Derive latestRemovedXid for btree deletes by reading heap pages. The

WAL record for btree delete contains a list of tids, even when backup
blocks are present. We follow the tids to their heap tuples, taking
care to follow LP_REDIRECT tuples. We ignore LP_DEAD tuples on the
understanding that they will always have xmin/xmax earlier than any
LP_NORMAL tuples referred to by killed index tuples. Iff all tuples
are LP_DEAD we return InvalidTransactionId. The heap relfilenode is
added to the WAL record, requiring API changes to pass down the heap
Relation. XLOG_PAGE_MAGIC updated.
This commit is contained in:
Simon Riggs 2010-03-28 09:27:02 +00:00
parent 59292f28ca
commit a760893dbd
6 changed files with 254 additions and 71 deletions

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.177 2010/02/26 02:00:34 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.178 2010/03/28 09:27:01 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@ -57,7 +57,8 @@ static void _bt_findinsertloc(Relation rel,
OffsetNumber *offsetptr,
int keysz,
ScanKey scankey,
IndexTuple newtup);
IndexTuple newtup,
Relation heapRel);
static void _bt_insertonpg(Relation rel, Buffer buf,
BTStack stack,
IndexTuple itup,
@ -78,7 +79,7 @@ static void _bt_pgaddtup(Relation rel, Page page,
OffsetNumber itup_off, const char *where);
static bool _bt_isequal(TupleDesc itupdesc, Page page, OffsetNumber offnum,
int keysz, ScanKey scankey);
static void _bt_vacuum_one_page(Relation rel, Buffer buffer);
static void _bt_vacuum_one_page(Relation rel, Buffer buffer, Relation heapRel);
/*
@ -175,7 +176,7 @@ top:
if (checkUnique != UNIQUE_CHECK_EXISTING)
{
/* do the insertion */
_bt_findinsertloc(rel, &buf, &offset, natts, itup_scankey, itup);
_bt_findinsertloc(rel, &buf, &offset, natts, itup_scankey, itup, heapRel);
_bt_insertonpg(rel, buf, stack, itup, offset, false);
}
else
@ -491,7 +492,8 @@ _bt_findinsertloc(Relation rel,
OffsetNumber *offsetptr,
int keysz,
ScanKey scankey,
IndexTuple newtup)
IndexTuple newtup,
Relation heapRel)
{
Buffer buf = *bufptr;
Page page = BufferGetPage(buf);
@ -556,7 +558,7 @@ _bt_findinsertloc(Relation rel,
*/
if (P_ISLEAF(lpageop) && P_HAS_GARBAGE(lpageop))
{
_bt_vacuum_one_page(rel, buf);
_bt_vacuum_one_page(rel, buf, heapRel);
/*
* remember that we vacuumed this page, because that makes the
@ -1998,7 +2000,7 @@ _bt_isequal(TupleDesc itupdesc, Page page, OffsetNumber offnum,
* super-exclusive "cleanup" lock (see nbtree/README).
*/
static void
_bt_vacuum_one_page(Relation rel, Buffer buffer)
_bt_vacuum_one_page(Relation rel, Buffer buffer, Relation heapRel)
{
OffsetNumber deletable[MaxOffsetNumber];
int ndeletable = 0;
@ -2025,7 +2027,7 @@ _bt_vacuum_one_page(Relation rel, Buffer buffer)
}
if (ndeletable > 0)
_bt_delitems(rel, buffer, deletable, ndeletable, false, 0);
_bt_delitems_delete(rel, buffer, deletable, ndeletable, heapRel);
/*
* Note: if we didn't find any LP_DEAD items, then the page's

View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.121 2010/03/19 10:41:21 sriggs Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.122 2010/03/28 09:27:01 sriggs Exp $
*
* NOTES
* Postgres btree pages look like ordinary relation pages. The opaque
@ -719,15 +719,12 @@ _bt_page_recyclable(Page page)
* ensure correct locking.
*/
void
_bt_delitems(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, bool isVacuum,
BlockNumber lastBlockVacuumed)
_bt_delitems_vacuum(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, BlockNumber lastBlockVacuumed)
{
Page page = BufferGetPage(buf);
BTPageOpaque opaque;
Assert(isVacuum || lastBlockVacuumed == 0);
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
@ -759,35 +756,14 @@ _bt_delitems(Relation rel, Buffer buf,
XLogRecPtr recptr;
XLogRecData rdata[2];
if (isVacuum)
{
xl_btree_vacuum xlrec_vacuum;
xl_btree_vacuum xlrec_vacuum;
xlrec_vacuum.node = rel->rd_node;
xlrec_vacuum.block = BufferGetBlockNumber(buf);
xlrec_vacuum.lastBlockVacuumed = lastBlockVacuumed;
rdata[0].data = (char *) &xlrec_vacuum;
rdata[0].len = SizeOfBtreeVacuum;
}
else
{
xl_btree_delete xlrec_delete;
xlrec_delete.node = rel->rd_node;
xlrec_delete.block = BufferGetBlockNumber(buf);
/*
* XXX: We would like to set an accurate latestRemovedXid, but
* there is no easy way of obtaining a useful value. So we punt
* and store InvalidTransactionId, which forces the standby to
* wait for/cancel all currently running transactions.
*/
xlrec_delete.latestRemovedXid = InvalidTransactionId;
rdata[0].data = (char *) &xlrec_delete;
rdata[0].len = SizeOfBtreeDelete;
}
xlrec_vacuum.node = rel->rd_node;
xlrec_vacuum.block = BufferGetBlockNumber(buf);
xlrec_vacuum.lastBlockVacuumed = lastBlockVacuumed;
rdata[0].data = (char *) &xlrec_vacuum;
rdata[0].len = SizeOfBtreeVacuum;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
@ -810,10 +786,82 @@ _bt_delitems(Relation rel, Buffer buf,
rdata[1].buffer_std = true;
rdata[1].next = NULL;
if (isVacuum)
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_VACUUM, rdata);
else
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_DELETE, rdata);
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_VACUUM, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
}
void
_bt_delitems_delete(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, Relation heapRel)
{
Page page = BufferGetPage(buf);
BTPageOpaque opaque;
Assert(nitems > 0);
/* No ereport(ERROR) until changes are logged */
START_CRIT_SECTION();
/* Fix the page */
PageIndexMultiDelete(page, itemnos, nitems);
/*
* We can clear the vacuum cycle ID since this page has certainly been
* processed by the current vacuum scan.
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
opaque->btpo_cycleid = 0;
/*
* Mark the page as not containing any LP_DEAD items. This is not
* certainly true (there might be some that have recently been marked, but
* weren't included in our target-item list), but it will almost always be
* true and it doesn't seem worth an additional page scan to check it.
* Remember that BTP_HAS_GARBAGE is only a hint anyway.
*/
opaque->btpo_flags &= ~BTP_HAS_GARBAGE;
MarkBufferDirty(buf);
/* XLOG stuff */
if (!rel->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData rdata[3];
xl_btree_delete xlrec_delete;
xlrec_delete.node = rel->rd_node;
xlrec_delete.hnode = heapRel->rd_node;
xlrec_delete.block = BufferGetBlockNumber(buf);
xlrec_delete.nitems = nitems;
rdata[0].data = (char *) &xlrec_delete;
rdata[0].len = SizeOfBtreeDelete;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* We need the target-offsets array whether or not we store the
* to allow us to find the latestRemovedXid on a standby server.
*/
rdata[1].data = (char *) itemnos;
rdata[1].len = nitems * sizeof(OffsetNumber);
rdata[1].buffer = InvalidBuffer;
rdata[1].next = &(rdata[2]);
rdata[2].data = NULL;
rdata[2].len = 0;
rdata[2].buffer = buf;
rdata[2].buffer_std = true;
rdata[2].next = NULL;
recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_DELETE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);

View File

@ -12,7 +12,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.176 2010/02/26 02:00:34 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.177 2010/03/28 09:27:01 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@ -708,7 +708,7 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
buf = ReadBufferExtended(rel, MAIN_FORKNUM, num_pages - 1, RBM_NORMAL,
info->strategy);
LockBufferForCleanup(buf);
_bt_delitems(rel, buf, NULL, 0, true, vstate.lastBlockVacuumed);
_bt_delitems_vacuum(rel, buf, NULL, 0, vstate.lastBlockVacuumed);
_bt_relbuf(rel, buf);
}
@ -889,7 +889,7 @@ restart:
{
BlockNumber lastBlockVacuumed = BufferGetBlockNumber(buf);
_bt_delitems(rel, buf, deletable, ndeletable, true, vstate->lastBlockVacuumed);
_bt_delitems_vacuum(rel, buf, deletable, ndeletable, vstate->lastBlockVacuumed);
/*
* Keep track of the block number of the lastBlockVacuumed, so we

View File

@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.63 2010/03/19 10:41:22 sriggs Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.64 2010/03/28 09:27:01 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@ -553,6 +553,139 @@ btree_xlog_vacuum(XLogRecPtr lsn, XLogRecord *record)
UnlockReleaseBuffer(buffer);
}
/*
* Get the latestRemovedXid from the heap pages pointed at by the index
* tuples being deleted. This puts the work for calculating latestRemovedXid
* into the recovery path rather than the primary path.
*
* It's possible that this generates a fair amount of I/O, since an index
* block may have hundreds of tuples being deleted. Repeat accesses to the
* same heap blocks are common, though are not yet optimised.
*
* XXX optimise later with something like XLogPrefetchBuffer()
*/
static TransactionId
btree_xlog_delete_get_latestRemovedXid(XLogRecord *record)
{
OffsetNumber *unused;
Buffer ibuffer, hbuffer;
Page ipage, hpage;
ItemId iitemid, hitemid;
IndexTuple itup;
HeapTupleHeader htuphdr;
BlockNumber hblkno;
OffsetNumber hoffnum;
TransactionId latestRemovedXid = InvalidTransactionId;
TransactionId htupxid = InvalidTransactionId;
int i;
int num_unused, num_redirect, num_dead;
xl_btree_delete *xlrec = (xl_btree_delete *) XLogRecGetData(record);
/*
* Get index page
*/
ibuffer = XLogReadBuffer(xlrec->node, xlrec->block, false);
if (!BufferIsValid(ibuffer))
return InvalidTransactionId;
ipage = (Page) BufferGetPage(ibuffer);
/*
* Loop through the deleted index items to obtain the TransactionId
* from the heap items they point to.
*/
unused = (OffsetNumber *) ((char *) xlrec + SizeOfBtreeDelete);
for (i = 0; i < xlrec->nitems; i++)
{
/*
* Identify the index tuple about to be deleted
*/
iitemid = PageGetItemId(ipage, unused[i]);
itup = (IndexTuple) PageGetItem(ipage, iitemid);
/*
* Locate the heap page that the index tuple points at
*/
hblkno = ItemPointerGetBlockNumber(&(itup->t_tid));
hbuffer = XLogReadBuffer(xlrec->hnode, hblkno, false);
if (!BufferIsValid(hbuffer))
{
UnlockReleaseBuffer(ibuffer);
return InvalidTransactionId;
}
hpage = (Page) BufferGetPage(hbuffer);
/*
* Look up the heap tuple header that the index tuple points at
* by using the heap node supplied with the xlrec. We can't use
* heap_fetch, since it uses ReadBuffer rather than XLogReadBuffer.
* Note that we are not looking at tuple data here, just headers.
*/
hoffnum = ItemPointerGetOffsetNumber(&(itup->t_tid));
hitemid = PageGetItemId(hpage, hoffnum);
/*
* Follow any redirections until we find something useful.
*/
while (ItemIdIsRedirected(hitemid))
{
num_redirect++;
hoffnum = ItemIdGetRedirect(hitemid);
hitemid = PageGetItemId(hpage, hoffnum);
CHECK_FOR_INTERRUPTS();
}
/*
* If the heap item has storage, then read the header. Some LP_DEAD
* items may not be accessible, so we ignore them.
*/
if (ItemIdHasStorage(hitemid))
{
htuphdr = (HeapTupleHeader) PageGetItem(hpage, hitemid);
/*
* Get the heap tuple's xmin/xmax and ratchet up the latestRemovedXid.
* No need to consider xvac values here.
*/
htupxid = HeapTupleHeaderGetXmin(htuphdr);
if (TransactionIdFollows(htupxid, latestRemovedXid))
latestRemovedXid = htupxid;
htupxid = HeapTupleHeaderGetXmax(htuphdr);
if (TransactionIdFollows(htupxid, latestRemovedXid))
latestRemovedXid = htupxid;
}
else if (ItemIdIsDead(hitemid))
{
/*
* Conjecture: if hitemid is dead then it had xids before the xids
* marked on LP_NORMAL items. So we just ignore this item and move
* onto the next, for the purposes of calculating latestRemovedxids.
*/
num_dead++;
}
else
{
Assert(!ItemIdIsUsed(hitemid));
num_unused++;
}
UnlockReleaseBuffer(hbuffer);
}
UnlockReleaseBuffer(ibuffer);
Assert(num_unused == 0);
/*
* Note that if all heap tuples were LP_DEAD then we will be
* returning InvalidTransactionId here. This seems very unlikely
* in practice.
*/
return latestRemovedXid;
}
static void
btree_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
{
@ -584,12 +717,10 @@ btree_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
if (record->xl_len > SizeOfBtreeDelete)
{
OffsetNumber *unused;
OffsetNumber *unend;
unused = (OffsetNumber *) ((char *) xlrec + SizeOfBtreeDelete);
unend = (OffsetNumber *) ((char *) xlrec + record->xl_len);
PageIndexMultiDelete(page, unused, unend - unused);
PageIndexMultiDelete(page, unused, xlrec->nitems);
}
/*
@ -830,6 +961,7 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record)
* from individual btree vacuum records on that index.
*/
{
TransactionId latestRemovedXid = btree_xlog_delete_get_latestRemovedXid(record);
xl_btree_delete *xlrec = (xl_btree_delete *) XLogRecGetData(record);
/*
@ -839,7 +971,7 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record)
* here is worth some thought and possibly some effort to
* improve.
*/
ResolveRecoveryConflictWithSnapshot(xlrec->latestRemovedXid, xlrec->node);
ResolveRecoveryConflictWithSnapshot(latestRemovedXid, xlrec->node);
}
break;
@ -1012,10 +1144,10 @@ btree_desc(StringInfo buf, uint8 xl_info, char *rec)
{
xl_btree_delete *xlrec = (xl_btree_delete *) rec;
appendStringInfo(buf, "delete: rel %u/%u/%u; blk %u, latestRemovedXid %u",
xlrec->node.spcNode, xlrec->node.dbNode,
xlrec->node.relNode, xlrec->block,
xlrec->latestRemovedXid);
appendStringInfo(buf, "delete: index %u/%u/%u; iblk %u, heap %u/%u/%u;",
xlrec->node.spcNode, xlrec->node.dbNode, xlrec->node.relNode,
xlrec->block,
xlrec->hnode.spcNode, xlrec->hnode.dbNode, xlrec->hnode.relNode);
break;
}
case XLOG_BTREE_DELETE_PAGE:

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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.133 2010/03/20 07:49:48 sriggs Exp $
* $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.134 2010/03/28 09:27:02 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@ -314,14 +314,15 @@ typedef struct xl_btree_split
*/
typedef struct xl_btree_delete
{
RelFileNode node;
RelFileNode node; /* RelFileNode of the index */
BlockNumber block;
TransactionId latestRemovedXid;
RelFileNode hnode; /* RelFileNode of the heap the index currently points at */
int nitems;
/* TARGET OFFSET NUMBERS FOLLOW AT THE END */
} xl_btree_delete;
#define SizeOfBtreeDelete (offsetof(xl_btree_delete, latestRemovedXid) + sizeof(TransactionId))
#define SizeOfBtreeDelete (offsetof(xl_btree_delete, nitems) + sizeof(int))
/*
* This is what we need to know about page reuse within btree.
@ -349,13 +350,12 @@ typedef struct xl_btree_reuse_page
* heap tuples.
*
* Any changes to any one block are registered on just one WAL record. All
* blocks that we need to run EnsureBlockUnpinned() before we touch the changed
* block are also given on this record as a variable length array. The array
* is compressed by way of storing an array of block ranges, rather than an
* actual array of blockids.
* blocks that we need to run EnsureBlockUnpinned() are listed as a block range
* starting from the last block vacuumed through until this one. Individual
* block numbers aren't given.
*
* Note that the *last* WAL record in any vacuum of an index is allowed to
* have numItems == 0. All other WAL records must have numItems > 0.
* have a zero length array of offsets. Earlier records must have at least one.
*/
typedef struct xl_btree_vacuum
{
@ -588,9 +588,10 @@ extern Buffer _bt_relandgetbuf(Relation rel, Buffer obuf,
extern void _bt_relbuf(Relation rel, Buffer buf);
extern void _bt_pageinit(Page page, Size size);
extern bool _bt_page_recyclable(Page page);
extern void _bt_delitems(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, bool isVacuum,
BlockNumber lastBlockVacuumed);
extern void _bt_delitems_delete(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, Relation heapRel);
extern void _bt_delitems_vacuum(Relation rel, Buffer buf,
OffsetNumber *itemnos, int nitems, BlockNumber lastBlockVacuumed);
extern int _bt_pagedel(Relation rel, Buffer buf, BTStack stack);
/*

View File

@ -11,7 +11,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/xlog_internal.h,v 1.30 2010/03/19 17:42:10 sriggs Exp $
* $PostgreSQL: pgsql/src/include/access/xlog_internal.h,v 1.31 2010/03/28 09:27:02 sriggs Exp $
*/
#ifndef XLOG_INTERNAL_H
#define XLOG_INTERNAL_H
@ -71,7 +71,7 @@ typedef struct XLogContRecord
/*
* Each page of XLOG file has a header like this:
*/
#define XLOG_PAGE_MAGIC 0x9002 /* can be used as WAL version indicator */
#define XLOG_PAGE_MAGIC 0x9003 /* can be used as WAL version indicator */
typedef struct XLogPageHeaderData
{