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Clean up WAL/buffer interactions as per my recent proposal. Get rid of the

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misleadingly-named WriteBuffer routine, and instead require routines that
change buffer pages to call MarkBufferDirty (which does exactly what it says).
We also require that they do so before calling XLogInsert; this takes care of
the synchronization requirement documented in SyncOneBuffer.  Note that
because bufmgr takes the buffer content lock (in shared mode) while writing
out any buffer, it doesn't matter whether MarkBufferDirty is executed before
the buffer content change is complete, so long as the content change is
completed before releasing exclusive lock on the buffer.  So it's OK to set
the dirtybit before we fill in the LSN.
This eliminates the former kluge of needing to set the dirtybit in LockBuffer.
Aside from making the code more transparent, we can also add some new
debugging assertions, in particular that the caller of MarkBufferDirty must
hold the buffer content lock, not merely a pin.
This commit is contained in:
Tom Lane
2006-03-31 23:32:07 +00:00
parent 89395bfa6f
commit a8b8f4db23
24 changed files with 434 additions and 537 deletions
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72
src/backend/commands/vacuum.c
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@@ -13,7 +13,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.325 2006/03/05 15:58:25 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.326 2006/03/31 23:32:06 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -729,6 +729,8 @@ vac_update_relstats(Oid relid, BlockNumber num_pages, double num_tuples,
if (!hasindex)
pgcform->relhaspkey = false;
MarkBufferDirty(buffer);
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
@@ -739,8 +741,7 @@ vac_update_relstats(Oid relid, BlockNumber num_pages, double num_tuples,
*/
CacheInvalidateHeapTuple(rd, &rtup);
/* Write the buffer */
WriteBuffer(buffer);
ReleaseBuffer(buffer);
heap_close(rd, RowExclusiveLock);
}
@@ -795,11 +796,12 @@ vac_update_dbstats(Oid dbid,
dbform->datvacuumxid = vacuumXID;
dbform->datfrozenxid = frozenXID;
MarkBufferDirty(scan->rs_cbuf);
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
/* invalidate the tuple in the cache and write the buffer */
/* invalidate the tuple in the cache so we'll see the change in cache */
CacheInvalidateHeapTuple(relation, tuple);
WriteNoReleaseBuffer(scan->rs_cbuf);
heap_endscan(scan);
@@ -1298,6 +1300,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
relname, blkno)));
PageInit(page, BufferGetPageSize(buf), 0);
MarkBufferDirty(buf);
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_space += vacpage->free;
empty_pages++;
@@ -1305,8 +1308,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
vacpagecopy = copy_vac_page(vacpage);
vpage_insert(vacuum_pages, vacpagecopy);
vpage_insert(fraged_pages, vacpagecopy);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
UnlockReleaseBuffer(buf);
continue;
}
@@ -1321,8 +1323,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
vacpagecopy = copy_vac_page(vacpage);
vpage_insert(vacuum_pages, vacpagecopy);
vpage_insert(fraged_pages, vacpagecopy);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buf);
UnlockReleaseBuffer(buf);
continue;
}
@@ -1527,11 +1528,9 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
else
empty_end_pages = 0;
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
if (pgchanged)
WriteBuffer(buf);
else
ReleaseBuffer(buf);
MarkBufferDirty(buf);
UnlockReleaseBuffer(buf);
}
pfree(vacpage);
@@ -1682,7 +1681,6 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
OffsetNumber offnum,
maxoff;
bool isempty,
dowrite,
chain_tuple_moved;
vacuum_delay_point();
@@ -1714,8 +1712,6 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
isempty = PageIsEmpty(page);
dowrite = false;
/* Is the page in the vacuum_pages list? */
if (blkno == last_vacuum_block)
{
@@ -1726,7 +1722,6 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, last_vacuum_page);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
dowrite = true;
}
else
Assert(isempty);
@@ -1884,7 +1879,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
if (dst_buffer != InvalidBuffer)
{
WriteBuffer(dst_buffer);
ReleaseBuffer(dst_buffer);
dst_buffer = InvalidBuffer;
}
@@ -2148,8 +2143,8 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
else
keep_tuples++;
WriteBuffer(dst_buffer);
WriteBuffer(Cbuf);
ReleaseBuffer(dst_buffer);
ReleaseBuffer(Cbuf);
} /* end of move-the-tuple-chain loop */
dst_buffer = InvalidBuffer;
@@ -2166,7 +2161,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
{
if (dst_buffer != InvalidBuffer)
{
WriteBuffer(dst_buffer);
ReleaseBuffer(dst_buffer);
dst_buffer = InvalidBuffer;
}
for (i = 0; i < num_fraged_pages; i++)
@@ -2273,12 +2268,9 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
sizeof(OffsetNumber), vac_cmp_offno);
}
vpage_insert(&Nvacpagelist, copy_vac_page(vacpage));
WriteBuffer(buf);
}
else if (dowrite)
WriteBuffer(buf);
else
ReleaseBuffer(buf);
ReleaseBuffer(buf);
if (offnum <= maxoff)
break; /* had to quit early, see above note */
@@ -2290,7 +2282,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
if (dst_buffer != InvalidBuffer)
{
Assert(num_moved > 0);
WriteBuffer(dst_buffer);
ReleaseBuffer(dst_buffer);
}
if (num_moved > 0)
@@ -2332,8 +2324,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
page = BufferGetPage(buf);
if (!PageIsEmpty(page))
vacuum_page(onerel, buf, *curpage);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
UnlockReleaseBuffer(buf);
}
}
@@ -2449,6 +2440,8 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
uncnt = PageRepairFragmentation(page, unused);
MarkBufferDirty(buf);
/* XLOG stuff */
if (!onerel->rd_istemp)
{
@@ -2469,8 +2462,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
END_CRIT_SECTION();
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
UnlockReleaseBuffer(buf);
}
/* now - free new list of reaped pages */
@@ -2601,6 +2593,10 @@ move_chain_tuple(Relation rel,
newtup.t_data->t_ctid = *ctid;
*ctid = newtup.t_self;
MarkBufferDirty(dst_buf);
if (dst_buf != old_buf)
MarkBufferDirty(old_buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
@@ -2708,6 +2704,9 @@ move_plain_tuple(Relation rel,
old_tup->t_data->t_infomask |= HEAP_MOVED_OFF;
HeapTupleHeaderSetXvac(old_tup->t_data, myXID);
MarkBufferDirty(dst_buf);
MarkBufferDirty(old_buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
@@ -2832,8 +2831,8 @@ update_hint_bits(Relation rel, VacPageList fraged_pages, int num_fraged_pages,
else
htup->t_infomask |= HEAP_XMIN_INVALID;
}
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
MarkBufferDirty(buf);
UnlockReleaseBuffer(buf);
Assert((*curpage)->offsets_used == num_tuples);
checked_moved += num_tuples;
}
@@ -2867,8 +2866,7 @@ vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
buf = ReadBuffer(onerel, (*vacpage)->blkno);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
vacuum_page(onerel, buf, *vacpage);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
WriteBuffer(buf);
UnlockReleaseBuffer(buf);
}
}
@@ -2889,6 +2887,8 @@ vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
/*
* vacuum_page() -- free dead tuples on a page
* and repair its fragmentation.
*
* Caller must hold pin and lock on buffer.
*/
static void
vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
@@ -2912,6 +2912,8 @@ vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
uncnt = PageRepairFragmentation(page, unused);
MarkBufferDirty(buffer);
/* XLOG stuff */
if (!onerel->rd_istemp)
{