction.
*
* All changes to magnetic disk relations must be forced to stable
* storage. This routine makes a pass over the private table of
* file descriptors. Any descriptors to which we have done writes,
* but not synced, are synced here.
*
* Returns SM_SUCCESS or SM_FAIL with errno set as appropriate.
*/
int
mdcommit()
mdcommit(void)
{
int i;
MdfdVec *v;
for (i = 0; i < CurFd; i++)
{
v = &Md_fdvec[i];
if (v->mdfd_flags & MDFD_FREE)
continue;
/* Sync the file entry */
#ifndef LET_OS_MANAGE_FILESIZE
for (; v != (MdfdVec *) NULL; v = v->mdfd_chain)
#else
if (v != (MdfdVec *) NULL)
#endif
{
if (FileSync(v->mdfd_vfd) < 0)
return SM_FAIL;
}
}
/*
* We don't actually have to do anything here...
*/
return SM_SUCCESS;
}
/*
* mdabort() -- Abort a transaction.
*
* Changes need not be forced to disk at transaction abort. We mark
* all file descriptors as clean here. Always returns SM_SUCCESS.
* Changes need not be forced to disk at transaction abort.
*/
int
mdabort()
mdabort(void)
{
/*
* We don't actually have to do anything here. fd.c will discard
* fsync-needed bits in its AtEOXact_Files() routine.
* We don't actually have to do anything here...
*/
return SM_SUCCESS;
}
/*
* mdsync() -- Sync storage.
*
* mdsync() -- Sync previous writes to stable storage.
*/
int
mdsync()
mdsync(void)
{
sync();
if (IsUnderPostmaster)
@@ -861,11 +729,9 @@ mdsync()
/*
* _fdvec_alloc () -- grab a free (or new) md file descriptor vector.
*
*/
static
int
_fdvec_alloc()
static int
_fdvec_alloc(void)
{
MdfdVec *nvec;
int fdvec,