Datum
rtgetmulti(PG_FUNCTION_ARGS)
{
IndexScanDesc s = (IndexScanDesc) PG_GETARG_POINTER(0);
ItemPointer tids = (ItemPointer) PG_GETARG_POINTER(1);
int32 max_tids = PG_GETARG_INT32(2);
int32 *returned_tids = (int32 *) PG_GETARG_POINTER(3);
RTreeScanOpaque so = (RTreeScanOpaque) s->opaque;
bool res = true;
int32 ntids = 0;
/* XXX generic implementation: loop around guts of rtgettuple */
while (ntids < max_tids)
{
res = rtnext(s, ForwardScanDirection);
if (res && s->ignore_killed_tuples)
{
Page page;
OffsetNumber offnum;
offnum = ItemPointerGetOffsetNumber(&(s->currentItemData));
page = BufferGetPage(so->curbuf);
if (ItemIdDeleted(PageGetItemId(page, offnum)))
continue;
}
if (!res)
break;
tids[ntids] = s->xs_ctup.t_self;
ntids++;
}
*returned_tids = ntids;
PG_RETURN_BOOL(res);
}
/*
* MUST BE CALLED ONLY ON RECOVERY.
*
* Check if exists valid (inserted by not aborted xaction) heap tuple
* for given item pointer
*/
bool
XLogIsValidTuple(RelFileNode hnode, ItemPointer iptr)
{
Relation reln;
Buffer buffer;
Page page;
ItemId lp;
HeapTupleHeader htup;
reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
if (!RelationIsValid(reln))
return (false);
buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
if (!BufferIsValid(buffer))
return (false);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew((PageHeader) page) ||
ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
{
UnlockAndReleaseBuffer(buffer);
return (false);
}
if (PageGetSUI(page) != ThisStartUpID)
{
Assert(PageGetSUI(page) < ThisStartUpID);
UnlockAndReleaseBuffer(buffer);
return (true);
}
lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
{
UnlockAndReleaseBuffer(buffer);
return (false);
}
htup = (HeapTupleHeader) PageGetItem(page, lp);
/* MUST CHECK WASN'T TUPLE INSERTED IN PREV STARTUP */
if (!(htup->t_infomask & HEAP_XMIN_COMMITTED))
{
if (htup->t_infomask & HEAP_XMIN_INVALID ||
(htup->t_infomask & HEAP_MOVED_IN &&
TransactionIdDidAbort(HeapTupleHeaderGetXvac(htup))) ||
TransactionIdDidAbort(HeapTupleHeaderGetXmin(htup)))
{
UnlockAndReleaseBuffer(buffer);
return (false);
}
}
UnlockAndReleaseBuffer(buffer);
return (true);
}
/*
* Check if specified heap tuple was inserted by given
* xaction/command and return
*
* - -1 if not
* - 0 if there is no tuple at all
* - 1 if yes
*/
int
XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr,
TransactionId xid, CommandId cid)
{
Relation reln;
Buffer buffer;
Page page;
ItemId lp;
HeapTupleHeader htup;
reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
if (!RelationIsValid(reln))
return (0);
buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
if (!BufferIsValid(buffer))
return (0);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew((PageHeader) page) ||
ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
{
UnlockAndReleaseBuffer(buffer);
return (0);
}
lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
{
UnlockAndReleaseBuffer(buffer);
return (0);
}
htup = (HeapTupleHeader) PageGetItem(page, lp);
Assert(PageGetSUI(page) == ThisStartUpID);
if (!TransactionIdEquals(HeapTupleHeaderGetXmin(htup), xid) ||
HeapTupleHeaderGetCmin(htup) != cid)
{
UnlockAndReleaseBuffer(buffer);
return (-1);
}
UnlockAndReleaseBuffer(buffer);
return (1);
}
static text *
istatus_text(ItemId itemid)
{
StringInfoData buf;
initStringInfo(&buf);
if (ItemIdDeleted(itemid))
appendStringInfoString(&buf, "DELETED ");
if (ItemIdIsNormal(itemid))
appendStringInfoString(&buf, "USED ");
if (ItemIdIsDead(itemid))
appendStringInfoString(&buf, "DEAD ");
if (buf.len == 0)
appendStringInfoString(&buf, "UNUSED ");
buf.data[buf.len - 1] = '\0';
return cstring_to_text(buf.data);
}
Datum
rtgettuple(PG_FUNCTION_ARGS)
{
IndexScanDesc s = (IndexScanDesc) PG_GETARG_POINTER(0);
ScanDirection dir = (ScanDirection) PG_GETARG_INT32(1);
RTreeScanOpaque so = (RTreeScanOpaque) s->opaque;
Page page;
OffsetNumber offnum;
/*
* If we've already produced a tuple and the executor has informed us that
* it should be marked "killed", do so now.
*/
if (s->kill_prior_tuple && ItemPointerIsValid(&(s->currentItemData)))
{
offnum = ItemPointerGetOffsetNumber(&(s->currentItemData));
page = BufferGetPage(so->curbuf);
PageGetItemId(page, offnum)->lp_flags |= LP_DELETE;
SetBufferCommitInfoNeedsSave(so->curbuf);
}
/*
* Get the next tuple that matches the search key; if asked to skip killed
* tuples, find the first non-killed tuple that matches. Return as soon as
* we've run out of matches or we've found an acceptable match.
*/
for (;;)
{
bool res = rtnext(s, dir);
if (res && s->ignore_killed_tuples)
{
offnum = ItemPointerGetOffsetNumber(&(s->currentItemData));
page = BufferGetPage(so->curbuf);
if (ItemIdDeleted(PageGetItemId(page, offnum)))
continue;
}
PG_RETURN_BOOL(res);
}
}
/* -------------------------------------------------
* GetBTPageStatistics()
*
* Collect statistics of single b-tree leaf page
* -------------------------------------------------
*/
static bool
GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat * stat)
{
Page page = BufferGetPage(buffer);
PageHeader phdr = (PageHeader) page;
OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
int item_size = 0;
int off;
stat->blkno = blkno;
stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
stat->dead_items = stat->live_items = 0;
stat->page_size = PageGetPageSize(page);
/* page type (flags) */
if (P_ISDELETED(opaque))
{
stat->type = 'd';
return true;
}
else if (P_IGNORE(opaque))
stat->type = 'e';
else if (P_ISLEAF(opaque))
stat->type = 'l';
else if (P_ISROOT(opaque))
stat->type = 'r';
else
stat->type = 'i';
/* btpage opaque data */
stat->btpo_prev = opaque->btpo_prev;
stat->btpo_next = opaque->btpo_next;
if (P_ISDELETED(opaque))
stat->btpo.xact = opaque->btpo.xact;
else
stat->btpo.level = opaque->btpo.level;
stat->btpo_flags = opaque->btpo_flags;
stat->btpo_cycleid = opaque->btpo_cycleid;
/*----------------------------------------------
* If a next leaf is on the previous block,
* it means a fragmentation.
*----------------------------------------------
*/
stat->fragments = 0;
if (stat->type == 'l')
{
if (opaque->btpo_next != P_NONE && opaque->btpo_next < blkno)
stat->fragments++;
}
/* count live and dead tuples, and free space */
for (off = FirstOffsetNumber; off <= maxoff; off++)
{
IndexTuple itup;
ItemId id = PageGetItemId(page, off);
itup = (IndexTuple) PageGetItem(page, id);
item_size += IndexTupleSize(itup);
if (!ItemIdDeleted(id))
stat->live_items++;
else
stat->dead_items++;
}
stat->free_size = PageGetFreeSpace(page);
if ((stat->live_items + stat->dead_items) > 0)
stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
else
stat->avg_item_size = 0;
return true;
}
/*
* Test whether an indextuple satisfies all the scankey conditions.
*
* If so, copy its TID into scan->xs_ctup.t_self, and return TRUE.
* If not, return FALSE (xs_ctup is not changed).
*
* If the tuple fails to pass the qual, we also determine whether there's
* any need to continue the scan beyond this tuple, and set *continuescan
* accordingly. See comments for _bt_preprocess_keys(), above, about how
* this is done.
*
* scan: index scan descriptor (containing a search-type scankey)
* page: buffer page containing index tuple
* offnum: offset number of index tuple (must be a valid item!)
* dir: direction we are scanning in
* continuescan: output parameter (will be set correctly in all cases)
*/
bool
_bt_checkkeys(IndexScanDesc scan,
Page page, OffsetNumber offnum,
ScanDirection dir, bool *continuescan)
{
ItemId iid = PageGetItemId(page, offnum);
bool tuple_valid;
IndexTuple tuple;
TupleDesc tupdesc;
BTScanOpaque so;
int keysz;
int ikey;
ScanKey key;
*continuescan = true; /* default assumption */
/*
* If the scan specifies not to return killed tuples, then we treat a
* killed tuple as not passing the qual. Most of the time, it's a win to
* not bother examining the tuple's index keys, but just return
* immediately with continuescan = true to proceed to the next tuple.
* However, if this is the last tuple on the page, we should check the
* index keys to prevent uselessly advancing to the next page.
*/
if (scan->ignore_killed_tuples && ItemIdDeleted(iid))
{
/* return immediately if there are more tuples on the page */
if (ScanDirectionIsForward(dir))
{
if (offnum < PageGetMaxOffsetNumber(page))
return false;
}
else
{
BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (offnum > P_FIRSTDATAKEY(opaque))
return false;
}
/*
* OK, we want to check the keys, but we'll return FALSE even if the
* tuple passes the key tests.
*/
tuple_valid = false;
}
else
tuple_valid = true;
tuple = (IndexTuple) PageGetItem(page, iid);
IncrIndexProcessed();
tupdesc = RelationGetDescr(scan->indexRelation);
so = (BTScanOpaque) scan->opaque;
keysz = so->numberOfKeys;
for (key = so->keyData, ikey = 0; ikey < keysz; key++, ikey++)
{
Datum datum;
bool isNull;
Datum test;
/* row-comparison keys need special processing */
if (key->sk_flags & SK_ROW_HEADER)
{
if (_bt_check_rowcompare(key, tuple, tupdesc, dir, continuescan))
continue;
return false;
}
datum = index_getattr(tuple,
key->sk_attno,
tupdesc,
&isNull);
/* btree doesn't support 'A is null' clauses, yet */
if (key->sk_flags & SK_ISNULL)
{
/* we shouldn't get here, really; see _bt_preprocess_keys() */
*continuescan = false;
return false;
}
if (isNull)
{
if (key->sk_flags & SK_BT_NULLS_FIRST)
{
/*
* Since NULLs are sorted before non-NULLs, we know we have
* reached the lower limit of the range of values for this
* index attr. On a backward scan, we can stop if this qual is
* one of the "must match" subset. On a forward scan,
* however, we should keep going.
*/
if ((key->sk_flags & SK_BT_REQBKWD) &&
ScanDirectionIsBackward(dir))
*continuescan = false;
}
else
{
/*
* Since NULLs are sorted after non-NULLs, we know we have
* reached the upper limit of the range of values for this
* index attr. On a forward scan, we can stop if this qual is
* one of the "must match" subset. On a backward scan,
* however, we should keep going.
*/
if ((key->sk_flags & SK_BT_REQFWD) &&
ScanDirectionIsForward(dir))
*continuescan = false;
}
/*
* In any case, this indextuple doesn't match the qual.
*/
return false;
}
test = FunctionCall2(&key->sk_func, datum, key->sk_argument);
if (!DatumGetBool(test))
{
/*
* Tuple fails this qual. If it's a required qual for the current
* scan direction, then we can conclude no further tuples will
* pass, either.
*
* Note: because we stop the scan as soon as any required equality
* qual fails, it is critical that equality quals be used for the
* initial positioning in _bt_first() when they are available. See
* comments in _bt_first().
*/
if ((key->sk_flags & SK_BT_REQFWD) &&
ScanDirectionIsForward(dir))
*continuescan = false;
else if ((key->sk_flags & SK_BT_REQBKWD) &&
ScanDirectionIsBackward(dir))
*continuescan = false;
/*
* In any case, this indextuple doesn't match the qual.
*/
return false;
}
}
/* If we get here, the tuple passes all index quals. */
if (tuple_valid)
scan->xs_ctup.t_self = tuple->t_tid;
return tuple_valid;
}
/*
* hashgetmulti() -- get multiple tuples at once
*
* This is a somewhat generic implementation: it avoids lock reacquisition
* overhead, but there's no smarts about picking especially good stopping
* points such as index page boundaries.
*/
Datum
hashgetmulti(PG_FUNCTION_ARGS)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
ItemPointer tids = (ItemPointer) PG_GETARG_POINTER(1);
int32 max_tids = PG_GETARG_INT32(2);
int32 *returned_tids = (int32 *) PG_GETARG_POINTER(3);
HashScanOpaque so = (HashScanOpaque) scan->opaque;
Relation rel = scan->indexRelation;
bool res = true;
int32 ntids = 0;
/*
* We hold pin but not lock on current buffer while outside the hash AM.
* Reacquire the read lock here.
*/
if (BufferIsValid(so->hashso_curbuf))
_hash_chgbufaccess(rel, so->hashso_curbuf, HASH_NOLOCK, HASH_READ);
while (ntids < max_tids)
{
/*
* Start scan, or advance to next tuple.
*/
if (ItemPointerIsValid(&(scan->currentItemData)))
res = _hash_next(scan, ForwardScanDirection);
else
res = _hash_first(scan, ForwardScanDirection);
/*
* Skip killed tuples if asked to.
*/
if (scan->ignore_killed_tuples)
{
while (res)
{
Page page;
OffsetNumber offnum;
offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
page = BufferGetPage(so->hashso_curbuf);
if (!ItemIdDeleted(PageGetItemId(page, offnum)))
break;
res = _hash_next(scan, ForwardScanDirection);
}
}
if (!res)
break;
/* Save tuple ID, and continue scanning */
tids[ntids] = scan->xs_ctup.t_self;
ntids++;
}
/* Release read lock on current buffer, but keep it pinned */
if (BufferIsValid(so->hashso_curbuf))
_hash_chgbufaccess(rel, so->hashso_curbuf, HASH_READ, HASH_NOLOCK);
*returned_tids = ntids;
PG_RETURN_BOOL(res);
}
/*
* hashgettuple() -- Get the next tuple in the scan.
*/
Datum
hashgettuple(PG_FUNCTION_ARGS)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
ScanDirection dir = (ScanDirection) PG_GETARG_INT32(1);
HashScanOpaque so = (HashScanOpaque) scan->opaque;
Relation rel = scan->indexRelation;
Page page;
OffsetNumber offnum;
bool res;
/*
* We hold pin but not lock on current buffer while outside the hash AM.
* Reacquire the read lock here.
*/
if (BufferIsValid(so->hashso_curbuf))
_hash_chgbufaccess(rel, so->hashso_curbuf, HASH_NOLOCK, HASH_READ);
/*
* If we've already initialized this scan, we can just advance it in the
* appropriate direction. If we haven't done so yet, we call a routine to
* get the first item in the scan.
*/
if (ItemPointerIsValid(&(scan->currentItemData)))
{
/*
* Check to see if we should kill the previously-fetched tuple.
*/
if (scan->kill_prior_tuple)
{
/*
* Yes, so mark it by setting the LP_DELETE bit in the item flags.
*/
offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
page = BufferGetPage(so->hashso_curbuf);
PageGetItemId(page, offnum)->lp_flags |= LP_DELETE;
/*
* Since this can be redone later if needed, it's treated the same
* as a commit-hint-bit status update for heap tuples: we mark the
* buffer dirty but don't make a WAL log entry.
*/
SetBufferCommitInfoNeedsSave(so->hashso_curbuf);
}
/*
* Now continue the scan.
*/
res = _hash_next(scan, dir);
}
else
res = _hash_first(scan, dir);
/*
* Skip killed tuples if asked to.
*/
if (scan->ignore_killed_tuples)
{
while (res)
{
offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
page = BufferGetPage(so->hashso_curbuf);
if (!ItemIdDeleted(PageGetItemId(page, offnum)))
break;
res = _hash_next(scan, dir);
}
}
/* Release read lock on current buffer, but keep it pinned */
if (BufferIsValid(so->hashso_curbuf))
_hash_chgbufaccess(rel, so->hashso_curbuf, HASH_READ, HASH_NOLOCK);
PG_RETURN_BOOL(res);
}
/*
* PageRepairFragmentation
*
* Frees fragmented space on a page.
* It doesn't remove unused line pointers! Please don't change this.
*
* This routine is usable for heap pages only, but see PageIndexMultiDelete.
*
* Returns number of unused line pointers on page. If "unused" is not NULL
* then the unused[] array is filled with indexes of unused line pointers.
*/
int
PageRepairFragmentation(Page page, OffsetNumber *unused)
{
Offset pd_lower = ((PageHeader) page)->pd_lower;
Offset pd_upper = ((PageHeader) page)->pd_upper;
Offset pd_special = ((PageHeader) page)->pd_special;
itemIdSort itemidbase,
itemidptr;
ItemId lp;
int nline,
nused;
int i;
Size totallen;
Offset upper;
/*
* It's worth the trouble to be more paranoid here than in most places,
* because we are about to reshuffle data in (what is usually) a shared
* disk buffer. If we aren't careful then corrupted pointers, lengths,
* etc could cause us to clobber adjacent disk buffers, spreading the data
* loss further. So, check everything.
*/
if (pd_lower < SizeOfPageHeaderData ||
pd_lower > pd_upper ||
pd_upper > pd_special ||
pd_special > BLCKSZ ||
pd_special != MAXALIGN(pd_special))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
pd_lower, pd_upper, pd_special),
errSendAlert(true)));
nline = PageGetMaxOffsetNumber(page);
nused = 0;
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
if (ItemIdDeleted(lp)) /* marked for deletion */
lp->lp_flags &= ~(LP_USED | LP_DELETE);
if (ItemIdIsUsed(lp))
nused++;
else if (unused)
unused[i - nused] = (OffsetNumber) i;
}
if (nused == 0)
{
/* Page is completely empty, so just reset it quickly */
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
lp->lp_len = 0; /* indicate unused & deallocated */
}
((PageHeader) page)->pd_upper = pd_special;
}
else
{ /* nused != 0 */
/* Need to compact the page the hard way */
itemidbase = (itemIdSort) palloc(sizeof(itemIdSortData) * nused);
itemidptr = itemidbase;
totallen = 0;
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
if (ItemIdIsUsed(lp))
{
itemidptr->offsetindex = i;
itemidptr->itemoff = ItemIdGetOffset(lp);
if (itemidptr->itemoff < (int) pd_upper ||
itemidptr->itemoff >= (int) pd_special)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item pointer: %u",
itemidptr->itemoff),
errSendAlert(true)));
itemidptr->alignedlen = MAXALIGN(ItemIdGetLength(lp));
totallen += itemidptr->alignedlen;
itemidptr++;
}
else
{
lp->lp_len = 0; /* indicate unused & deallocated */
}
}
if (totallen > (Size) (pd_special - pd_lower))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item lengths: total %u, available space %u",
(unsigned int) totallen, pd_special - pd_lower),
errSendAlert(true)));
/* sort itemIdSortData array into decreasing itemoff order */
qsort((char *) itemidbase, nused, sizeof(itemIdSortData),
itemoffcompare);
/* compactify page */
upper = pd_special;
for (i = 0, itemidptr = itemidbase; i < nused; i++, itemidptr++)
{
lp = PageGetItemId(page, itemidptr->offsetindex + 1);
upper -= itemidptr->alignedlen;
memmove((char *) page + upper,
(char *) page + itemidptr->itemoff,
itemidptr->alignedlen);
lp->lp_off = upper;
}
((PageHeader) page)->pd_upper = upper;
pfree(itemidbase);
}
/* Set hint bit for PageAddItem */
if (nused < nline)
PageSetHasFreeLinePointers(page);
else
PageClearHasFreeLinePointers(page);
return (nline - nused);
}
