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postgres/src/backend/access/heap/heapam.c
Tom Lane b3005276eb Decouple the values of TOAST_TUPLE_THRESHOLD and TOAST_MAX_CHUNK_SIZE. 
Add the latter to the values checked in pg_control, since it can't be changed
without invalidating toast table content.  This commit in itself shouldn't
change any behavior, but it lays some necessary groundwork for experimentation
with these toast-control numbers.

Note: while TOAST_TUPLE_THRESHOLD can now be changed without initdb, some
thought still needs to be given to needs_toast_table() in toasting.c before
unleashing random changes.
2007-04-03 04:14:26 +00:00

4043 lines
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/*-------------------------------------------------------------------------
*
* heapam.c
* heap access method code
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.231 2007/04/03 04:14:26 tgl Exp $
*
*
* INTERFACE ROUTINES
* relation_open - open any relation by relation OID
* relation_openrv - open any relation specified by a RangeVar
* relation_close - close any relation
* heap_open - open a heap relation by relation OID
* heap_openrv - open a heap relation specified by a RangeVar
* heap_close - (now just a macro for relation_close)
* heap_beginscan - begin relation scan
* heap_rescan - restart a relation scan
* heap_endscan - end relation scan
* heap_getnext - retrieve next tuple in scan
* heap_fetch - retrieve tuple with given tid
* heap_insert - insert tuple into a relation
* heap_delete - delete a tuple from a relation
* heap_update - replace a tuple in a relation with another tuple
* heap_markpos - mark scan position
* heap_restrpos - restore position to marked location
* heap_sync - sync heap, for when no WAL has been written
*
* NOTES
* This file contains the heap_ routines which implement
* the POSTGRES heap access method used for all POSTGRES
* relations.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "access/hio.h"
#include "access/multixact.h"
#include "access/transam.h"
#include "access/tuptoaster.h"
#include "access/valid.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/namespace.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf,
ItemPointerData from, Buffer newbuf, HeapTuple newtup, bool move);
/* ----------------------------------------------------------------
* heap support routines
* ----------------------------------------------------------------
*/
/* ----------------
* initscan - scan code common to heap_beginscan and heap_rescan
* ----------------
*/
static void
initscan(HeapScanDesc scan, ScanKey key)
{
/*
* Determine the number of blocks we have to scan.
*
* It is sufficient to do this once at scan start, since any tuples added
* while the scan is in progress will be invisible to my transaction
* anyway...
*/
scan->rs_nblocks = RelationGetNumberOfBlocks(scan->rs_rd);
scan->rs_inited = false;
scan->rs_ctup.t_data = NULL;
ItemPointerSetInvalid(&scan->rs_ctup.t_self);
scan->rs_cbuf = InvalidBuffer;
scan->rs_cblock = InvalidBlockNumber;
/* we don't have a marked position... */
ItemPointerSetInvalid(&(scan->rs_mctid));
/* page-at-a-time fields are always invalid when not rs_inited */
/*
* copy the scan key, if appropriate
*/
if (key != NULL)
memcpy(scan->rs_key, key, scan->rs_nkeys * sizeof(ScanKeyData));
pgstat_count_heap_scan(&scan->rs_pgstat_info);
}
/*
* heapgetpage - subroutine for heapgettup()
*
* This routine reads and pins the specified page of the relation.
* In page-at-a-time mode it performs additional work, namely determining
* which tuples on the page are visible.
*/
static void
heapgetpage(HeapScanDesc scan, BlockNumber page)
{
Buffer buffer;
Snapshot snapshot;
Page dp;
int lines;
int ntup;
OffsetNumber lineoff;
ItemId lpp;
Assert(page < scan->rs_nblocks);
scan->rs_cbuf = ReleaseAndReadBuffer(scan->rs_cbuf,
scan->rs_rd,
page);
scan->rs_cblock = page;
if (!scan->rs_pageatatime)
return;
buffer = scan->rs_cbuf;
snapshot = scan->rs_snapshot;
/*
* We must hold share lock on the buffer content while examining tuple
* visibility. Afterwards, however, the tuples we have found to be
* visible are guaranteed good as long as we hold the buffer pin.
*/
LockBuffer(buffer, BUFFER_LOCK_SHARE);
dp = (Page) BufferGetPage(buffer);
lines = PageGetMaxOffsetNumber(dp);
ntup = 0;
for (lineoff = FirstOffsetNumber, lpp = PageGetItemId(dp, lineoff);
lineoff <= lines;
lineoff++, lpp++)
{
if (ItemIdIsUsed(lpp))
{
HeapTupleData loctup;
bool valid;
loctup.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
loctup.t_len = ItemIdGetLength(lpp);
ItemPointerSet(&(loctup.t_self), page, lineoff);
valid = HeapTupleSatisfiesVisibility(&loctup, snapshot, buffer);
if (valid)
scan->rs_vistuples[ntup++] = lineoff;
}
}
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
Assert(ntup <= MaxHeapTuplesPerPage);
scan->rs_ntuples = ntup;
}
/* ----------------
* heapgettup - fetch next heap tuple
*
* Initialize the scan if not already done; then advance to the next
* tuple as indicated by "dir"; return the next tuple in scan->rs_ctup,
* or set scan->rs_ctup.t_data = NULL if no more tuples.
*
* dir == NoMovementScanDirection means "re-fetch the tuple indicated
* by scan->rs_ctup".
*
* Note: the reason nkeys/key are passed separately, even though they are
* kept in the scan descriptor, is that the caller may not want us to check
* the scankeys.
*
* Note: when we fall off the end of the scan in either direction, we
* reset rs_inited. This means that a further request with the same
* scan direction will restart the scan, which is a bit odd, but a
* request with the opposite scan direction will start a fresh scan
* in the proper direction. The latter is required behavior for cursors,
* while the former case is generally undefined behavior in Postgres
* so we don't care too much.
* ----------------
*/
static void
heapgettup(HeapScanDesc scan,
ScanDirection dir,
int nkeys,
ScanKey key)
{
HeapTuple tuple = &(scan->rs_ctup);
Snapshot snapshot = scan->rs_snapshot;
bool backward = ScanDirectionIsBackward(dir);
BlockNumber page;
Page dp;
int lines;
OffsetNumber lineoff;
int linesleft;
ItemId lpp;
/*
* calculate next starting lineoff, given scan direction
*/
if (ScanDirectionIsForward(dir))
{
if (!scan->rs_inited)
{
/*
* return null immediately if relation is empty
*/
if (scan->rs_nblocks == 0)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = 0; /* first page */
heapgetpage(scan, page);
lineoff = FirstOffsetNumber; /* first offnum */
scan->rs_inited = true;
}
else
{
/* continue from previously returned page/tuple */
page = scan->rs_cblock; /* current page */
lineoff = /* next offnum */
OffsetNumberNext(ItemPointerGetOffsetNumber(&(tuple->t_self)));
}
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = PageGetMaxOffsetNumber(dp);
/* page and lineoff now reference the physically next tid */
linesleft = lines - lineoff + 1;
}
else if (backward)
{
if (!scan->rs_inited)
{
/*
* return null immediately if relation is empty
*/
if (scan->rs_nblocks == 0)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = scan->rs_nblocks - 1; /* final page */
heapgetpage(scan, page);
}
else
{
/* continue from previously returned page/tuple */
page = scan->rs_cblock; /* current page */
}
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = PageGetMaxOffsetNumber(dp);
if (!scan->rs_inited)
{
lineoff = lines; /* final offnum */
scan->rs_inited = true;
}
else
{
lineoff = /* previous offnum */
OffsetNumberPrev(ItemPointerGetOffsetNumber(&(tuple->t_self)));
}
/* page and lineoff now reference the physically previous tid */
linesleft = lineoff;
}
else
{
/*
* ``no movement'' scan direction: refetch prior tuple
*/
if (!scan->rs_inited)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = ItemPointerGetBlockNumber(&(tuple->t_self));
if (page != scan->rs_cblock)
heapgetpage(scan, page);
/* Since the tuple was previously fetched, needn't lock page here */
dp = (Page) BufferGetPage(scan->rs_cbuf);
lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
lpp = PageGetItemId(dp, lineoff);
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
tuple->t_len = ItemIdGetLength(lpp);
return;
}
/*
* advance the scan until we find a qualifying tuple or run out of stuff
* to scan
*/
lpp = PageGetItemId(dp, lineoff);
for (;;)
{
while (linesleft > 0)
{
if (ItemIdIsUsed(lpp))
{
bool valid;
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
tuple->t_len = ItemIdGetLength(lpp);
ItemPointerSet(&(tuple->t_self), page, lineoff);
/*
* if current tuple qualifies, return it.
*/
valid = HeapTupleSatisfiesVisibility(tuple,
snapshot,
scan->rs_cbuf);
if (valid && key != NULL)
HeapKeyTest(tuple, RelationGetDescr(scan->rs_rd),
nkeys, key, valid);
if (valid)
{
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
return;
}
}
/*
* otherwise move to the next item on the page
*/
--linesleft;
if (backward)
{
--lpp; /* move back in this page's ItemId array */
--lineoff;
}
else
{
++lpp; /* move forward in this page's ItemId array */
++lineoff;
}
}
/*
* if we get here, it means we've exhausted the items on this page and
* it's time to move to the next.
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
/*
* return NULL if we've exhausted all the pages
*/
if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
{
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
scan->rs_cbuf = InvalidBuffer;
scan->rs_cblock = InvalidBlockNumber;
tuple->t_data = NULL;
scan->rs_inited = false;
return;
}
page = backward ? (page - 1) : (page + 1);
heapgetpage(scan, page);
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = PageGetMaxOffsetNumber((Page) dp);
linesleft = lines;
if (backward)
{
lineoff = lines;
lpp = PageGetItemId(dp, lines);
}
else
{
lineoff = FirstOffsetNumber;
lpp = PageGetItemId(dp, FirstOffsetNumber);
}
}
}
/* ----------------
* heapgettup_pagemode - fetch next heap tuple in page-at-a-time mode
*
* Same API as heapgettup, but used in page-at-a-time mode
*
* The internal logic is much the same as heapgettup's too, but there are some
* differences: we do not take the buffer content lock (that only needs to
* happen inside heapgetpage), and we iterate through just the tuples listed
* in rs_vistuples[] rather than all tuples on the page. Notice that
* lineindex is 0-based, where the corresponding loop variable lineoff in
* heapgettup is 1-based.
* ----------------
*/
static void
heapgettup_pagemode(HeapScanDesc scan,
ScanDirection dir,
int nkeys,
ScanKey key)
{
HeapTuple tuple = &(scan->rs_ctup);
bool backward = ScanDirectionIsBackward(dir);
BlockNumber page;
Page dp;
int lines;
int lineindex;
OffsetNumber lineoff;
int linesleft;
ItemId lpp;
/*
* calculate next starting lineindex, given scan direction
*/
if (ScanDirectionIsForward(dir))
{
if (!scan->rs_inited)
{
/*
* return null immediately if relation is empty
*/
if (scan->rs_nblocks == 0)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = 0; /* first page */
heapgetpage(scan, page);
lineindex = 0;
scan->rs_inited = true;
}
else
{
/* continue from previously returned page/tuple */
page = scan->rs_cblock; /* current page */
lineindex = scan->rs_cindex + 1;
}
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = scan->rs_ntuples;
/* page and lineindex now reference the next visible tid */
linesleft = lines - lineindex;
}
else if (backward)
{
if (!scan->rs_inited)
{
/*
* return null immediately if relation is empty
*/
if (scan->rs_nblocks == 0)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = scan->rs_nblocks - 1; /* final page */
heapgetpage(scan, page);
}
else
{
/* continue from previously returned page/tuple */
page = scan->rs_cblock; /* current page */
}
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = scan->rs_ntuples;
if (!scan->rs_inited)
{
lineindex = lines - 1;
scan->rs_inited = true;
}
else
{
lineindex = scan->rs_cindex - 1;
}
/* page and lineindex now reference the previous visible tid */
linesleft = lineindex + 1;
}
else
{
/*
* ``no movement'' scan direction: refetch prior tuple
*/
if (!scan->rs_inited)
{
Assert(!BufferIsValid(scan->rs_cbuf));
tuple->t_data = NULL;
return;
}
page = ItemPointerGetBlockNumber(&(tuple->t_self));
if (page != scan->rs_cblock)
heapgetpage(scan, page);
/* Since the tuple was previously fetched, needn't lock page here */
dp = (Page) BufferGetPage(scan->rs_cbuf);
lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
lpp = PageGetItemId(dp, lineoff);
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
tuple->t_len = ItemIdGetLength(lpp);
/* check that rs_cindex is in sync */
Assert(scan->rs_cindex < scan->rs_ntuples);
Assert(lineoff == scan->rs_vistuples[scan->rs_cindex]);
return;
}
/*
* advance the scan until we find a qualifying tuple or run out of stuff
* to scan
*/
for (;;)
{
while (linesleft > 0)
{
lineoff = scan->rs_vistuples[lineindex];
lpp = PageGetItemId(dp, lineoff);
Assert(ItemIdIsUsed(lpp));
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
tuple->t_len = ItemIdGetLength(lpp);
ItemPointerSet(&(tuple->t_self), page, lineoff);
/*
* if current tuple qualifies, return it.
*/
if (key != NULL)
{
bool valid;
HeapKeyTest(tuple, RelationGetDescr(scan->rs_rd),
nkeys, key, valid);
if (valid)
{
scan->rs_cindex = lineindex;
return;
}
}
else
{
scan->rs_cindex = lineindex;
return;
}
/*
* otherwise move to the next item on the page
*/
--linesleft;
if (backward)
--lineindex;
else
++lineindex;
}
/*
* if we get here, it means we've exhausted the items on this page and
* it's time to move to the next.
*/
/*
* return NULL if we've exhausted all the pages
*/
if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
{
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
scan->rs_cbuf = InvalidBuffer;
scan->rs_cblock = InvalidBlockNumber;
tuple->t_data = NULL;
scan->rs_inited = false;
return;
}
page = backward ? (page - 1) : (page + 1);
heapgetpage(scan, page);
dp = (Page) BufferGetPage(scan->rs_cbuf);
lines = scan->rs_ntuples;
linesleft = lines;
if (backward)
lineindex = lines - 1;
else
lineindex = 0;
}
}
#if defined(DISABLE_COMPLEX_MACRO)
/*
* This is formatted so oddly so that the correspondence to the macro
* definition in access/heapam.h is maintained.
*/
Datum
fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
bool *isnull)
{
return (
(attnum) > 0 ?
(
((isnull) ? (*(isnull) = false) : (dummyret) NULL),
HeapTupleNoNulls(tup) ?
(
(tupleDesc)->attrs[(attnum) - 1]->attcacheoff >= 0 ?
(
fetchatt((tupleDesc)->attrs[(attnum) - 1],
(char *) (tup)->t_data + (tup)->t_data->t_hoff +
(tupleDesc)->attrs[(attnum) - 1]->attcacheoff)
)
:
nocachegetattr((tup), (attnum), (tupleDesc), (isnull))
)
:
(
att_isnull((attnum) - 1, (tup)->t_data->t_bits) ?
(
((isnull) ? (*(isnull) = true) : (dummyret) NULL),
(Datum) NULL
)
:
(
nocachegetattr((tup), (attnum), (tupleDesc), (isnull))
)
)
)
:
(
(Datum) NULL
)
);
}
#endif /* defined(DISABLE_COMPLEX_MACRO) */
/* ----------------------------------------------------------------
* heap access method interface
* ----------------------------------------------------------------
*/
/* ----------------
* relation_open - open any relation by relation OID
*
* If lockmode is not "NoLock", the specified kind of lock is
* obtained on the relation. (Generally, NoLock should only be
* used if the caller knows it has some appropriate lock on the
* relation already.)
*
* An error is raised if the relation does not exist.
*
* NB: a "relation" is anything with a pg_class entry. The caller is
* expected to check whether the relkind is something it can handle.
* ----------------
*/
Relation
relation_open(Oid relationId, LOCKMODE lockmode)
{
Relation r;
Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
/* Get the lock before trying to open the relcache entry */
if (lockmode != NoLock)
LockRelationOid(relationId, lockmode);
/* The relcache does all the real work... */
r = RelationIdGetRelation(relationId);
if (!RelationIsValid(r))
elog(ERROR, "could not open relation with OID %u", relationId);
return r;
}
/* ----------------
* try_relation_open - open any relation by relation OID
*
* Same as relation_open, except return NULL instead of failing
* if the relation does not exist.
* ----------------
*/
Relation
try_relation_open(Oid relationId, LOCKMODE lockmode)
{
Relation r;
Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
/* Get the lock first */
if (lockmode != NoLock)
LockRelationOid(relationId, lockmode);
/*
* Now that we have the lock, probe to see if the relation really exists
* or not.
*/
if (!SearchSysCacheExists(RELOID,
ObjectIdGetDatum(relationId),
0, 0, 0))
{
/* Release useless lock */
if (lockmode != NoLock)
UnlockRelationOid(relationId, lockmode);
return NULL;
}
/* Should be safe to do a relcache load */
r = RelationIdGetRelation(relationId);
if (!RelationIsValid(r))
elog(ERROR, "could not open relation with OID %u", relationId);
return r;
}
/* ----------------
* relation_open_nowait - open but don't wait for lock
*
* Same as relation_open, except throw an error instead of waiting
* when the requested lock is not immediately obtainable.
* ----------------
*/
Relation
relation_open_nowait(Oid relationId, LOCKMODE lockmode)
{
Relation r;
Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
/* Get the lock before trying to open the relcache entry */
if (lockmode != NoLock)
{
if (!ConditionalLockRelationOid(relationId, lockmode))
{
/* try to throw error by name; relation could be deleted... */
char *relname = get_rel_name(relationId);
if (relname)
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on relation \"%s\"",
relname)));
else
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on relation with OID %u",
relationId)));
}
}
/* The relcache does all the real work... */
r = RelationIdGetRelation(relationId);
if (!RelationIsValid(r))
elog(ERROR, "could not open relation with OID %u", relationId);
return r;
}
/* ----------------
* relation_openrv - open any relation specified by a RangeVar
*
* Same as relation_open, but the relation is specified by a RangeVar.
* ----------------
*/
Relation
relation_openrv(const RangeVar *relation, LOCKMODE lockmode)
{
Oid relOid;
/*
* Check for shared-cache-inval messages before trying to open the
* relation. This is needed to cover the case where the name identifies a
* rel that has been dropped and recreated since the start of our
* transaction: if we don't flush the old syscache entry then we'll latch
* onto that entry and suffer an error when we do RelationIdGetRelation.
* Note that relation_open does not need to do this, since a relation's
* OID never changes.
*
* We skip this if asked for NoLock, on the assumption that the caller has
* already ensured some appropriate lock is held.
*/
if (lockmode != NoLock)
AcceptInvalidationMessages();
/* Look up the appropriate relation using namespace search */
relOid = RangeVarGetRelid(relation, false);
/* Let relation_open do the rest */
return relation_open(relOid, lockmode);
}
/* ----------------
* relation_close - close any relation
*
* If lockmode is not "NoLock", we then release the specified lock.
*
* Note that it is often sensible to hold a lock beyond relation_close;
* in that case, the lock is released automatically at xact end.
* ----------------
*/
void
relation_close(Relation relation, LOCKMODE lockmode)
{
LockRelId relid = relation->rd_lockInfo.lockRelId;
Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
/* The relcache does the real work... */
RelationClose(relation);
if (lockmode != NoLock)
UnlockRelationId(&relid, lockmode);
}
/* ----------------
* heap_open - open a heap relation by relation OID
*
* This is essentially relation_open plus check that the relation
* is not an index nor a composite type. (The caller should also
* check that it's not a view before assuming it has storage.)
* ----------------
*/
Relation
heap_open(Oid relationId, LOCKMODE lockmode)
{
Relation r;
r = relation_open(relationId, lockmode);
if (r->rd_rel->relkind == RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is an index",
RelationGetRelationName(r))));
else if (r->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a composite type",
RelationGetRelationName(r))));
pgstat_initstats(&r->pgstat_info, r);
return r;
}
/* ----------------
* heap_openrv - open a heap relation specified
* by a RangeVar node
*
* As above, but relation is specified by a RangeVar.
* ----------------
*/
Relation
heap_openrv(const RangeVar *relation, LOCKMODE lockmode)
{
Relation r;
r = relation_openrv(relation, lockmode);
if (r->rd_rel->relkind == RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is an index",
RelationGetRelationName(r))));
else if (r->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a composite type",
RelationGetRelationName(r))));
pgstat_initstats(&r->pgstat_info, r);
return r;
}
/* ----------------
* heap_beginscan - begin relation scan
* ----------------
*/
HeapScanDesc
heap_beginscan(Relation relation, Snapshot snapshot,
int nkeys, ScanKey key)
{
HeapScanDesc scan;
/*
* increment relation ref count while scanning relation
*
* This is just to make really sure the relcache entry won't go away while
* the scan has a pointer to it. Caller should be holding the rel open
* anyway, so this is redundant in all normal scenarios...
*/
RelationIncrementReferenceCount(relation);
/*
* allocate and initialize scan descriptor
*/
scan = (HeapScanDesc) palloc(sizeof(HeapScanDescData));
scan->rs_rd = relation;
scan->rs_snapshot = snapshot;
scan->rs_nkeys = nkeys;
/*
* we can use page-at-a-time mode if it's an MVCC-safe snapshot
*/
scan->rs_pageatatime = IsMVCCSnapshot(snapshot);
/* we only need to set this up once */
scan->rs_ctup.t_tableOid = RelationGetRelid(relation);
/*
* we do this here instead of in initscan() because heap_rescan also calls
* initscan() and we don't want to allocate memory again
*/
if (nkeys > 0)
scan->rs_key = (ScanKey) palloc(sizeof(ScanKeyData) * nkeys);
else
scan->rs_key = NULL;
pgstat_initstats(&scan->rs_pgstat_info, relation);
initscan(scan, key);
return scan;
}
/* ----------------
* heap_rescan - restart a relation scan
* ----------------
*/
void
heap_rescan(HeapScanDesc scan,
ScanKey key)
{
/*
* unpin scan buffers
*/
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
/*
* reinitialize scan descriptor
*/
initscan(scan, key);
}
/* ----------------
* heap_endscan - end relation scan
*
* See how to integrate with index scans.
* Check handling if reldesc caching.
* ----------------
*/
void
heap_endscan(HeapScanDesc scan)
{
/* Note: no locking manipulations needed */
/*
* unpin scan buffers
*/
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
/*
* decrement relation reference count and free scan descriptor storage
*/
RelationDecrementReferenceCount(scan->rs_rd);
if (scan->rs_key)
pfree(scan->rs_key);
pfree(scan);
}
/* ----------------
* heap_getnext - retrieve next tuple in scan
*
* Fix to work with index relations.
* We don't return the buffer anymore, but you can get it from the
* returned HeapTuple.
* ----------------
*/
#ifdef HEAPDEBUGALL
#define HEAPDEBUG_1 \
elog(DEBUG2, "heap_getnext([%s,nkeys=%d],dir=%d) called", \
RelationGetRelationName(scan->rs_rd), scan->rs_nkeys, (int) direction)
#define HEAPDEBUG_2 \
elog(DEBUG2, "heap_getnext returning EOS")
#define HEAPDEBUG_3 \
elog(DEBUG2, "heap_getnext returning tuple")
#else
#define HEAPDEBUG_1
#define HEAPDEBUG_2
#define HEAPDEBUG_3
#endif /* !defined(HEAPDEBUGALL) */
HeapTuple
heap_getnext(HeapScanDesc scan, ScanDirection direction)
{
/* Note: no locking manipulations needed */
HEAPDEBUG_1; /* heap_getnext( info ) */
if (scan->rs_pageatatime)
heapgettup_pagemode(scan, direction,
scan->rs_nkeys, scan->rs_key);
else
heapgettup(scan, direction, scan->rs_nkeys, scan->rs_key);
if (scan->rs_ctup.t_data == NULL)
{
HEAPDEBUG_2; /* heap_getnext returning EOS */
return NULL;
}
/*
* if we get here it means we have a new current scan tuple, so point to
* the proper return buffer and return the tuple.
*/
HEAPDEBUG_3; /* heap_getnext returning tuple */
pgstat_count_heap_getnext(&scan->rs_pgstat_info);
return &(scan->rs_ctup);
}
/*
* heap_fetch - retrieve tuple with given tid
*
* On entry, tuple->t_self is the TID to fetch. We pin the buffer holding
* the tuple, fill in the remaining fields of *tuple, and check the tuple
* against the specified snapshot.
*
* If successful (tuple found and passes snapshot time qual), then *userbuf
* is set to the buffer holding the tuple and TRUE is returned. The caller
* must unpin the buffer when done with the tuple.
*
* If the tuple is not found (ie, item number references a deleted slot),
* then tuple->t_data is set to NULL and FALSE is returned.
*
* If the tuple is found but fails the time qual check, then FALSE is returned
* but tuple->t_data is left pointing to the tuple.
*
* keep_buf determines what is done with the buffer in the FALSE-result cases.
* When the caller specifies keep_buf = true, we retain the pin on the buffer
* and return it in *userbuf (so the caller must eventually unpin it); when
* keep_buf = false, the pin is released and *userbuf is set to InvalidBuffer.
*
* It is somewhat inconsistent that we ereport() on invalid block number but
* return false on invalid item number. There are a couple of reasons though.
* One is that the caller can relatively easily check the block number for
* validity, but cannot check the item number without reading the page
* himself. Another is that when we are following a t_ctid link, we can be
* reasonably confident that the page number is valid (since VACUUM shouldn't
* truncate off the destination page without having killed the referencing
* tuple first), but the item number might well not be good.
*/
bool
heap_fetch(Relation relation,
Snapshot snapshot,
HeapTuple tuple,
Buffer *userbuf,
bool keep_buf,
PgStat_Info *pgstat_info)
{
/* Assume *userbuf is undefined on entry */
*userbuf = InvalidBuffer;
return heap_release_fetch(relation, snapshot, tuple,
userbuf, keep_buf, pgstat_info);
}
/*
* heap_release_fetch - retrieve tuple with given tid
*
* This has the same API as heap_fetch except that if *userbuf is not
* InvalidBuffer on entry, that buffer will be released before reading
* the new page. This saves a separate ReleaseBuffer step and hence
* one entry into the bufmgr when looping through multiple fetches.
* Also, if *userbuf is the same buffer that holds the target tuple,
* we avoid bufmgr manipulation altogether.
*/
bool
heap_release_fetch(Relation relation,
Snapshot snapshot,
HeapTuple tuple,
Buffer *userbuf,
bool keep_buf,
PgStat_Info *pgstat_info)
{
ItemPointer tid = &(tuple->t_self);
ItemId lp;
Buffer buffer;
PageHeader dp;
OffsetNumber offnum;
bool valid;
/*
* get the buffer from the relation descriptor. Note that this does a
* buffer pin, and releases the old *userbuf if not InvalidBuffer.
*/
buffer = ReleaseAndReadBuffer(*userbuf, relation,
ItemPointerGetBlockNumber(tid));
/*
* Need share lock on buffer to examine tuple commit status.
*/
LockBuffer(buffer, BUFFER_LOCK_SHARE);
dp = (PageHeader) BufferGetPage(buffer);
/*
* We'd better check for out-of-range offnum in case of VACUUM since the
* TID was obtained.
*/
offnum = ItemPointerGetOffsetNumber(tid);
if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(dp))
{
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
if (keep_buf)
*userbuf = buffer;
else
{
ReleaseBuffer(buffer);
*userbuf = InvalidBuffer;
}
tuple->t_data = NULL;
return false;
}
/*
* get the item line pointer corresponding to the requested tid
*/
lp = PageGetItemId(dp, offnum);
/*
* Must check for deleted tuple.
*/
if (!ItemIdIsUsed(lp))
{
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
if (keep_buf)
*userbuf = buffer;
else
{
ReleaseBuffer(buffer);
*userbuf = InvalidBuffer;
}
tuple->t_data = NULL;
return false;
}
/*
* fill in *tuple fields
*/
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
tuple->t_len = ItemIdGetLength(lp);
tuple->t_tableOid = RelationGetRelid(relation);
/*
* check time qualification of tuple, then release lock
*/
valid = HeapTupleSatisfiesVisibility(tuple, snapshot, buffer);
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
if (valid)
{
/*
* All checks passed, so return the tuple as valid. Caller is now
* responsible for releasing the buffer.
*/
*userbuf = buffer;
/* Count the successful fetch in *pgstat_info, if given. */
if (pgstat_info != NULL)
pgstat_count_heap_fetch(pgstat_info);
return true;
}
/* Tuple failed time qual, but maybe caller wants to see it anyway. */
if (keep_buf)
*userbuf = buffer;
else
{
ReleaseBuffer(buffer);
*userbuf = InvalidBuffer;
}
return false;
}
/*
* heap_get_latest_tid - get the latest tid of a specified tuple
*
* Actually, this gets the latest version that is visible according to
* the passed snapshot. You can pass SnapshotDirty to get the very latest,
* possibly uncommitted version.
*
* *tid is both an input and an output parameter: it is updated to
* show the latest version of the row. Note that it will not be changed
* if no version of the row passes the snapshot test.
*/
void
heap_get_latest_tid(Relation relation,
Snapshot snapshot,
ItemPointer tid)
{
BlockNumber blk;
ItemPointerData ctid;
TransactionId priorXmax;
/* this is to avoid Assert failures on bad input */
if (!ItemPointerIsValid(tid))
return;
/*
* Since this can be called with user-supplied TID, don't trust the input
* too much. (RelationGetNumberOfBlocks is an expensive check, so we
* don't check t_ctid links again this way. Note that it would not do to
* call it just once and save the result, either.)
*/
blk = ItemPointerGetBlockNumber(tid);
if (blk >= RelationGetNumberOfBlocks(relation))
elog(ERROR, "block number %u is out of range for relation \"%s\"",
blk, RelationGetRelationName(relation));
/*
* Loop to chase down t_ctid links. At top of loop, ctid is the tuple we
* need to examine, and *tid is the TID we will return if ctid turns out
* to be bogus.
*
* Note that we will loop until we reach the end of the t_ctid chain.
* Depending on the snapshot passed, there might be at most one visible
* version of the row, but we don't try to optimize for that.
*/
ctid = *tid;
priorXmax = InvalidTransactionId; /* cannot check first XMIN */
for (;;)
{
Buffer buffer;
PageHeader dp;
OffsetNumber offnum;
ItemId lp;
HeapTupleData tp;
bool valid;
/*
* Read, pin, and lock the page.
*/
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&ctid));
LockBuffer(buffer, BUFFER_LOCK_SHARE);
dp = (PageHeader) BufferGetPage(buffer);
/*
* Check for bogus item number. This is not treated as an error
* condition because it can happen while following a t_ctid link. We
* just assume that the prior tid is OK and return it unchanged.
*/
offnum = ItemPointerGetOffsetNumber(&ctid);
if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(dp))
{
UnlockReleaseBuffer(buffer);
break;
}
lp = PageGetItemId(dp, offnum);
if (!ItemIdIsUsed(lp))
{
UnlockReleaseBuffer(buffer);
break;
}
/* OK to access the tuple */
tp.t_self = ctid;
tp.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
tp.t_len = ItemIdGetLength(lp);
/*
* After following a t_ctid link, we might arrive at an unrelated
* tuple. Check for XMIN match.
*/
if (TransactionIdIsValid(priorXmax) &&
!TransactionIdEquals(priorXmax, HeapTupleHeaderGetXmin(tp.t_data)))
{
UnlockReleaseBuffer(buffer);
break;
}
/*
* Check time qualification of tuple; if visible, set it as the new
* result candidate.
*/
valid = HeapTupleSatisfiesVisibility(&tp, snapshot, buffer);
if (valid)
*tid = ctid;
/*
* If there's a valid t_ctid link, follow it, else we're done.
*/
if ((tp.t_data->t_infomask & (HEAP_XMAX_INVALID | HEAP_IS_LOCKED)) ||
ItemPointerEquals(&tp.t_self, &tp.t_data->t_ctid))
{
UnlockReleaseBuffer(buffer);
break;
}
ctid = tp.t_data->t_ctid;
priorXmax = HeapTupleHeaderGetXmax(tp.t_data);
UnlockReleaseBuffer(buffer);
} /* end of loop */
}
/*
* heap_insert - insert tuple into a heap
*
* The new tuple is stamped with current transaction ID and the specified
* command ID.
*
* If use_wal is false, the new tuple is not logged in WAL, even for a
* non-temp relation. Safe usage of this behavior requires that we arrange
* that all new tuples go into new pages not containing any tuples from other
* transactions, that the relation gets fsync'd before commit, and that the
* transaction emits at least one WAL record to ensure RecordTransactionCommit
* will decide to WAL-log the commit. (See also heap_sync() comments)
*
* use_fsm is passed directly to RelationGetBufferForTuple, which see for
* more info.
*
* Note that use_wal and use_fsm will be applied when inserting into the
* heap's TOAST table, too, if the tuple requires any out-of-line data.
*
* The return value is the OID assigned to the tuple (either here or by the
* caller), or InvalidOid if no OID. The header fields of *tup are updated
* to match the stored tuple; in particular tup->t_self receives the actual
* TID where the tuple was stored. But note that any toasting of fields
* within the tuple data is NOT reflected into *tup.
*/
Oid
heap_insert(Relation relation, HeapTuple tup, CommandId cid,
bool use_wal, bool use_fsm)
{
TransactionId xid = GetCurrentTransactionId();
HeapTuple heaptup;
Buffer buffer;
if (relation->rd_rel->relhasoids)
{
#ifdef NOT_USED
/* this is redundant with an Assert in HeapTupleSetOid */
Assert(tup->t_data->t_infomask & HEAP_HASOID);
#endif
/*
* If the object id of this tuple has already been assigned, trust the
* caller. There are a couple of ways this can happen. At initial db
* creation, the backend program sets oids for tuples. When we define
* an index, we set the oid. Finally, in the future, we may allow
* users to set their own object ids in order to support a persistent
* object store (objects need to contain pointers to one another).
*/
if (!OidIsValid(HeapTupleGetOid(tup)))
HeapTupleSetOid(tup, GetNewOid(relation));
}
else
{
/* check there is not space for an OID */
Assert(!(tup->t_data->t_infomask & HEAP_HASOID));
}
tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
tup->t_data->t_infomask |= HEAP_XMAX_INVALID;
HeapTupleHeaderSetXmin(tup->t_data, xid);
HeapTupleHeaderSetCmin(tup->t_data, cid);
HeapTupleHeaderSetXmax(tup->t_data, 0); /* for cleanliness */
tup->t_tableOid = RelationGetRelid(relation);
/*
* If the new tuple is too big for storage or contains already toasted
* out-of-line attributes from some other relation, invoke the toaster.
*
* Note: below this point, heaptup is the data we actually intend to store
* into the relation; tup is the caller's original untoasted data.
*/
if (relation->rd_rel->relkind == RELKIND_TOASTVALUE)
{
/* toast table entries should never be recursively toasted */
Assert(!HeapTupleHasExternal(tup));
heaptup = tup;
}
else if (HeapTupleHasExternal(tup) || tup->t_len > TOAST_TUPLE_THRESHOLD)
heaptup = toast_insert_or_update(relation, tup, NULL,
use_wal, use_fsm);
else
heaptup = tup;
/* Find buffer to insert this tuple into */
buffer = RelationGetBufferForTuple(relation, heaptup->t_len,
InvalidBuffer, use_fsm);
/* NO EREPORT(ERROR) from here till changes are logged */
START_CRIT_SECTION();
RelationPutHeapTuple(relation, buffer, heaptup);
MarkBufferDirty(buffer);
/* XLOG stuff */
if (relation->rd_istemp)
{
/* No XLOG record, but still need to flag that XID exists on disk */
MyXactMadeTempRelUpdate = true;
}
else if (use_wal)
{
xl_heap_insert xlrec;
xl_heap_header xlhdr;
XLogRecPtr recptr;
XLogRecData rdata[3];
Page page = BufferGetPage(buffer);
uint8 info = XLOG_HEAP_INSERT;
xlrec.target.node = relation->rd_node;
xlrec.target.tid = heaptup->t_self;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapInsert;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
xlhdr.t_infomask2 = heaptup->t_data->t_infomask2;
xlhdr.t_infomask = heaptup->t_data->t_infomask;
xlhdr.t_hoff = heaptup->t_data->t_hoff;
/*
* note we mark rdata[1] as belonging to buffer; if XLogInsert decides
* to write the whole page to the xlog, we don't need to store
* xl_heap_header in the xlog.
*/
rdata[1].data = (char *) &xlhdr;
rdata[1].len = SizeOfHeapHeader;
rdata[1].buffer = buffer;
rdata[1].buffer_std = true;
rdata[1].next = &(rdata[2]);
/* PG73FORMAT: write bitmap [+ padding] [+ oid] + data */
rdata[2].data = (char *) heaptup->t_data + offsetof(HeapTupleHeaderData, t_bits);
rdata[2].len = heaptup->t_len - offsetof(HeapTupleHeaderData, t_bits);
rdata[2].buffer = buffer;
rdata[2].buffer_std = true;
rdata[2].next = NULL;
/*
* If this is the single and first tuple on page, we can reinit the
* page instead of restoring the whole thing. Set flag, and hide
* buffer references from XLogInsert.
*/
if (ItemPointerGetOffsetNumber(&(heaptup->t_self)) == FirstOffsetNumber &&
PageGetMaxOffsetNumber(page) == FirstOffsetNumber)
{
info |= XLOG_HEAP_INIT_PAGE;
rdata[1].buffer = rdata[2].buffer = InvalidBuffer;
}
recptr = XLogInsert(RM_HEAP_ID, info, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buffer);
/*
* If tuple is cachable, mark it for invalidation from the caches in case
* we abort. Note it is OK to do this after releasing the buffer, because
* the heaptup data structure is all in local memory, not in the shared
* buffer.
*/
CacheInvalidateHeapTuple(relation, heaptup);
pgstat_count_heap_insert(&relation->pgstat_info);
/*
* If heaptup is a private copy, release it. Don't forget to copy t_self
* back to the caller's image, too.
*/
if (heaptup != tup)
{
tup->t_self = heaptup->t_self;
heap_freetuple(heaptup);
}
return HeapTupleGetOid(tup);
}
/*
* simple_heap_insert - insert a tuple
*
* Currently, this routine differs from heap_insert only in supplying
* a default command ID and not allowing access to the speedup options.
*
* This should be used rather than using heap_insert directly in most places
* where we are modifying system catalogs.
*/
Oid
simple_heap_insert(Relation relation, HeapTuple tup)
{
return heap_insert(relation, tup, GetCurrentCommandId(), true, true);
}
/*
* heap_delete - delete a tuple
*
* NB: do not call this directly unless you are prepared to deal with
* concurrent-update conditions. Use simple_heap_delete instead.
*
* relation - table to be modified (caller must hold suitable lock)
* tid - TID of tuple to be deleted
* ctid - output parameter, used only for failure case (see below)
* update_xmax - output parameter, used only for failure case (see below)
* cid - delete command ID (used for visibility test, and stored into
* cmax if successful)
* crosscheck - if not InvalidSnapshot, also check tuple against this
* wait - true if should wait for any conflicting update to commit/abort
*
* Normal, successful return value is HeapTupleMayBeUpdated, which
* actually means we did delete it. Failure return codes are
* HeapTupleSelfUpdated, HeapTupleUpdated, or HeapTupleBeingUpdated
* (the last only possible if wait == false).
*
* In the failure cases, the routine returns the tuple's t_ctid and t_xmax.
* If t_ctid is the same as tid, the tuple was deleted; if different, the
* tuple was updated, and t_ctid is the location of the replacement tuple.
* (t_xmax is needed to verify that the replacement tuple matches.)
*/
HTSU_Result
heap_delete(Relation relation, ItemPointer tid,
ItemPointer ctid, TransactionId *update_xmax,
CommandId cid, Snapshot crosscheck, bool wait)
{
HTSU_Result result;
TransactionId xid = GetCurrentTransactionId();
ItemId lp;
HeapTupleData tp;
PageHeader dp;
Buffer buffer;
bool have_tuple_lock = false;
bool iscombo;
Assert(ItemPointerIsValid(tid));
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
dp = (PageHeader) BufferGetPage(buffer);
lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
tp.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
tp.t_len = ItemIdGetLength(lp);
tp.t_self = *tid;
l1:
result = HeapTupleSatisfiesUpdate(tp.t_data, cid, buffer);
if (result == HeapTupleInvisible)
{
UnlockReleaseBuffer(buffer);
elog(ERROR, "attempted to delete invisible tuple");
}
else if (result == HeapTupleBeingUpdated && wait)
{
TransactionId xwait;
uint16 infomask;
/* must copy state data before unlocking buffer */
xwait = HeapTupleHeaderGetXmax(tp.t_data);
infomask = tp.t_data->t_infomask;
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* Acquire tuple lock to establish our priority for the tuple (see
* heap_lock_tuple). LockTuple will release us when we are
* next-in-line for the tuple.
*
* If we are forced to "start over" below, we keep the tuple lock;
* this arranges that we stay at the head of the line while rechecking
* tuple state.
*/
if (!have_tuple_lock)
{
LockTuple(relation, &(tp.t_self), ExclusiveLock);
have_tuple_lock = true;
}
/*
* Sleep until concurrent transaction ends. Note that we don't care
* if the locker has an exclusive or shared lock, because we need
* exclusive.
*/
if (infomask & HEAP_XMAX_IS_MULTI)
{
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* If xwait had just locked the tuple then some other xact could
* update this tuple before we get to this point. Check for xmax
* change, and start over if so.
*/
if (!(tp.t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(tp.t_data),
xwait))
goto l1;
/*
* You might think the multixact is necessarily done here, but not
* so: it could have surviving members, namely our own xact or
* other subxacts of this backend. It is legal for us to delete
* the tuple in either case, however (the latter case is
* essentially a situation of upgrading our former shared lock to
* exclusive). We don't bother changing the on-disk hint bits
* since we are about to overwrite the xmax altogether.
*/
}
else
{
/* wait for regular transaction to end */
XactLockTableWait(xwait);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* xwait is done, but if xwait had just locked the tuple then some
* other xact could update this tuple before we get to this point.
* Check for xmax change, and start over if so.
*/
if ((tp.t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(tp.t_data),
xwait))
goto l1;
/* Otherwise we can mark it committed or aborted */
if (!(tp.t_data->t_infomask & (HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID)))
{
if (TransactionIdDidCommit(xwait))
tp.t_data->t_infomask |= HEAP_XMAX_COMMITTED;
else
tp.t_data->t_infomask |= HEAP_XMAX_INVALID;
SetBufferCommitInfoNeedsSave(buffer);
}
}
/*
* We may overwrite if previous xmax aborted, or if it committed but
* only locked the tuple without updating it.
*/
if (tp.t_data->t_infomask & (HEAP_XMAX_INVALID |
HEAP_IS_LOCKED))
result = HeapTupleMayBeUpdated;
else
result = HeapTupleUpdated;
}
if (crosscheck != InvalidSnapshot && result == HeapTupleMayBeUpdated)
{
/* Perform additional check for serializable RI updates */
if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
result = HeapTupleUpdated;
}
if (result != HeapTupleMayBeUpdated)
{
Assert(result == HeapTupleSelfUpdated ||
result == HeapTupleUpdated ||
result == HeapTupleBeingUpdated);
Assert(!(tp.t_data->t_infomask & HEAP_XMAX_INVALID));
*ctid = tp.t_data->t_ctid;
*update_xmax = HeapTupleHeaderGetXmax(tp.t_data);
UnlockReleaseBuffer(buffer);
if (have_tuple_lock)
UnlockTuple(relation, &(tp.t_self), ExclusiveLock);
return result;
}
/* replace cid with a combo cid if necessary */
HeapTupleHeaderAdjustCmax(tp.t_data, &cid, &iscombo);
START_CRIT_SECTION();
/* store transaction information of xact deleting the tuple */
tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
HeapTupleHeaderSetXmax(tp.t_data, xid);
HeapTupleHeaderSetCmax(tp.t_data, cid, iscombo);
/* Make sure there is no forward chain link in t_ctid */
tp.t_data->t_ctid = tp.t_self;
MarkBufferDirty(buffer);
/* XLOG stuff */
if (!relation->rd_istemp)
{
xl_heap_delete xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
xlrec.target.node = relation->rd_node;
xlrec.target.tid = tp.t_self;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapDelete;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
rdata[1].data = NULL;
rdata[1].len = 0;
rdata[1].buffer = buffer;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_DELETE, rdata);
PageSetLSN(dp, recptr);
PageSetTLI(dp, ThisTimeLineID);
}
else
{
/* No XLOG record, but still need to flag that XID exists on disk */
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* If the tuple has toasted out-of-line attributes, we need to delete
* those items too. We have to do this before releasing the buffer
* because we need to look at the contents of the tuple, but it's OK to
* release the content lock on the buffer first.
*/
if (relation->rd_rel->relkind == RELKIND_TOASTVALUE)
{
/* toast table entries should never be recursively toasted */
Assert(!HeapTupleHasExternal(&tp));
}
else if (HeapTupleHasExternal(&tp))
toast_delete(relation, &tp);
/*
* Mark tuple for invalidation from system caches at next command
* boundary. We have to do this before releasing the buffer because we
* need to look at the contents of the tuple.
*/
CacheInvalidateHeapTuple(relation, &tp);
/* Now we can release the buffer */
ReleaseBuffer(buffer);
/*
* Release the lmgr tuple lock, if we had it.
*/
if (have_tuple_lock)
UnlockTuple(relation, &(tp.t_self), ExclusiveLock);
pgstat_count_heap_delete(&relation->pgstat_info);
return HeapTupleMayBeUpdated;
}
/*
* simple_heap_delete - delete a tuple
*
* This routine may be used to delete a tuple when concurrent updates of
* the target tuple are not expected (for example, because we have a lock
* on the relation associated with the tuple). Any failure is reported
* via ereport().
*/
void
simple_heap_delete(Relation relation, ItemPointer tid)
{
HTSU_Result result;
ItemPointerData update_ctid;
TransactionId update_xmax;
result = heap_delete(relation, tid,
&update_ctid, &update_xmax,
GetCurrentCommandId(), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{
case HeapTupleSelfUpdated:
/* Tuple was already updated in current command? */
elog(ERROR, "tuple already updated by self");
break;
case HeapTupleMayBeUpdated:
/* done successfully */
break;
case HeapTupleUpdated:
elog(ERROR, "tuple concurrently updated");
break;
default:
elog(ERROR, "unrecognized heap_delete status: %u", result);
break;
}
}
/*
* heap_update - replace a tuple
*
* NB: do not call this directly unless you are prepared to deal with
* concurrent-update conditions. Use simple_heap_update instead.
*
* relation - table to be modified (caller must hold suitable lock)
* otid - TID of old tuple to be replaced
* newtup - newly constructed tuple data to store
* ctid - output parameter, used only for failure case (see below)
* update_xmax - output parameter, used only for failure case (see below)
* cid - update command ID (used for visibility test, and stored into
* cmax/cmin if successful)
* crosscheck - if not InvalidSnapshot, also check old tuple against this
* wait - true if should wait for any conflicting update to commit/abort
*
* Normal, successful return value is HeapTupleMayBeUpdated, which
* actually means we *did* update it. Failure return codes are
* HeapTupleSelfUpdated, HeapTupleUpdated, or HeapTupleBeingUpdated
* (the last only possible if wait == false).
*
* On success, the header fields of *newtup are updated to match the new
* stored tuple; in particular, newtup->t_self is set to the TID where the
* new tuple was inserted. However, any TOAST changes in the new tuple's
* data are not reflected into *newtup.
*
* In the failure cases, the routine returns the tuple's t_ctid and t_xmax.
* If t_ctid is the same as otid, the tuple was deleted; if different, the
* tuple was updated, and t_ctid is the location of the replacement tuple.
* (t_xmax is needed to verify that the replacement tuple matches.)
*/
HTSU_Result
heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
ItemPointer ctid, TransactionId *update_xmax,
CommandId cid, Snapshot crosscheck, bool wait)
{
HTSU_Result result;
TransactionId xid = GetCurrentTransactionId();
ItemId lp;
HeapTupleData oldtup;
HeapTuple heaptup;
PageHeader dp;
Buffer buffer,
newbuf;
bool need_toast,
already_marked;
Size newtupsize,
pagefree;
bool have_tuple_lock = false;
bool iscombo;
Assert(ItemPointerIsValid(otid));
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(otid));
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
dp = (PageHeader) BufferGetPage(buffer);
lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(otid));
oldtup.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
oldtup.t_len = ItemIdGetLength(lp);
oldtup.t_self = *otid;
/*
* Note: beyond this point, use oldtup not otid to refer to old tuple.
* otid may very well point at newtup->t_self, which we will overwrite
* with the new tuple's location, so there's great risk of confusion if we
* use otid anymore.
*/
l2:
result = HeapTupleSatisfiesUpdate(oldtup.t_data, cid, buffer);
if (result == HeapTupleInvisible)
{
UnlockReleaseBuffer(buffer);
elog(ERROR, "attempted to update invisible tuple");
}
else if (result == HeapTupleBeingUpdated && wait)
{
TransactionId xwait;
uint16 infomask;
/* must copy state data before unlocking buffer */
xwait = HeapTupleHeaderGetXmax(oldtup.t_data);
infomask = oldtup.t_data->t_infomask;
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* Acquire tuple lock to establish our priority for the tuple (see
* heap_lock_tuple). LockTuple will release us when we are
* next-in-line for the tuple.
*
* If we are forced to "start over" below, we keep the tuple lock;
* this arranges that we stay at the head of the line while rechecking
* tuple state.
*/
if (!have_tuple_lock)
{
LockTuple(relation, &(oldtup.t_self), ExclusiveLock);
have_tuple_lock = true;
}
/*
* Sleep until concurrent transaction ends. Note that we don't care
* if the locker has an exclusive or shared lock, because we need
* exclusive.
*/
if (infomask & HEAP_XMAX_IS_MULTI)
{
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* If xwait had just locked the tuple then some other xact could
* update this tuple before we get to this point. Check for xmax
* change, and start over if so.
*/
if (!(oldtup.t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(oldtup.t_data),
xwait))
goto l2;
/*
* You might think the multixact is necessarily done here, but not
* so: it could have surviving members, namely our own xact or
* other subxacts of this backend. It is legal for us to update
* the tuple in either case, however (the latter case is
* essentially a situation of upgrading our former shared lock to
* exclusive). We don't bother changing the on-disk hint bits
* since we are about to overwrite the xmax altogether.
*/
}
else
{
/* wait for regular transaction to end */
XactLockTableWait(xwait);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* xwait is done, but if xwait had just locked the tuple then some
* other xact could update this tuple before we get to this point.
* Check for xmax change, and start over if so.
*/
if ((oldtup.t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(oldtup.t_data),
xwait))
goto l2;
/* Otherwise we can mark it committed or aborted */
if (!(oldtup.t_data->t_infomask & (HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID)))
{
if (TransactionIdDidCommit(xwait))
oldtup.t_data->t_infomask |= HEAP_XMAX_COMMITTED;
else
oldtup.t_data->t_infomask |= HEAP_XMAX_INVALID;
SetBufferCommitInfoNeedsSave(buffer);
}
}
/*
* We may overwrite if previous xmax aborted, or if it committed but
* only locked the tuple without updating it.
*/
if (oldtup.t_data->t_infomask & (HEAP_XMAX_INVALID |
HEAP_IS_LOCKED))
result = HeapTupleMayBeUpdated;
else
result = HeapTupleUpdated;
}
if (crosscheck != InvalidSnapshot && result == HeapTupleMayBeUpdated)
{
/* Perform additional check for serializable RI updates */
if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
result = HeapTupleUpdated;
}
if (result != HeapTupleMayBeUpdated)
{
Assert(result == HeapTupleSelfUpdated ||
result == HeapTupleUpdated ||
result == HeapTupleBeingUpdated);
Assert(!(oldtup.t_data->t_infomask & HEAP_XMAX_INVALID));
*ctid = oldtup.t_data->t_ctid;
*update_xmax = HeapTupleHeaderGetXmax(oldtup.t_data);
UnlockReleaseBuffer(buffer);
if (have_tuple_lock)
UnlockTuple(relation, &(oldtup.t_self), ExclusiveLock);
return result;
}
/* Fill in OID and transaction status data for newtup */
if (relation->rd_rel->relhasoids)
{
#ifdef NOT_USED
/* this is redundant with an Assert in HeapTupleSetOid */
Assert(newtup->t_data->t_infomask & HEAP_HASOID);
#endif
HeapTupleSetOid(newtup, HeapTupleGetOid(&oldtup));
}
else
{
/* check there is not space for an OID */
Assert(!(newtup->t_data->t_infomask & HEAP_HASOID));
}
newtup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
newtup->t_data->t_infomask |= (HEAP_XMAX_INVALID | HEAP_UPDATED);
HeapTupleHeaderSetXmin(newtup->t_data, xid);
HeapTupleHeaderSetCmin(newtup->t_data, cid);
HeapTupleHeaderSetXmax(newtup->t_data, 0); /* for cleanliness */
/*
* Replace cid with a combo cid if necessary. Note that we already put
* the plain cid into the new tuple.
*/
HeapTupleHeaderAdjustCmax(oldtup.t_data, &cid, &iscombo);
/*
* If the toaster needs to be activated, OR if the new tuple will not fit
* on the same page as the old, then we need to release the content lock
* (but not the pin!) on the old tuple's buffer while we are off doing
* TOAST and/or table-file-extension work. We must mark the old tuple to
* show that it's already being updated, else other processes may try to
* update it themselves.
*
* We need to invoke the toaster if there are already any out-of-line
* toasted values present, or if the new tuple is over-threshold.
*/
if (relation->rd_rel->relkind == RELKIND_TOASTVALUE)
{
/* toast table entries should never be recursively toasted */
Assert(!HeapTupleHasExternal(&oldtup));
Assert(!HeapTupleHasExternal(newtup));
need_toast = false;
}
else
need_toast = (HeapTupleHasExternal(&oldtup) ||
HeapTupleHasExternal(newtup) ||
newtup->t_len > TOAST_TUPLE_THRESHOLD);
pagefree = PageGetFreeSpace((Page) dp);
newtupsize = MAXALIGN(newtup->t_len);
if (need_toast || newtupsize > pagefree)
{
oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
HeapTupleHeaderSetXmax(oldtup.t_data, xid);
HeapTupleHeaderSetCmax(oldtup.t_data, cid, iscombo);
/* temporarily make it look not-updated */
oldtup.t_data->t_ctid = oldtup.t_self;
already_marked = true;
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* Let the toaster do its thing, if needed.
*
* Note: below this point, heaptup is the data we actually intend to
* store into the relation; newtup is the caller's original untoasted
* data.
*/
if (need_toast)
{
/* Note we always use WAL and FSM during updates */
heaptup = toast_insert_or_update(relation, newtup, &oldtup,
true, true);
newtupsize = MAXALIGN(heaptup->t_len);
}
else
heaptup = newtup;
/*
* Now, do we need a new page for the tuple, or not? This is a bit
* tricky since someone else could have added tuples to the page while
* we weren't looking. We have to recheck the available space after
* reacquiring the buffer lock. But don't bother to do that if the
* former amount of free space is still not enough; it's unlikely
* there's more free now than before.
*
* What's more, if we need to get a new page, we will need to acquire
* buffer locks on both old and new pages. To avoid deadlock against
* some other backend trying to get the same two locks in the other
* order, we must be consistent about the order we get the locks in.
* We use the rule "lock the lower-numbered page of the relation
* first". To implement this, we must do RelationGetBufferForTuple
* while not holding the lock on the old page, and we must rely on it
* to get the locks on both pages in the correct order.
*/
if (newtupsize > pagefree)
{
/* Assume there's no chance to put heaptup on same page. */
newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
buffer, true);
}
else
{
/* Re-acquire the lock on the old tuple's page. */
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/* Re-check using the up-to-date free space */
pagefree = PageGetFreeSpace((Page) dp);
if (newtupsize > pagefree)
{
/*
* Rats, it doesn't fit anymore. We must now unlock and
* relock to avoid deadlock. Fortunately, this path should
* seldom be taken.
*/
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
buffer, true);
}
else
{
/* OK, it fits here, so we're done. */
newbuf = buffer;
}
}
}
else
{
/* No TOAST work needed, and it'll fit on same page */
already_marked = false;
newbuf = buffer;
heaptup = newtup;
}
/*
* At this point newbuf and buffer are both pinned and locked, and newbuf
* has enough space for the new tuple. If they are the same buffer, only
* one pin is held.
*/
/* NO EREPORT(ERROR) from here till changes are logged */
START_CRIT_SECTION();
RelationPutHeapTuple(relation, newbuf, heaptup); /* insert new tuple */
if (!already_marked)
{
oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
HeapTupleHeaderSetXmax(oldtup.t_data, xid);
HeapTupleHeaderSetCmax(oldtup.t_data, cid, iscombo);
}
/* record address of new tuple in t_ctid of old one */
oldtup.t_data->t_ctid = heaptup->t_self;
if (newbuf != buffer)
MarkBufferDirty(newbuf);
MarkBufferDirty(buffer);
/* XLOG stuff */
if (!relation->rd_istemp)
{
XLogRecPtr recptr = log_heap_update(relation, buffer, oldtup.t_self,
newbuf, heaptup, false);
if (newbuf != buffer)
{
PageSetLSN(BufferGetPage(newbuf), recptr);
PageSetTLI(BufferGetPage(newbuf), ThisTimeLineID);
}
PageSetLSN(BufferGetPage(buffer), recptr);
PageSetTLI(BufferGetPage(buffer), ThisTimeLineID);
}
else
{
/* No XLOG record, but still need to flag that XID exists on disk */
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
if (newbuf != buffer)
LockBuffer(newbuf, BUFFER_LOCK_UNLOCK);
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/*
* Mark old tuple for invalidation from system caches at next command
* boundary. We have to do this before releasing the buffer because we
* need to look at the contents of the tuple.
*/
CacheInvalidateHeapTuple(relation, &oldtup);
/* Now we can release the buffer(s) */
if (newbuf != buffer)
ReleaseBuffer(newbuf);
ReleaseBuffer(buffer);
/*
* If new tuple is cachable, mark it for invalidation from the caches in
* case we abort. Note it is OK to do this after releasing the buffer,
* because the heaptup data structure is all in local memory, not in the
* shared buffer.
*/
CacheInvalidateHeapTuple(relation, heaptup);
/*
* Release the lmgr tuple lock, if we had it.
*/
if (have_tuple_lock)
UnlockTuple(relation, &(oldtup.t_self), ExclusiveLock);
pgstat_count_heap_update(&relation->pgstat_info);
/*
* If heaptup is a private copy, release it. Don't forget to copy t_self
* back to the caller's image, too.
*/
if (heaptup != newtup)
{
newtup->t_self = heaptup->t_self;
heap_freetuple(heaptup);
}
return HeapTupleMayBeUpdated;
}
/*
* simple_heap_update - replace a tuple
*
* This routine may be used to update a tuple when concurrent updates of
* the target tuple are not expected (for example, because we have a lock
* on the relation associated with the tuple). Any failure is reported
* via ereport().
*/
void
simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
{
HTSU_Result result;
ItemPointerData update_ctid;
TransactionId update_xmax;
result = heap_update(relation, otid, tup,
&update_ctid, &update_xmax,
GetCurrentCommandId(), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{
case HeapTupleSelfUpdated:
/* Tuple was already updated in current command? */
elog(ERROR, "tuple already updated by self");
break;
case HeapTupleMayBeUpdated:
/* done successfully */
break;
case HeapTupleUpdated:
elog(ERROR, "tuple concurrently updated");
break;
default:
elog(ERROR, "unrecognized heap_update status: %u", result);
break;
}
}
/*
* heap_lock_tuple - lock a tuple in shared or exclusive mode
*
* Note that this acquires a buffer pin, which the caller must release.
*
* Input parameters:
* relation: relation containing tuple (caller must hold suitable lock)
* tuple->t_self: TID of tuple to lock (rest of struct need not be valid)
* cid: current command ID (used for visibility test, and stored into
* tuple's cmax if lock is successful)
* mode: indicates if shared or exclusive tuple lock is desired
* nowait: if true, ereport rather than blocking if lock not available
*
* Output parameters:
* *tuple: all fields filled in
* *buffer: set to buffer holding tuple (pinned but not locked at exit)
* *ctid: set to tuple's t_ctid, but only in failure cases
* *update_xmax: set to tuple's xmax, but only in failure cases
*
* Function result may be:
* HeapTupleMayBeUpdated: lock was successfully acquired
* HeapTupleSelfUpdated: lock failed because tuple updated by self
* HeapTupleUpdated: lock failed because tuple updated by other xact
*
* In the failure cases, the routine returns the tuple's t_ctid and t_xmax.
* If t_ctid is the same as t_self, the tuple was deleted; if different, the
* tuple was updated, and t_ctid is the location of the replacement tuple.
* (t_xmax is needed to verify that the replacement tuple matches.)
*
*
* NOTES: because the shared-memory lock table is of finite size, but users
* could reasonably want to lock large numbers of tuples, we do not rely on
* the standard lock manager to store tuple-level locks over the long term.
* Instead, a tuple is marked as locked by setting the current transaction's
* XID as its XMAX, and setting additional infomask bits to distinguish this
* usage from the more normal case of having deleted the tuple. When
* multiple transactions concurrently share-lock a tuple, the first locker's
* XID is replaced in XMAX with a MultiTransactionId representing the set of
* XIDs currently holding share-locks.
*
* When it is necessary to wait for a tuple-level lock to be released, the
* basic delay is provided by XactLockTableWait or MultiXactIdWait on the
* contents of the tuple's XMAX. However, that mechanism will release all
* waiters concurrently, so there would be a race condition as to which
* waiter gets the tuple, potentially leading to indefinite starvation of
* some waiters. The possibility of share-locking makes the problem much
* worse --- a steady stream of share-lockers can easily block an exclusive
* locker forever. To provide more reliable semantics about who gets a
* tuple-level lock first, we use the standard lock manager. The protocol
* for waiting for a tuple-level lock is really
* LockTuple()
* XactLockTableWait()
* mark tuple as locked by me
* UnlockTuple()
* When there are multiple waiters, arbitration of who is to get the lock next
* is provided by LockTuple(). However, at most one tuple-level lock will
* be held or awaited per backend at any time, so we don't risk overflow
* of the lock table. Note that incoming share-lockers are required to
* do LockTuple as well, if there is any conflict, to ensure that they don't
* starve out waiting exclusive-lockers. However, if there is not any active
* conflict for a tuple, we don't incur any extra overhead.
*/
HTSU_Result
heap_lock_tuple(Relation relation, HeapTuple tuple, Buffer *buffer,
ItemPointer ctid, TransactionId *update_xmax,
CommandId cid, LockTupleMode mode, bool nowait)
{
HTSU_Result result;
ItemPointer tid = &(tuple->t_self);
ItemId lp;
PageHeader dp;
TransactionId xid;
TransactionId xmax;
uint16 old_infomask;
uint16 new_infomask;
LOCKMODE tuple_lock_type;
bool have_tuple_lock = false;
tuple_lock_type = (mode == LockTupleShared) ? ShareLock : ExclusiveLock;
*buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
dp = (PageHeader) BufferGetPage(*buffer);
lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
Assert(ItemIdIsUsed(lp));
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
tuple->t_len = ItemIdGetLength(lp);
tuple->t_tableOid = RelationGetRelid(relation);
l3:
result = HeapTupleSatisfiesUpdate(tuple->t_data, cid, *buffer);
if (result == HeapTupleInvisible)
{
UnlockReleaseBuffer(*buffer);
elog(ERROR, "attempted to lock invisible tuple");
}
else if (result == HeapTupleBeingUpdated)
{
TransactionId xwait;
uint16 infomask;
/* must copy state data before unlocking buffer */
xwait = HeapTupleHeaderGetXmax(tuple->t_data);
infomask = tuple->t_data->t_infomask;
LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
/*
* If we wish to acquire share lock, and the tuple is already
* share-locked by a multixact that includes any subtransaction of the
* current top transaction, then we effectively hold the desired lock
* already. We *must* succeed without trying to take the tuple lock,
* else we will deadlock against anyone waiting to acquire exclusive
* lock. We don't need to make any state changes in this case.
*/
if (mode == LockTupleShared &&
(infomask & HEAP_XMAX_IS_MULTI) &&
MultiXactIdIsCurrent((MultiXactId) xwait))
{
Assert(infomask & HEAP_XMAX_SHARED_LOCK);
/* Probably can't hold tuple lock here, but may as well check */
if (have_tuple_lock)
UnlockTuple(relation, tid, tuple_lock_type);
return HeapTupleMayBeUpdated;
}
/*
* Acquire tuple lock to establish our priority for the tuple.
* LockTuple will release us when we are next-in-line for the tuple.
* We must do this even if we are share-locking.
*
* If we are forced to "start over" below, we keep the tuple lock;
* this arranges that we stay at the head of the line while rechecking
* tuple state.
*/
if (!have_tuple_lock)
{
if (nowait)
{
if (!ConditionalLockTuple(relation, tid, tuple_lock_type))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
LockTuple(relation, tid, tuple_lock_type);
have_tuple_lock = true;
}
if (mode == LockTupleShared && (infomask & HEAP_XMAX_SHARED_LOCK))
{
/*
* Acquiring sharelock when there's at least one sharelocker
* already. We need not wait for him/them to complete.
*/
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* Make sure it's still a shared lock, else start over. (It's OK
* if the ownership of the shared lock has changed, though.)
*/
if (!(tuple->t_data->t_infomask & HEAP_XMAX_SHARED_LOCK))
goto l3;
}
else if (infomask & HEAP_XMAX_IS_MULTI)
{
/* wait for multixact to end */
if (nowait)
{
if (!ConditionalMultiXactIdWait((MultiXactId) xwait))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
MultiXactIdWait((MultiXactId) xwait);
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* If xwait had just locked the tuple then some other xact could
* update this tuple before we get to this point. Check for xmax
* change, and start over if so.
*/
if (!(tuple->t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(tuple->t_data),
xwait))
goto l3;
/*
* You might think the multixact is necessarily done here, but not
* so: it could have surviving members, namely our own xact or
* other subxacts of this backend. It is legal for us to lock the
* tuple in either case, however. We don't bother changing the
* on-disk hint bits since we are about to overwrite the xmax
* altogether.
*/
}
else
{
/* wait for regular transaction to end */
if (nowait)
{
if (!ConditionalXactLockTableWait(xwait))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
XactLockTableWait(xwait);
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
/*
* xwait is done, but if xwait had just locked the tuple then some
* other xact could update this tuple before we get to this point.
* Check for xmax change, and start over if so.
*/
if ((tuple->t_data->t_infomask & HEAP_XMAX_IS_MULTI) ||
!TransactionIdEquals(HeapTupleHeaderGetXmax(tuple->t_data),
xwait))
goto l3;
/* Otherwise we can mark it committed or aborted */
if (!(tuple->t_data->t_infomask & (HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID)))
{
if (TransactionIdDidCommit(xwait))
tuple->t_data->t_infomask |= HEAP_XMAX_COMMITTED;
else
tuple->t_data->t_infomask |= HEAP_XMAX_INVALID;
SetBufferCommitInfoNeedsSave(*buffer);
}
}
/*
* We may lock if previous xmax aborted, or if it committed but only
* locked the tuple without updating it. The case where we didn't
* wait because we are joining an existing shared lock is correctly
* handled, too.
*/
if (tuple->t_data->t_infomask & (HEAP_XMAX_INVALID |
HEAP_IS_LOCKED))
result = HeapTupleMayBeUpdated;
else
result = HeapTupleUpdated;
}
if (result != HeapTupleMayBeUpdated)
{
Assert(result == HeapTupleSelfUpdated || result == HeapTupleUpdated);
Assert(!(tuple->t_data->t_infomask & HEAP_XMAX_INVALID));
*ctid = tuple->t_data->t_ctid;
*update_xmax = HeapTupleHeaderGetXmax(tuple->t_data);
LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
if (have_tuple_lock)
UnlockTuple(relation, tid, tuple_lock_type);
return result;
}
/*
* We might already hold the desired lock (or stronger), possibly under
* a different subtransaction of the current top transaction. If so,
* there is no need to change state or issue a WAL record. We already
* handled the case where this is true for xmax being a MultiXactId,
* so now check for cases where it is a plain TransactionId.
*
* Note in particular that this covers the case where we already hold
* exclusive lock on the tuple and the caller only wants shared lock.
* It would certainly not do to give up the exclusive lock.
*/
xmax = HeapTupleHeaderGetXmax(tuple->t_data);
old_infomask = tuple->t_data->t_infomask;
if (!(old_infomask & (HEAP_XMAX_INVALID |
HEAP_XMAX_COMMITTED |
HEAP_XMAX_IS_MULTI)) &&
(mode == LockTupleShared ?
(old_infomask & HEAP_IS_LOCKED) :
(old_infomask & HEAP_XMAX_EXCL_LOCK)) &&
TransactionIdIsCurrentTransactionId(xmax))
{
LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
/* Probably can't hold tuple lock here, but may as well check */
if (have_tuple_lock)
UnlockTuple(relation, tid, tuple_lock_type);
return HeapTupleMayBeUpdated;
}
/*
* Compute the new xmax and infomask to store into the tuple. Note we do
* not modify the tuple just yet, because that would leave it in the wrong
* state if multixact.c elogs.
*/
xid = GetCurrentTransactionId();
new_infomask = old_infomask & ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
if (mode == LockTupleShared)
{
/*
* If this is the first acquisition of a shared lock in the current
* transaction, set my per-backend OldestMemberMXactId setting. We can
* be certain that the transaction will never become a member of any
* older MultiXactIds than that. (We have to do this even if we end
* up just using our own TransactionId below, since some other backend
* could incorporate our XID into a MultiXact immediately afterwards.)
*/
MultiXactIdSetOldestMember();
new_infomask |= HEAP_XMAX_SHARED_LOCK;
/*
* Check to see if we need a MultiXactId because there are multiple
* lockers.
*
* HeapTupleSatisfiesUpdate will have set the HEAP_XMAX_INVALID bit if
* the xmax was a MultiXactId but it was not running anymore. There is
* a race condition, which is that the MultiXactId may have finished
* since then, but that uncommon case is handled within
* MultiXactIdExpand.
*
* There is a similar race condition possible when the old xmax was a
* regular TransactionId. We test TransactionIdIsInProgress again
* just to narrow the window, but it's still possible to end up
* creating an unnecessary MultiXactId. Fortunately this is harmless.
*/
if (!(old_infomask & (HEAP_XMAX_INVALID | HEAP_XMAX_COMMITTED)))
{
if (old_infomask & HEAP_XMAX_IS_MULTI)
{
/*
* If the XMAX is already a MultiXactId, then we need to
* expand it to include our own TransactionId.
*/
xid = MultiXactIdExpand((MultiXactId) xmax, xid);
new_infomask |= HEAP_XMAX_IS_MULTI;
}
else if (TransactionIdIsInProgress(xmax))
{
/*
* If the XMAX is a valid TransactionId, then we need to
* create a new MultiXactId that includes both the old
* locker and our own TransactionId.
*/
xid = MultiXactIdCreate(xmax, xid);
new_infomask |= HEAP_XMAX_IS_MULTI;
}
else
{
/*
* Can get here iff HeapTupleSatisfiesUpdate saw the old xmax
* as running, but it finished before
* TransactionIdIsInProgress() got to run. Treat it like
* there's no locker in the tuple.
*/
}
}
else
{
/*
* There was no previous locker, so just insert our own
* TransactionId.
*/
}
}
else
{
/* We want an exclusive lock on the tuple */
new_infomask |= HEAP_XMAX_EXCL_LOCK;
}
START_CRIT_SECTION();
/*
* Store transaction information of xact locking the tuple.
*
* Note: Cmax is meaningless in this context, so don't set it; this
* avoids possibly generating a useless combo CID.
*/
tuple->t_data->t_infomask = new_infomask;
HeapTupleHeaderSetXmax(tuple->t_data, xid);
/* Make sure there is no forward chain link in t_ctid */
tuple->t_data->t_ctid = *tid;
MarkBufferDirty(*buffer);
/*
* XLOG stuff. You might think that we don't need an XLOG record because
* there is no state change worth restoring after a crash. You would be
* wrong however: we have just written either a TransactionId or a
* MultiXactId that may never have been seen on disk before, and we need
* to make sure that there are XLOG entries covering those ID numbers.
* Else the same IDs might be re-used after a crash, which would be
* disastrous if this page made it to disk before the crash. Essentially
* we have to enforce the WAL log-before-data rule even in this case.
* (Also, in a PITR log-shipping or 2PC environment, we have to have XLOG
* entries for everything anyway.)
*/
if (!relation->rd_istemp)
{
xl_heap_lock xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
xlrec.target.node = relation->rd_node;
xlrec.target.tid = tuple->t_self;
xlrec.locking_xid = xid;
xlrec.xid_is_mxact = ((new_infomask & HEAP_XMAX_IS_MULTI) != 0);
xlrec.shared_lock = (mode == LockTupleShared);
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapLock;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
rdata[1].data = NULL;
rdata[1].len = 0;
rdata[1].buffer = *buffer;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_LOCK, rdata);
PageSetLSN(dp, recptr);
PageSetTLI(dp, ThisTimeLineID);
}
else
{
/* No XLOG record, but still need to flag that XID exists on disk */
MyXactMadeTempRelUpdate = true;
}
END_CRIT_SECTION();
LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
/*
* Now that we have successfully marked the tuple as locked, we can
* release the lmgr tuple lock, if we had it.
*/
if (have_tuple_lock)
UnlockTuple(relation, tid, tuple_lock_type);
return HeapTupleMayBeUpdated;
}
/*
* heap_inplace_update - update a tuple "in place" (ie, overwrite it)
*
* Overwriting violates both MVCC and transactional safety, so the uses
* of this function in Postgres are extremely limited. Nonetheless we
* find some places to use it.
*
* The tuple cannot change size, and therefore it's reasonable to assume
* that its null bitmap (if any) doesn't change either. So we just
* overwrite the data portion of the tuple without touching the null
* bitmap or any of the header fields.
*
* tuple is an in-memory tuple structure containing the data to be written
* over the target tuple. Also, tuple->t_self identifies the target tuple.
*/
void
heap_inplace_update(Relation relation, HeapTuple tuple)
{
Buffer buffer;
Page page;
OffsetNumber offnum;
ItemId lp = NULL;
HeapTupleHeader htup;
uint32 oldlen;
uint32 newlen;
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&(tuple->t_self)));
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
offnum = ItemPointerGetOffsetNumber(&(tuple->t_self));
if (PageGetMaxOffsetNumber(page) >= offnum)
lp = PageGetItemId(page, offnum);
if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsUsed(lp))
elog(ERROR, "heap_inplace_update: invalid lp");
htup = (HeapTupleHeader) PageGetItem(page, lp);
oldlen = ItemIdGetLength(lp) - htup->t_hoff;
newlen = tuple->t_len - tuple->t_data->t_hoff;
if (oldlen != newlen || htup->t_hoff != tuple->t_data->t_hoff)
elog(ERROR, "heap_inplace_update: wrong tuple length");
/* NO EREPORT(ERROR) from here till changes are logged */
START_CRIT_SECTION();
memcpy((char *) htup + htup->t_hoff,
(char *) tuple->t_data + tuple->t_data->t_hoff,
newlen);
MarkBufferDirty(buffer);
/* XLOG stuff */
if (!relation->rd_istemp)
{
xl_heap_inplace xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
xlrec.target.node = relation->rd_node;
xlrec.target.tid = tuple->t_self;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapInplace;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
rdata[1].data = (char *) htup + htup->t_hoff;
rdata[1].len = newlen;
rdata[1].buffer = buffer;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_INPLACE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buffer);
/* Send out shared cache inval if necessary */
if (!IsBootstrapProcessingMode())
CacheInvalidateHeapTuple(relation, tuple);
}
/*
* heap_freeze_tuple
*
* Check to see whether any of the XID fields of a tuple (xmin, xmax, xvac)
* are older than the specified cutoff XID. If so, replace them with
* FrozenTransactionId or InvalidTransactionId as appropriate, and return
* TRUE. Return FALSE if nothing was changed.
*
* It is assumed that the caller has checked the tuple with
* HeapTupleSatisfiesVacuum() and determined that it is not HEAPTUPLE_DEAD
* (else we should be removing the tuple, not freezing it).
*
* NB: cutoff_xid *must* be <= the current global xmin, to ensure that any
* XID older than it could neither be running nor seen as running by any
* open transaction. This ensures that the replacement will not change
* anyone's idea of the tuple state. Also, since we assume the tuple is
* not HEAPTUPLE_DEAD, the fact that an XID is not still running allows us
* to assume that it is either committed good or aborted, as appropriate;
* so we need no external state checks to decide what to do. (This is good
* because this function is applied during WAL recovery, when we don't have
* access to any such state, and can't depend on the hint bits to be set.)
*
* In lazy VACUUM, we call this while initially holding only a shared lock
* on the tuple's buffer. If any change is needed, we trade that in for an
* exclusive lock before making the change. Caller should pass the buffer ID
* if shared lock is held, InvalidBuffer if exclusive lock is already held.
*
* Note: it might seem we could make the changes without exclusive lock, since
* TransactionId read/write is assumed atomic anyway. However there is a race
* condition: someone who just fetched an old XID that we overwrite here could
* conceivably not finish checking the XID against pg_clog before we finish
* the VACUUM and perhaps truncate off the part of pg_clog he needs. Getting
* exclusive lock ensures no other backend is in process of checking the
* tuple status. Also, getting exclusive lock makes it safe to adjust the
* infomask bits.
*/
bool
heap_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
Buffer buf)
{
bool changed = false;
TransactionId xid;
xid = HeapTupleHeaderGetXmin(tuple);
if (TransactionIdIsNormal(xid) &&
TransactionIdPrecedes(xid, cutoff_xid))
{
if (buf != InvalidBuffer)
{
/* trade in share lock for exclusive lock */
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
buf = InvalidBuffer;
}
HeapTupleHeaderSetXmin(tuple, FrozenTransactionId);
/*
* Might as well fix the hint bits too; usually XMIN_COMMITTED will
* already be set here, but there's a small chance not.
*/
Assert(!(tuple->t_infomask & HEAP_XMIN_INVALID));
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
changed = true;
}
/*
* When we release shared lock, it's possible for someone else to change
* xmax before we get the lock back, so repeat the check after acquiring
* exclusive lock. (We don't need this pushup for xmin, because only
* VACUUM could be interested in changing an existing tuple's xmin,
* and there's only one VACUUM allowed on a table at a time.)
*/
recheck_xmax:
if (!(tuple->t_infomask & HEAP_XMAX_IS_MULTI))
{
xid = HeapTupleHeaderGetXmax(tuple);
if (TransactionIdIsNormal(xid) &&
TransactionIdPrecedes(xid, cutoff_xid))
{
if (buf != InvalidBuffer)
{
/* trade in share lock for exclusive lock */
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
buf = InvalidBuffer;
goto recheck_xmax; /* see comment above */
}
HeapTupleHeaderSetXmax(tuple, InvalidTransactionId);
/*
* The tuple might be marked either XMAX_INVALID or
* XMAX_COMMITTED + LOCKED. Normalize to INVALID just to be
* sure no one gets confused.
*/
tuple->t_infomask &= ~HEAP_XMAX_COMMITTED;
tuple->t_infomask |= HEAP_XMAX_INVALID;
changed = true;
}
}
else
{
/*----------
* XXX perhaps someday we should zero out very old MultiXactIds here?
*
* The only way a stale MultiXactId could pose a problem is if a
* tuple, having once been multiply-share-locked, is not touched by
* any vacuum or attempted lock or deletion for just over 4G MultiXact
* creations, and then in the probably-narrow window where its xmax
* is again a live MultiXactId, someone tries to lock or delete it.
* Even then, another share-lock attempt would work fine. An
* exclusive-lock or delete attempt would face unexpected delay, or
* in the very worst case get a deadlock error. This seems an
* extremely low-probability scenario with minimal downside even if
* it does happen, so for now we don't do the extra bookkeeping that
* would be needed to clean out MultiXactIds.
*----------
*/
}
/*
* Although xvac per se could only be set by VACUUM, it shares physical
* storage space with cmax, and so could be wiped out by someone setting
* xmax. Hence recheck after changing lock, same as for xmax itself.
*/
recheck_xvac:
if (tuple->t_infomask & HEAP_MOVED)
{
xid = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsNormal(xid) &&
TransactionIdPrecedes(xid, cutoff_xid))
{
if (buf != InvalidBuffer)
{
/* trade in share lock for exclusive lock */
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
buf = InvalidBuffer;
goto recheck_xvac; /* see comment above */
}
/*
* If a MOVED_OFF tuple is not dead, the xvac transaction must
* have failed; whereas a non-dead MOVED_IN tuple must mean the
* xvac transaction succeeded.
*/
if (tuple->t_infomask & HEAP_MOVED_OFF)
HeapTupleHeaderSetXvac(tuple, InvalidTransactionId);
else
HeapTupleHeaderSetXvac(tuple, FrozenTransactionId);
/*
* Might as well fix the hint bits too; usually XMIN_COMMITTED will
* already be set here, but there's a small chance not.
*/
Assert(!(tuple->t_infomask & HEAP_XMIN_INVALID));
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
changed = true;
}
}
return changed;
}
/* ----------------
* heap_markpos - mark scan position
* ----------------
*/
void
heap_markpos(HeapScanDesc scan)
{
/* Note: no locking manipulations needed */
if (scan->rs_ctup.t_data != NULL)
{
scan->rs_mctid = scan->rs_ctup.t_self;
if (scan->rs_pageatatime)
scan->rs_mindex = scan->rs_cindex;
}
else
ItemPointerSetInvalid(&scan->rs_mctid);
}
/* ----------------
* heap_restrpos - restore position to marked location
* ----------------
*/
void
heap_restrpos(HeapScanDesc scan)
{
/* XXX no amrestrpos checking that ammarkpos called */
if (!ItemPointerIsValid(&scan->rs_mctid))
{
scan->rs_ctup.t_data = NULL;
/*
* unpin scan buffers
*/
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
scan->rs_cbuf = InvalidBuffer;
scan->rs_cblock = InvalidBlockNumber;
scan->rs_inited = false;
}
else
{
/*
* If we reached end of scan, rs_inited will now be false. We must
* reset it to true to keep heapgettup from doing the wrong thing.
*/
scan->rs_inited = true;
scan->rs_ctup.t_self = scan->rs_mctid;
if (scan->rs_pageatatime)
{
scan->rs_cindex = scan->rs_mindex;
heapgettup_pagemode(scan,
NoMovementScanDirection,
0, /* needn't recheck scan keys */
NULL);
}
else
heapgettup(scan,
NoMovementScanDirection,
0, /* needn't recheck scan keys */
NULL);
}
}
/*
* Perform XLogInsert for a heap-clean operation. Caller must already
* have modified the buffer and marked it dirty.
*
* Note: for historical reasons, the entries in the unused[] array should
* be zero-based tuple indexes, not one-based.
*/
XLogRecPtr
log_heap_clean(Relation reln, Buffer buffer, OffsetNumber *unused, int uncnt)
{
xl_heap_clean xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
/* Caller should not call me on a temp relation */
Assert(!reln->rd_istemp);
xlrec.node = reln->rd_node;
xlrec.block = BufferGetBlockNumber(buffer);
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapClean;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* The unused-offsets array is not actually in the buffer, but pretend
* that it is. When XLogInsert stores the whole buffer, the offsets array
* need not be stored too.
*/
if (uncnt > 0)
{
rdata[1].data = (char *) unused;
rdata[1].len = uncnt * sizeof(OffsetNumber);
}
else
{
rdata[1].data = NULL;
rdata[1].len = 0;
}
rdata[1].buffer = buffer;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_CLEAN, rdata);
return recptr;
}
/*
* Perform XLogInsert for a heap-freeze operation. Caller must already
* have modified the buffer and marked it dirty.
*
* Unlike log_heap_clean(), the offsets[] entries are one-based.
*/
XLogRecPtr
log_heap_freeze(Relation reln, Buffer buffer,
TransactionId cutoff_xid,
OffsetNumber *offsets, int offcnt)
{
xl_heap_freeze xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
/* Caller should not call me on a temp relation */
Assert(!reln->rd_istemp);
xlrec.node = reln->rd_node;
xlrec.block = BufferGetBlockNumber(buffer);
xlrec.cutoff_xid = cutoff_xid;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapFreeze;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
/*
* The tuple-offsets array is not actually in the buffer, but pretend
* that it is. When XLogInsert stores the whole buffer, the offsets array
* need not be stored too.
*/
if (offcnt > 0)
{
rdata[1].data = (char *) offsets;
rdata[1].len = offcnt * sizeof(OffsetNumber);
}
else
{
rdata[1].data = NULL;
rdata[1].len = 0;
}
rdata[1].buffer = buffer;
rdata[1].buffer_std = true;
rdata[1].next = NULL;
recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE, rdata);
return recptr;
}
/*
* Perform XLogInsert for a heap-update operation. Caller must already
* have modified the buffer(s) and marked them dirty.
*/
static XLogRecPtr
log_heap_update(Relation reln, Buffer oldbuf, ItemPointerData from,
Buffer newbuf, HeapTuple newtup, bool move)
{
/*
* Note: xlhdr is declared to have adequate size and correct alignment for
* an xl_heap_header. However the two tids, if present at all, will be
* packed in with no wasted space after the xl_heap_header; they aren't
* necessarily aligned as implied by this struct declaration.
*/
struct
{
xl_heap_header hdr;
TransactionId tid1;
TransactionId tid2;
} xlhdr;
int hsize = SizeOfHeapHeader;
xl_heap_update xlrec;
XLogRecPtr recptr;
XLogRecData rdata[4];
Page page = BufferGetPage(newbuf);
uint8 info = (move) ? XLOG_HEAP_MOVE : XLOG_HEAP_UPDATE;
/* Caller should not call me on a temp relation */
Assert(!reln->rd_istemp);
xlrec.target.node = reln->rd_node;
xlrec.target.tid = from;
xlrec.newtid = newtup->t_self;
rdata[0].data = (char *) &xlrec;
rdata[0].len = SizeOfHeapUpdate;
rdata[0].buffer = InvalidBuffer;
rdata[0].next = &(rdata[1]);
rdata[1].data = NULL;
rdata[1].len = 0;
rdata[1].buffer = oldbuf;
rdata[1].buffer_std = true;
rdata[1].next = &(rdata[2]);
xlhdr.hdr.t_infomask2 = newtup->t_data->t_infomask2;
xlhdr.hdr.t_infomask = newtup->t_data->t_infomask;
xlhdr.hdr.t_hoff = newtup->t_data->t_hoff;
if (move) /* remember xmax & xmin */
{
TransactionId xid[2]; /* xmax, xmin */
if (newtup->t_data->t_infomask & (HEAP_XMAX_INVALID | HEAP_IS_LOCKED))
xid[0] = InvalidTransactionId;
else
xid[0] = HeapTupleHeaderGetXmax(newtup->t_data);
xid[1] = HeapTupleHeaderGetXmin(newtup->t_data);
memcpy((char *) &xlhdr + hsize,
(char *) xid,
2 * sizeof(TransactionId));
hsize += 2 * sizeof(TransactionId);
}
/*
* As with insert records, we need not store the rdata[2] segment if we
* decide to store the whole buffer instead.
*/
rdata[2].data = (char *) &xlhdr;
rdata[2].len = hsize;
rdata[2].buffer = newbuf;
rdata[2].buffer_std = true;
rdata[2].next = &(rdata[3]);
/* PG73FORMAT: write bitmap [+ padding] [+ oid] + data */
rdata[3].data = (char *) newtup->t_data + offsetof(HeapTupleHeaderData, t_bits);
rdata[3].len = newtup->t_len - offsetof(HeapTupleHeaderData, t_bits);
rdata[3].buffer = newbuf;
rdata[3].buffer_std = true;
rdata[3].next = NULL;
/* If new tuple is the single and first tuple on page... */
if (ItemPointerGetOffsetNumber(&(newtup->t_self)) == FirstOffsetNumber &&
PageGetMaxOffsetNumber(page) == FirstOffsetNumber)
{
info |= XLOG_HEAP_INIT_PAGE;
rdata[2].buffer = rdata[3].buffer = InvalidBuffer;
}
recptr = XLogInsert(RM_HEAP_ID, info, rdata);
return recptr;
}
/*
* Perform XLogInsert for a heap-move operation. Caller must already
* have modified the buffers and marked them dirty.
*/
XLogRecPtr
log_heap_move(Relation reln, Buffer oldbuf, ItemPointerData from,
Buffer newbuf, HeapTuple newtup)
{
return log_heap_update(reln, oldbuf, from, newbuf, newtup, true);
}
static void
heap_xlog_clean(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_clean *xlrec = (xl_heap_clean *) XLogRecGetData(record);
Relation reln;
Buffer buffer;
Page page;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
reln = XLogOpenRelation(xlrec->node);
buffer = XLogReadBuffer(reln, xlrec->block, false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page)))
{
UnlockReleaseBuffer(buffer);
return;
}
if (record->xl_len > SizeOfHeapClean)
{
OffsetNumber *unused;
OffsetNumber *unend;
ItemId lp;
unused = (OffsetNumber *) ((char *) xlrec + SizeOfHeapClean);
unend = (OffsetNumber *) ((char *) xlrec + record->xl_len);
while (unused < unend)
{
/* unused[] entries are zero-based */
lp = PageGetItemId(page, *unused + 1);
lp->lp_flags &= ~LP_USED;
unused++;
}
}
PageRepairFragmentation(page, NULL);
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_freeze(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_freeze *xlrec = (xl_heap_freeze *) XLogRecGetData(record);
TransactionId cutoff_xid = xlrec->cutoff_xid;
Relation reln;
Buffer buffer;
Page page;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
reln = XLogOpenRelation(xlrec->node);
buffer = XLogReadBuffer(reln, xlrec->block, false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page)))
{
UnlockReleaseBuffer(buffer);
return;
}
if (record->xl_len > SizeOfHeapFreeze)
{
OffsetNumber *offsets;
OffsetNumber *offsets_end;
offsets = (OffsetNumber *) ((char *) xlrec + SizeOfHeapFreeze);
offsets_end = (OffsetNumber *) ((char *) xlrec + record->xl_len);
while (offsets < offsets_end)
{
/* offsets[] entries are one-based */
ItemId lp = PageGetItemId(page, *offsets);
HeapTupleHeader tuple = (HeapTupleHeader) PageGetItem(page, lp);
(void) heap_freeze_tuple(tuple, cutoff_xid, InvalidBuffer);
offsets++;
}
}
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_newpage(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_newpage *xlrec = (xl_heap_newpage *) XLogRecGetData(record);
Relation reln;
Buffer buffer;
Page page;
/*
* Note: the NEWPAGE log record is used for both heaps and indexes, so do
* not do anything that assumes we are touching a heap.
*/
reln = XLogOpenRelation(xlrec->node);
buffer = XLogReadBuffer(reln, xlrec->blkno, true);
Assert(BufferIsValid(buffer));
page = (Page) BufferGetPage(buffer);
Assert(record->xl_len == SizeOfHeapNewpage + BLCKSZ);
memcpy(page, (char *) xlrec + SizeOfHeapNewpage, BLCKSZ);
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_delete *xlrec = (xl_heap_delete *) XLogRecGetData(record);
Relation reln;
Buffer buffer;
Page page;
OffsetNumber offnum;
ItemId lp = NULL;
HeapTupleHeader htup;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
reln = XLogOpenRelation(xlrec->target.node);
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
return;
}
offnum = ItemPointerGetOffsetNumber(&(xlrec->target.tid));
if (PageGetMaxOffsetNumber(page) >= offnum)
lp = PageGetItemId(page, offnum);
if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsUsed(lp))
elog(PANIC, "heap_delete_redo: invalid lp");
htup = (HeapTupleHeader) PageGetItem(page, lp);
htup->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
HeapTupleHeaderSetXmax(htup, record->xl_xid);
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
/* Make sure there is no forward chain link in t_ctid */
htup->t_ctid = xlrec->target.tid;
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_insert(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_insert *xlrec = (xl_heap_insert *) XLogRecGetData(record);
Relation reln;
Buffer buffer;
Page page;
OffsetNumber offnum;
struct
{
HeapTupleHeaderData hdr;
char data[MaxHeapTupleSize];
} tbuf;
HeapTupleHeader htup;
xl_heap_header xlhdr;
uint32 newlen;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
reln = XLogOpenRelation(xlrec->target.node);
if (record->xl_info & XLOG_HEAP_INIT_PAGE)
{
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
true);
Assert(BufferIsValid(buffer));
page = (Page) BufferGetPage(buffer);
PageInit(page, BufferGetPageSize(buffer), 0);
}
else
{
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
return;
}
}
offnum = ItemPointerGetOffsetNumber(&(xlrec->target.tid));
if (PageGetMaxOffsetNumber(page) + 1 < offnum)
elog(PANIC, "heap_insert_redo: invalid max offset number");
newlen = record->xl_len - SizeOfHeapInsert - SizeOfHeapHeader;
Assert(newlen <= MaxHeapTupleSize);
memcpy((char *) &xlhdr,
(char *) xlrec + SizeOfHeapInsert,
SizeOfHeapHeader);
htup = &tbuf.hdr;
MemSet((char *) htup, 0, sizeof(HeapTupleHeaderData));
/* PG73FORMAT: get bitmap [+ padding] [+ oid] + data */
memcpy((char *) htup + offsetof(HeapTupleHeaderData, t_bits),
(char *) xlrec + SizeOfHeapInsert + SizeOfHeapHeader,
newlen);
newlen += offsetof(HeapTupleHeaderData, t_bits);
htup->t_infomask2 = xlhdr.t_infomask2;
htup->t_infomask = xlhdr.t_infomask;
htup->t_hoff = xlhdr.t_hoff;
HeapTupleHeaderSetXmin(htup, record->xl_xid);
HeapTupleHeaderSetCmin(htup, FirstCommandId);
htup->t_ctid = xlrec->target.tid;
offnum = PageAddItem(page, (Item) htup, newlen, offnum,
LP_USED | OverwritePageMode);
if (offnum == InvalidOffsetNumber)
elog(PANIC, "heap_insert_redo: failed to add tuple");
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
/*
* Handles UPDATE & MOVE
*/
static void
heap_xlog_update(XLogRecPtr lsn, XLogRecord *record, bool move)
{
xl_heap_update *xlrec = (xl_heap_update *) XLogRecGetData(record);
Relation reln = XLogOpenRelation(xlrec->target.node);
Buffer buffer;
bool samepage = (ItemPointerGetBlockNumber(&(xlrec->newtid)) ==
ItemPointerGetBlockNumber(&(xlrec->target.tid)));
Page page;
OffsetNumber offnum;
ItemId lp = NULL;
HeapTupleHeader htup;
struct
{
HeapTupleHeaderData hdr;
char data[MaxHeapTupleSize];
} tbuf;
xl_heap_header xlhdr;
int hsize;
uint32 newlen;
if (record->xl_info & XLR_BKP_BLOCK_1)
{
if (samepage)
return; /* backup block covered both changes */
goto newt;
}
/* Deal with old tuple version */
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
false);
if (!BufferIsValid(buffer))
goto newt;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
if (samepage)
return;
goto newt;
}
offnum = ItemPointerGetOffsetNumber(&(xlrec->target.tid));
if (PageGetMaxOffsetNumber(page) >= offnum)
lp = PageGetItemId(page, offnum);
if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsUsed(lp))
elog(PANIC, "heap_update_redo: invalid lp");
htup = (HeapTupleHeader) PageGetItem(page, lp);
if (move)
{
htup->t_infomask &= ~(HEAP_XMIN_COMMITTED |
HEAP_XMIN_INVALID |
HEAP_MOVED_IN);
htup->t_infomask |= HEAP_MOVED_OFF;
HeapTupleHeaderSetXvac(htup, record->xl_xid);
/* Make sure there is no forward chain link in t_ctid */
htup->t_ctid = xlrec->target.tid;
}
else
{
htup->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
HeapTupleHeaderSetXmax(htup, record->xl_xid);
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
/* Set forward chain link in t_ctid */
htup->t_ctid = xlrec->newtid;
}
/*
* this test is ugly, but necessary to avoid thinking that insert change
* is already applied
*/
if (samepage)
goto newsame;
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
/* Deal with new tuple */
newt:;
if (record->xl_info & XLR_BKP_BLOCK_2)
return;
if (record->xl_info & XLOG_HEAP_INIT_PAGE)
{
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->newtid)),
true);
Assert(BufferIsValid(buffer));
page = (Page) BufferGetPage(buffer);
PageInit(page, BufferGetPageSize(buffer), 0);
}
else
{
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->newtid)),
false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
return;
}
}
newsame:;
offnum = ItemPointerGetOffsetNumber(&(xlrec->newtid));
if (PageGetMaxOffsetNumber(page) + 1 < offnum)
elog(PANIC, "heap_update_redo: invalid max offset number");
hsize = SizeOfHeapUpdate + SizeOfHeapHeader;
if (move)
hsize += (2 * sizeof(TransactionId));
newlen = record->xl_len - hsize;
Assert(newlen <= MaxHeapTupleSize);
memcpy((char *) &xlhdr,
(char *) xlrec + SizeOfHeapUpdate,
SizeOfHeapHeader);
htup = &tbuf.hdr;
MemSet((char *) htup, 0, sizeof(HeapTupleHeaderData));
/* PG73FORMAT: get bitmap [+ padding] [+ oid] + data */
memcpy((char *) htup + offsetof(HeapTupleHeaderData, t_bits),
(char *) xlrec + hsize,
newlen);
newlen += offsetof(HeapTupleHeaderData, t_bits);
htup->t_infomask2 = xlhdr.t_infomask2;
htup->t_infomask = xlhdr.t_infomask;
htup->t_hoff = xlhdr.t_hoff;
if (move)
{
TransactionId xid[2]; /* xmax, xmin */
memcpy((char *) xid,
(char *) xlrec + SizeOfHeapUpdate + SizeOfHeapHeader,
2 * sizeof(TransactionId));
HeapTupleHeaderSetXmin(htup, xid[1]);
HeapTupleHeaderSetXmax(htup, xid[0]);
HeapTupleHeaderSetXvac(htup, record->xl_xid);
}
else
{
HeapTupleHeaderSetXmin(htup, record->xl_xid);
HeapTupleHeaderSetCmin(htup, FirstCommandId);
}
/* Make sure there is no forward chain link in t_ctid */
htup->t_ctid = xlrec->newtid;
offnum = PageAddItem(page, (Item) htup, newlen, offnum,
LP_USED | OverwritePageMode);
if (offnum == InvalidOffsetNumber)
elog(PANIC, "heap_update_redo: failed to add tuple");
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_lock(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_lock *xlrec = (xl_heap_lock *) XLogRecGetData(record);
Relation reln;
Buffer buffer;
Page page;
OffsetNumber offnum;
ItemId lp = NULL;
HeapTupleHeader htup;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
reln = XLogOpenRelation(xlrec->target.node);
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
return;
}
offnum = ItemPointerGetOffsetNumber(&(xlrec->target.tid));
if (PageGetMaxOffsetNumber(page) >= offnum)
lp = PageGetItemId(page, offnum);
if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsUsed(lp))
elog(PANIC, "heap_lock_redo: invalid lp");
htup = (HeapTupleHeader) PageGetItem(page, lp);
htup->t_infomask &= ~(HEAP_XMAX_COMMITTED |
HEAP_XMAX_INVALID |
HEAP_XMAX_IS_MULTI |
HEAP_IS_LOCKED |
HEAP_MOVED);
if (xlrec->xid_is_mxact)
htup->t_infomask |= HEAP_XMAX_IS_MULTI;
if (xlrec->shared_lock)
htup->t_infomask |= HEAP_XMAX_SHARED_LOCK;
else
htup->t_infomask |= HEAP_XMAX_EXCL_LOCK;
HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
/* Make sure there is no forward chain link in t_ctid */
htup->t_ctid = xlrec->target.tid;
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
static void
heap_xlog_inplace(XLogRecPtr lsn, XLogRecord *record)
{
xl_heap_inplace *xlrec = (xl_heap_inplace *) XLogRecGetData(record);
Relation reln = XLogOpenRelation(xlrec->target.node);
Buffer buffer;
Page page;
OffsetNumber offnum;
ItemId lp = NULL;
HeapTupleHeader htup;
uint32 oldlen;
uint32 newlen;
if (record->xl_info & XLR_BKP_BLOCK_1)
return;
buffer = XLogReadBuffer(reln,
ItemPointerGetBlockNumber(&(xlrec->target.tid)),
false);
if (!BufferIsValid(buffer))
return;
page = (Page) BufferGetPage(buffer);
if (XLByteLE(lsn, PageGetLSN(page))) /* changes are applied */
{
UnlockReleaseBuffer(buffer);
return;
}
offnum = ItemPointerGetOffsetNumber(&(xlrec->target.tid));
if (PageGetMaxOffsetNumber(page) >= offnum)
lp = PageGetItemId(page, offnum);
if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsUsed(lp))
elog(PANIC, "heap_inplace_redo: invalid lp");
htup = (HeapTupleHeader) PageGetItem(page, lp);
oldlen = ItemIdGetLength(lp) - htup->t_hoff;
newlen = record->xl_len - SizeOfHeapInplace;
if (oldlen != newlen)
elog(PANIC, "heap_inplace_redo: wrong tuple length");
memcpy((char *) htup + htup->t_hoff,
(char *) xlrec + SizeOfHeapInplace,
newlen);
PageSetLSN(page, lsn);
PageSetTLI(page, ThisTimeLineID);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
}
void
heap_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
info &= XLOG_HEAP_OPMASK;
if (info == XLOG_HEAP_INSERT)
heap_xlog_insert(lsn, record);
else if (info == XLOG_HEAP_DELETE)
heap_xlog_delete(lsn, record);
else if (info == XLOG_HEAP_UPDATE)
heap_xlog_update(lsn, record, false);
else if (info == XLOG_HEAP_MOVE)
heap_xlog_update(lsn, record, true);
else if (info == XLOG_HEAP_CLEAN)
heap_xlog_clean(lsn, record);
else if (info == XLOG_HEAP_NEWPAGE)
heap_xlog_newpage(lsn, record);
else if (info == XLOG_HEAP_LOCK)
heap_xlog_lock(lsn, record);
else if (info == XLOG_HEAP_INPLACE)
heap_xlog_inplace(lsn, record);
else
elog(PANIC, "heap_redo: unknown op code %u", info);
}
void
heap2_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
info &= XLOG_HEAP_OPMASK;
if (info == XLOG_HEAP2_FREEZE)
heap_xlog_freeze(lsn, record);
else
elog(PANIC, "heap2_redo: unknown op code %u", info);
}
static void
out_target(StringInfo buf, xl_heaptid *target)
{
appendStringInfo(buf, "rel %u/%u/%u; tid %u/%u",
target->node.spcNode, target->node.dbNode, target->node.relNode,
ItemPointerGetBlockNumber(&(target->tid)),
ItemPointerGetOffsetNumber(&(target->tid)));
}
void
heap_desc(StringInfo buf, uint8 xl_info, char *rec)
{
uint8 info = xl_info & ~XLR_INFO_MASK;
info &= XLOG_HEAP_OPMASK;
if (info == XLOG_HEAP_INSERT)
{
xl_heap_insert *xlrec = (xl_heap_insert *) rec;
if (xl_info & XLOG_HEAP_INIT_PAGE)
appendStringInfo(buf, "insert(init): ");
else
appendStringInfo(buf, "insert: ");
out_target(buf, &(xlrec->target));
}
else if (info == XLOG_HEAP_DELETE)
{
xl_heap_delete *xlrec = (xl_heap_delete *) rec;
appendStringInfo(buf, "delete: ");
out_target(buf, &(xlrec->target));
}
else if (info == XLOG_HEAP_UPDATE)
{
xl_heap_update *xlrec = (xl_heap_update *) rec;
if (xl_info & XLOG_HEAP_INIT_PAGE)
appendStringInfo(buf, "update(init): ");
else
appendStringInfo(buf, "update: ");
out_target(buf, &(xlrec->target));
appendStringInfo(buf, "; new %u/%u",
ItemPointerGetBlockNumber(&(xlrec->newtid)),
ItemPointerGetOffsetNumber(&(xlrec->newtid)));
}
else if (info == XLOG_HEAP_MOVE)
{
xl_heap_update *xlrec = (xl_heap_update *) rec;
if (xl_info & XLOG_HEAP_INIT_PAGE)
appendStringInfo(buf, "move(init): ");
else
appendStringInfo(buf, "move: ");
out_target(buf, &(xlrec->target));
appendStringInfo(buf, "; new %u/%u",
ItemPointerGetBlockNumber(&(xlrec->newtid)),
ItemPointerGetOffsetNumber(&(xlrec->newtid)));
}
else if (info == XLOG_HEAP_CLEAN)
{
xl_heap_clean *xlrec = (xl_heap_clean *) rec;
appendStringInfo(buf, "clean: rel %u/%u/%u; blk %u",
xlrec->node.spcNode, xlrec->node.dbNode,
xlrec->node.relNode, xlrec->block);
}
else if (info == XLOG_HEAP_NEWPAGE)
{
xl_heap_newpage *xlrec = (xl_heap_newpage *) rec;
appendStringInfo(buf, "newpage: rel %u/%u/%u; blk %u",
xlrec->node.spcNode, xlrec->node.dbNode,
xlrec->node.relNode, xlrec->blkno);
}
else if (info == XLOG_HEAP_LOCK)
{
xl_heap_lock *xlrec = (xl_heap_lock *) rec;
if (xlrec->shared_lock)
appendStringInfo(buf, "shared_lock: ");
else
appendStringInfo(buf, "exclusive_lock: ");
if (xlrec->xid_is_mxact)
appendStringInfo(buf, "mxid ");
else
appendStringInfo(buf, "xid ");
appendStringInfo(buf, "%u ", xlrec->locking_xid);
out_target(buf, &(xlrec->target));
}
else if (info == XLOG_HEAP_INPLACE)
{
xl_heap_inplace *xlrec = (xl_heap_inplace *) rec;
appendStringInfo(buf, "inplace: ");
out_target(buf, &(xlrec->target));
}
else
appendStringInfo(buf, "UNKNOWN");
}
void
heap2_desc(StringInfo buf, uint8 xl_info, char *rec)
{
uint8 info = xl_info & ~XLR_INFO_MASK;
info &= XLOG_HEAP_OPMASK;
if (info == XLOG_HEAP2_FREEZE)
{
xl_heap_freeze *xlrec = (xl_heap_freeze *) rec;
appendStringInfo(buf, "freeze: rel %u/%u/%u; blk %u; cutoff %u",
xlrec->node.spcNode, xlrec->node.dbNode,
xlrec->node.relNode, xlrec->block,
xlrec->cutoff_xid);
}
else
appendStringInfo(buf, "UNKNOWN");
}
/*
* heap_sync - sync a heap, for use when no WAL has been written
*
* This forces the heap contents (including TOAST heap if any) down to disk.
* If we skipped using WAL, and it's not a temp relation, we must force the
* relation down to disk before it's safe to commit the transaction. This
* requires writing out any dirty buffers and then doing a forced fsync.
*
* Indexes are not touched. (Currently, index operations associated with
* the commands that use this are WAL-logged and so do not need fsync.
* That behavior might change someday, but in any case it's likely that
* any fsync decisions required would be per-index and hence not appropriate
* to be done here.)
*/
void
heap_sync(Relation rel)
{
/* temp tables never need fsync */
if (rel->rd_istemp)
return;
/* main heap */
FlushRelationBuffers(rel);
/* FlushRelationBuffers will have opened rd_smgr */
smgrimmedsync(rel->rd_smgr);
/* toast heap, if any */
if (OidIsValid(rel->rd_rel->reltoastrelid))
{
Relation toastrel;
toastrel = heap_open(rel->rd_rel->reltoastrelid, AccessShareLock);
FlushRelationBuffers(toastrel);
smgrimmedsync(toastrel->rd_smgr);
heap_close(toastrel, AccessShareLock);
}
}
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