/*
* Decide whether a cached PLyProcedure struct is still valid
*/
static bool
PLy_procedure_valid(PLyProcedure *proc, HeapTuple procTup)
{
int i;
bool valid;
Assert(proc != NULL);
/* If the pg_proc tuple has changed, it's not valid */
if (!(proc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
ItemPointerEquals(&proc->fn_tid, &procTup->t_self)))
return false;
/* Else check the input argument datatypes */
valid = true;
for (i = 0; i < proc->nargs; i++)
{
valid = PLy_procedure_argument_valid(&proc->args[i]);
/* Short-circuit on first changed argument */
if (!valid)
break;
}
/* if the output type is composite, it might have changed */
if (valid)
valid = PLy_procedure_argument_valid(&proc->result);
return valid;
}
/*
* Check if our cached information about a datatype is still valid
*/
static bool
PLy_procedure_argument_valid(PLyTypeInfo *arg)
{
HeapTuple relTup;
bool valid;
/* Nothing to cache unless type is composite */
if (arg->is_rowtype != 1)
return true;
/*
* Zero typ_relid means that we got called on an output argument of a
* function returning a unnamed record type; the info for it can't change.
*/
if (!OidIsValid(arg->typ_relid))
return true;
/* Else we should have some cached data */
Assert(TransactionIdIsValid(arg->typrel_xmin));
Assert(ItemPointerIsValid(&arg->typrel_tid));
/* Get the pg_class tuple for the data type */
relTup = SearchSysCache1(RELOID, ObjectIdGetDatum(arg->typ_relid));
if (!HeapTupleIsValid(relTup))
elog(ERROR, "cache lookup failed for relation %u", arg->typ_relid);
/* If it has changed, the cached data is not valid */
valid = (arg->typrel_xmin == HeapTupleHeaderGetXmin(relTup->t_data) &&
ItemPointerEquals(&arg->typrel_tid, &relTup->t_self));
ReleaseSysCache(relTup);
return valid;
}
/*
* 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);
}
/*
* This function performs checks for certain system tables to validate tuple
* fetched from table has the key, using which it was fetched from index.
*/
static void
CrossCheckTuple(int cacheId,
Datum key1,
Datum key2,
Datum key3,
Datum key4,
HeapTuple tuple)
{
Form_pg_class rd_rel;
switch (cacheId)
{
case RELOID:
if (HeapTupleGetOid(tuple) != DatumGetObjectId(key1))
{
elog(ERROR, "pg_class_oid_index is broken, oid=%d is pointing to tuple with oid=%d (xmin:%u xmax:%u)",
DatumGetObjectId(key1), HeapTupleGetOid(tuple),
HeapTupleHeaderGetXmin((tuple)->t_data),
HeapTupleHeaderGetXmax((tuple)->t_data));
}
break;
case RELNAMENSP:
rd_rel = (Form_pg_class) GETSTRUCT(tuple);
if (strncmp(rd_rel->relname.data, DatumGetCString(key1), NAMEDATALEN) != 0)
{
elog(ERROR, "pg_class_relname_nsp_index is broken, intended tuple with name \"%s\" fetched \"%s\""
" (xmin:%u xmax:%u)",
DatumGetCString(key1), rd_rel->relname.data,
HeapTupleHeaderGetXmin((tuple)->t_data),
HeapTupleHeaderGetXmax((tuple)->t_data));
}
break;
case TYPEOID:
if (HeapTupleGetOid(tuple) != DatumGetObjectId(key1))
{
elog(ERROR, "pg_type_oid_index is broken, oid=%d is pointing to tuple with oid=%d (xmin:%u xmax:%u)",
DatumGetObjectId(key1), HeapTupleGetOid(tuple),
HeapTupleHeaderGetXmin((tuple)->t_data),
HeapTupleHeaderGetXmax((tuple)->t_data));
}
break;
}
}
/* ----------------
* heap_getsysattr
*
* Fetch the value of a system attribute for a tuple.
*
* This is a support routine for the heap_getattr macro. The macro
* has already determined that the attnum refers to a system attribute.
* ----------------
*/
Datum
heap_getsysattr(HeapTuple tup, int attnum, bool *isnull)
{
Datum result;
Assert(tup);
Assert(!is_heaptuple_memtuple(tup));
/* Currently, no sys attribute ever reads as NULL. */
if (isnull)
*isnull = false;
switch (attnum)
{
case SelfItemPointerAttributeNumber:
/* pass-by-reference datatype */
result = PointerGetDatum(&(tup->t_self));
break;
case ObjectIdAttributeNumber:
result = ObjectIdGetDatum(HeapTupleGetOid(tup));
break;
case MinTransactionIdAttributeNumber:
result = TransactionIdGetDatum(HeapTupleHeaderGetXmin(tup->t_data));
break;
case MaxTransactionIdAttributeNumber:
result = TransactionIdGetDatum(HeapTupleHeaderGetXmax(tup->t_data));
break;
case MinCommandIdAttributeNumber:
case MaxCommandIdAttributeNumber:
/*
* cmin and cmax are now both aliases for the same field, which
* can in fact also be a combo command id. XXX perhaps we should
* return the "real" cmin or cmax if possible, that is if we are
* inside the originating transaction?
*/
result = CommandIdGetDatum(HeapTupleHeaderGetRawCommandId(tup->t_data));
break;
case TableOidAttributeNumber:
/* CDB: Must now use a TupleTableSlot to access the 'tableoid'. */
result = ObjectIdGetDatum(InvalidOid);
elog(ERROR, "Invalid reference to \"tableoid\" system attribute");
break;
case GpSegmentIdAttributeNumber: /*CDB*/
result = Int32GetDatum(Gp_segment);
break;
default:
elog(ERROR, "invalid attnum: %d", attnum);
result = 0; /* keep compiler quiet */
break;
}
return result;
}
CommandId
HeapTupleHeaderGetCmin(HeapTupleHeader tup)
{
CommandId cid = HeapTupleHeaderGetRawCommandId(tup);
Assert(!(tup->t_infomask & HEAP_MOVED));
if (tup->t_infomask & HEAP_COMBOCID)
return GetRealCmin(HeapTupleHeaderGetXmin(tup), cid);
else
return cid;
}
/*
* Given a tuple we are about to delete, determine the correct value to store
* into its t_cid field.
*
* If we don't need a combo CID, *cmax is unchanged and *iscombo is set to
* FALSE. If we do need one, *cmax is replaced by a combo CID and *iscombo
* is set to TRUE.
*
* The reason this is separate from the actual HeapTupleHeaderSetCmax()
* operation is that this could fail due to out-of-memory conditions. Hence
* we need to do this before entering the critical section that actually
* changes the tuple in shared buffers.
*/
void
HeapTupleHeaderAdjustCmax(HeapTupleHeader tup,
CommandId *cmax,
bool *iscombo)
{
/*
* If we're marking a tuple deleted that was inserted by (any
* subtransaction of) our transaction, we need to use a combo command id.
* Test for HEAP_XMIN_COMMITTED first, because it's cheaper than a
* TransactionIdIsCurrentTransactionId call.
*/
if (!(tup->t_infomask & HEAP_XMIN_COMMITTED) &&
TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tup)))
{
CommandId cmin = HeapTupleHeaderGetRawCommandId(tup);
*cmax = GetComboCommandId(HeapTupleHeaderGetXmin(tup), cmin, *cmax);
*iscombo = true;
}
else
{
*iscombo = false;
}
}
/*
* 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);
}
CommandId
HeapTupleHeaderGetCmax(HeapTupleHeader tup)
{
CommandId cid = HeapTupleHeaderGetRawCommandId(tup);
/* We do not store cmax when locking a tuple */
Assert(!(tup->t_infomask & (HEAP_MOVED | HEAP_IS_LOCKED)));
/*
* MPP-8317: cursors can't always *tell* that this is the current transaction.
*/
Assert(QEDtxContextInfo.cursorContext || TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tup)));
if (tup->t_infomask & HEAP_COMBOCID)
return GetRealCmax(HeapTupleHeaderGetXmin(tup), cid);
else
return cid;
}
/*
* Register a dead tuple with an ongoing rewrite. Dead tuples are not
* copied to the new table, but we still make note of them so that we
* can release some resources earlier.
*
* Returns true if a tuple was removed from the unresolved_tups table.
* This indicates that that tuple, previously thought to be "recently dead",
* is now known really dead and won't be written to the output.
*/
bool
rewrite_heap_dead_tuple(RewriteState state, HeapTuple old_tuple)
{
/*
* If we have already seen an earlier tuple in the update chain that
* points to this tuple, let's forget about that earlier tuple. It's in
* fact dead as well, our simple xmax < OldestXmin test in
* HeapTupleSatisfiesVacuum just wasn't enough to detect it. It happens
* when xmin of a tuple is greater than xmax, which sounds
* counter-intuitive but is perfectly valid.
*
* We don't bother to try to detect the situation the other way round,
* when we encounter the dead tuple first and then the recently dead one
* that points to it. If that happens, we'll have some unmatched entries
* in the UnresolvedTups hash table at the end. That can happen anyway,
* because a vacuum might have removed the dead tuple in the chain before
* us.
*/
UnresolvedTup unresolved;
TidHashKey hashkey;
bool found;
memset(&hashkey, 0, sizeof(hashkey));
hashkey.xmin = HeapTupleHeaderGetXmin(old_tuple->t_data);
hashkey.tid = old_tuple->t_self;
unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
HASH_FIND, NULL);
if (unresolved != NULL)
{
/* Need to free the contained tuple as well as the hashtable entry */
heap_freetuple(unresolved->tuple);
hash_search(state->rs_unresolved_tups, &hashkey,
HASH_REMOVE, &found);
Assert(found);
return true;
}
return false;
}
/*
* PyPgFunction_IsCurrent - determine if the current pg_proc entry is newer than 'func'
*/
bool
PyPgFunction_IsCurrent(PyObj func)
{
HeapTuple ht;
ItemPointerData fn_tid;
TransactionId fn_xmin, last_fn_xmin;
last_fn_xmin = PyPgFunction_GetXMin(func);
if (last_fn_xmin == InvalidTransactionId)
{
/* pseudo-function */
return(true);
}
ht = SearchSysCache(PROCOID, PyPgFunction_GetOid(func), 0, 0, 0);
if (!HeapTupleIsValid(ht))
return(false);
fn_xmin = HeapTupleHeaderGetXmin(ht->t_data);
fn_tid = ht->t_self;
ReleaseSysCache(ht);
if (last_fn_xmin != fn_xmin ||
!ItemPointerEquals(PyPgFunction_GetItemPointer(func), &fn_tid))
{
return(false);
}
if (!PyPgTupleDesc_IsCurrent(PyPgFunction_GetInput(func)))
{
return(false);
}
if (!PyPgType_IsCurrent(PyPgFunction_GetOutput(func)))
return(false);
return(true);
}
/*
* Check whether a tuple is all-visible relative to a given OldestXmin value.
* The buffer should contain the tuple and should be locked and pinned.
*/
static bool
tuple_all_visible(HeapTuple tup, TransactionId OldestXmin, Buffer buffer)
{
HTSV_Result state;
TransactionId xmin;
state = HeapTupleSatisfiesVacuum(tup, OldestXmin, buffer);
if (state != HEAPTUPLE_LIVE)
return false; /* all-visible implies live */
/*
* Neither lazy_scan_heap nor heap_page_is_all_visible will mark a page
* all-visible unless every tuple is hinted committed. However, those hint
* bits could be lost after a crash, so we can't be certain that they'll
* be set here. So just check the xmin.
*/
xmin = HeapTupleHeaderGetXmin(tup->t_data);
if (!TransactionIdPrecedes(xmin, OldestXmin))
return false; /* xmin not old enough for all to see */
return true;
}
/*
* HeapTupleSatisfiesItself
* True iff heap tuple is valid "for itself".
*
* Here, we consider the effects of:
* all committed transactions (as of the current instant)
* previous commands of this transaction
* changes made by the current command
*
* Note:
* Assumes heap tuple is valid.
*
* The satisfaction of "itself" requires the following:
*
* ((Xmin == my-transaction && the row was updated by the current transaction, and
* (Xmax is null it was not deleted
* [|| Xmax != my-transaction)]) [or it was deleted by another transaction]
* ||
*
* (Xmin is committed && the row was modified by a committed transaction, and
* (Xmax is null || the row has not been deleted, or
* (Xmax != my-transaction && the row was deleted by another transaction
* Xmax is not committed))) that has not been committed
*/
bool
HeapTupleSatisfiesItself(HeapTupleHeader tuple)
{
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return false;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return false;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return false;
if (TransactionIdDidCommit(xvac))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return true;
Assert(TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)));
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
return false;
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
return false;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
/* by here, the inserting transaction has committed */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return true;
if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
{
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
return false; /* updated by other */
}
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
return false;
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return true;
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMAX_INVALID;
return true;
}
/* xmax transaction committed */
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
{
tuple->t_infomask |= HEAP_XMAX_INVALID;
return true;
}
tuple->t_infomask |= HEAP_XMAX_COMMITTED;
return false;
}
/*
* Add a tuple to the new heap.
*
* Visibility information is copied from the original tuple, except that
* we "freeze" very-old tuples. Note that since we scribble on new_tuple,
* it had better be temp storage not a pointer to the original tuple.
*
* state opaque state as returned by begin_heap_rewrite
* old_tuple original tuple in the old heap
* new_tuple new, rewritten tuple to be inserted to new heap
*/
void
rewrite_heap_tuple(RewriteState state,
HeapTuple old_tuple, HeapTuple new_tuple)
{
MemoryContext old_cxt;
ItemPointerData old_tid;
TidHashKey hashkey;
bool found;
bool free_new;
old_cxt = MemoryContextSwitchTo(state->rs_cxt);
/*
* Copy the original tuple's visibility information into new_tuple.
*
* XXX we might later need to copy some t_infomask2 bits, too? Right now,
* we intentionally clear the HOT status bits.
*/
memcpy(&new_tuple->t_data->t_choice.t_heap,
&old_tuple->t_data->t_choice.t_heap,
sizeof(HeapTupleFields));
new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
new_tuple->t_data->t_infomask |=
old_tuple->t_data->t_infomask & HEAP_XACT_MASK;
/*
* While we have our hands on the tuple, we may as well freeze any
* eligible xmin or xmax, so that future VACUUM effort can be saved.
*/
heap_freeze_tuple(new_tuple->t_data, state->rs_freeze_xid,
state->rs_cutoff_multi);
/*
* Invalid ctid means that ctid should point to the tuple itself. We'll
* override it later if the tuple is part of an update chain.
*/
ItemPointerSetInvalid(&new_tuple->t_data->t_ctid);
/*
* If the tuple has been updated, check the old-to-new mapping hash table.
*/
if (!((old_tuple->t_data->t_infomask & HEAP_XMAX_INVALID) ||
HeapTupleHeaderIsOnlyLocked(old_tuple->t_data)) &&
!(ItemPointerEquals(&(old_tuple->t_self),
&(old_tuple->t_data->t_ctid))))
{
OldToNewMapping mapping;
memset(&hashkey, 0, sizeof(hashkey));
hashkey.xmin = HeapTupleHeaderGetUpdateXid(old_tuple->t_data);
hashkey.tid = old_tuple->t_data->t_ctid;
mapping = (OldToNewMapping)
hash_search(state->rs_old_new_tid_map, &hashkey,
HASH_FIND, NULL);
if (mapping != NULL)
{
/*
* We've already copied the tuple that t_ctid points to, so we can
* set the ctid of this tuple to point to the new location, and
* insert it right away.
*/
new_tuple->t_data->t_ctid = mapping->new_tid;
/* We don't need the mapping entry anymore */
hash_search(state->rs_old_new_tid_map, &hashkey,
HASH_REMOVE, &found);
Assert(found);
}
else
{
/*
* We haven't seen the tuple t_ctid points to yet. Stash this
* tuple into unresolved_tups to be written later.
*/
UnresolvedTup unresolved;
unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
HASH_ENTER, &found);
Assert(!found);
unresolved->old_tid = old_tuple->t_self;
unresolved->tuple = heap_copytuple(new_tuple);
/*
* We can't do anything more now, since we don't know where the
* tuple will be written.
*/
MemoryContextSwitchTo(old_cxt);
return;
}
}
/*
* Now we will write the tuple, and then check to see if it is the B tuple
* in any new or known pair. When we resolve a known pair, we will be
* able to write that pair's A tuple, and then we have to check if it
* resolves some other pair. Hence, we need a loop here.
*/
old_tid = old_tuple->t_self;
free_new = false;
for (;;)
{
ItemPointerData new_tid;
/* Insert the tuple and find out where it's put in new_heap */
raw_heap_insert(state, new_tuple);
new_tid = new_tuple->t_self;
/*
* If the tuple is the updated version of a row, and the prior version
* wouldn't be DEAD yet, then we need to either resolve the prior
* version (if it's waiting in rs_unresolved_tups), or make an entry
* in rs_old_new_tid_map (so we can resolve it when we do see it). The
* previous tuple's xmax would equal this one's xmin, so it's
* RECENTLY_DEAD if and only if the xmin is not before OldestXmin.
*/
if ((new_tuple->t_data->t_infomask & HEAP_UPDATED) &&
!TransactionIdPrecedes(HeapTupleHeaderGetXmin(new_tuple->t_data),
state->rs_oldest_xmin))
{
/*
* Okay, this is B in an update pair. See if we've seen A.
*/
UnresolvedTup unresolved;
memset(&hashkey, 0, sizeof(hashkey));
hashkey.xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
hashkey.tid = old_tid;
unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
HASH_FIND, NULL);
if (unresolved != NULL)
{
/*
* We have seen and memorized the previous tuple already. Now
* that we know where we inserted the tuple its t_ctid points
* to, fix its t_ctid and insert it to the new heap.
*/
if (free_new)
heap_freetuple(new_tuple);
new_tuple = unresolved->tuple;
free_new = true;
old_tid = unresolved->old_tid;
new_tuple->t_data->t_ctid = new_tid;
/*
* We don't need the hash entry anymore, but don't free its
* tuple just yet.
*/
hash_search(state->rs_unresolved_tups, &hashkey,
HASH_REMOVE, &found);
Assert(found);
/* loop back to insert the previous tuple in the chain */
continue;
}
else
{
/*
* Remember the new tid of this tuple. We'll use it to set the
* ctid when we find the previous tuple in the chain.
*/
OldToNewMapping mapping;
mapping = hash_search(state->rs_old_new_tid_map, &hashkey,
HASH_ENTER, &found);
Assert(!found);
mapping->new_tid = new_tid;
}
}
/* Done with this (chain of) tuples, for now */
if (free_new)
heap_freetuple(new_tuple);
break;
}
MemoryContextSwitchTo(old_cxt);
}
/*
* See the comments for HeapTupleSatisfiesMVCC for the semantics this function
* obeys.
*
* Only usable on tuples from catalog tables!
*
* We don't need to support HEAP_MOVED_(IN|OFF) for now because we only support
* reading catalog pages which couldn't have been created in an older version.
*
* We don't set any hint bits in here as it seems unlikely to be beneficial as
* those should already be set by normal access and it seems to be too
* dangerous to do so as the semantics of doing so during timetravel are more
* complicated than when dealing "only" with the present.
*/
bool
HeapTupleSatisfiesHistoricMVCC(HeapTuple htup, Snapshot snapshot,
Buffer buffer)
{
HeapTupleHeader tuple = htup->t_data;
TransactionId xmin = HeapTupleHeaderGetXmin(tuple);
TransactionId xmax = HeapTupleHeaderGetRawXmax(tuple);
Assert(ItemPointerIsValid(&htup->t_self));
Assert(htup->t_tableOid != InvalidOid);
/* inserting transaction aborted */
if (HeapTupleHeaderXminInvalid(tuple))
{
Assert(!TransactionIdDidCommit(xmin));
return false;
}
/* check if it's one of our txids, toplevel is also in there */
else if (TransactionIdInArray(xmin, snapshot->subxip, snapshot->subxcnt))
{
bool resolved;
CommandId cmin = HeapTupleHeaderGetRawCommandId(tuple);
CommandId cmax = InvalidCommandId;
/*
* another transaction might have (tried to) delete this tuple or
* cmin/cmax was stored in a combocid. So we need to lookup the actual
* values externally.
*/
resolved = ResolveCminCmaxDuringDecoding(HistoricSnapshotGetTupleCids(), snapshot,
htup, buffer,
&cmin, &cmax);
if (!resolved)
elog(ERROR, "could not resolve cmin/cmax of catalog tuple");
Assert(cmin != InvalidCommandId);
if (cmin >= snapshot->curcid)
return false; /* inserted after scan started */
/* fall through */
}
/* committed before our xmin horizon. Do a normal visibility check. */
else if (TransactionIdPrecedes(xmin, snapshot->xmin))
{
Assert(!(HeapTupleHeaderXminCommitted(tuple) &&
!TransactionIdDidCommit(xmin)));
/* check for hint bit first, consult clog afterwards */
if (!HeapTupleHeaderXminCommitted(tuple) &&
!TransactionIdDidCommit(xmin))
return false;
/* fall through */
}
/* beyond our xmax horizon, i.e. invisible */
else if (TransactionIdFollowsOrEquals(xmin, snapshot->xmax))
{
return false;
}
/* check if it's a committed transaction in [xmin, xmax) */
else if (TransactionIdInArray(xmin, snapshot->xip, snapshot->xcnt))
{
/* fall through */
}
/*
* none of the above, i.e. between [xmin, xmax) but hasn't committed. I.e.
* invisible.
*/
else
{
return false;
}
/* at this point we know xmin is visible, go on to check xmax */
/* xid invalid or aborted */
if (tuple->t_infomask & HEAP_XMAX_INVALID)
return true;
/* locked tuples are always visible */
else if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask))
return true;
/*
* We can see multis here if we're looking at user tables or if somebody
* SELECT ... FOR SHARE/UPDATE a system table.
*/
else if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
xmax = HeapTupleGetUpdateXid(tuple);
}
/* check if it's one of our txids, toplevel is also in there */
if (TransactionIdInArray(xmax, snapshot->subxip, snapshot->subxcnt))
{
bool resolved;
CommandId cmin;
CommandId cmax = HeapTupleHeaderGetRawCommandId(tuple);
/* Lookup actual cmin/cmax values */
resolved = ResolveCminCmaxDuringDecoding(HistoricSnapshotGetTupleCids(), snapshot,
htup, buffer,
&cmin, &cmax);
if (!resolved)
elog(ERROR, "could not resolve combocid to cmax");
Assert(cmax != InvalidCommandId);
if (cmax >= snapshot->curcid)
return true; /* deleted after scan started */
else
return false; /* deleted before scan started */
}
/* below xmin horizon, normal transaction state is valid */
else if (TransactionIdPrecedes(xmax, snapshot->xmin))
{
Assert(!(tuple->t_infomask & HEAP_XMAX_COMMITTED &&
!TransactionIdDidCommit(xmax)));
/* check hint bit first */
if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
return false;
/* check clog */
return !TransactionIdDidCommit(xmax);
}
/* above xmax horizon, we cannot possibly see the deleting transaction */
else if (TransactionIdFollowsOrEquals(xmax, snapshot->xmax))
return true;
/* xmax is between [xmin, xmax), check known committed array */
else if (TransactionIdInArray(xmax, snapshot->xip, snapshot->xcnt))
return false;
/* xmax is between [xmin, xmax), but known not to have committed yet */
else
return true;
}
/*
* HeapTupleSatisfiesMVCC
* True iff heap tuple is valid for the given MVCC snapshot.
*
* Here, we consider the effects of:
* all transactions committed as of the time of the given snapshot
* previous commands of this transaction
*
* Does _not_ include:
* transactions shown as in-progress by the snapshot
* transactions started after the snapshot was taken
* changes made by the current command
*
* This is the same as HeapTupleSatisfiesNow, except that transactions that
* were in progress or as yet unstarted when the snapshot was taken will
* be treated as uncommitted, even if they have committed by now.
*
* (Notice, however, that the tuple status hint bits will be updated on the
* basis of the true state of the transaction, even if we then pretend we
* can't see it.)
*/
bool
HeapTupleSatisfiesMVCC(HeapTupleHeader tuple, Snapshot snapshot,
Buffer buffer)
{
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return false;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return false;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return false;
if (TransactionIdDidCommit(xvac))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
else
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (HeapTupleHeaderGetCmin(tuple) >= snapshot->curcid)
return false; /* inserted after scan started */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return true;
if (tuple->t_infomask & HEAP_IS_LOCKED) /* not deleter */
return true;
Assert(!(tuple->t_infomask & HEAP_XMAX_IS_MULTI));
if (!TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
/* deleting subtransaction must have aborted */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return true;
}
if (HeapTupleHeaderGetCmax(tuple) >= snapshot->curcid)
return true; /* deleted after scan started */
else
return false; /* deleted before scan started */
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
return false;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
HeapTupleHeaderGetXmin(tuple));
else
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
}
/*
* By here, the inserting transaction has committed - have to check
* when...
*/
if (XidInMVCCSnapshot(HeapTupleHeaderGetXmin(tuple), snapshot))
return false; /* treat as still in progress */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return true;
if (tuple->t_infomask & HEAP_IS_LOCKED)
return true;
if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
/* MultiXacts are currently only allowed to lock tuples */
Assert(tuple->t_infomask & HEAP_IS_LOCKED);
return true;
}
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (HeapTupleHeaderGetCmax(tuple) >= snapshot->curcid)
return true; /* deleted after scan started */
else
return false; /* deleted before scan started */
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return true;
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return true;
}
/* xmax transaction committed */
SetHintBits(tuple, buffer, HEAP_XMAX_COMMITTED,
HeapTupleHeaderGetXmax(tuple));
}
/*
* OK, the deleting transaction committed too ... but when?
*/
if (XidInMVCCSnapshot(HeapTupleHeaderGetXmax(tuple), snapshot))
return true; /* treat as still in progress */
return false;
}
/*
* HeapTupleSatisfiesDirty
* True iff heap tuple is valid including effects of open transactions.
*
* Here, we consider the effects of:
* all committed and in-progress transactions (as of the current instant)
* previous commands of this transaction
* changes made by the current command
*
* This is essentially like HeapTupleSatisfiesSelf as far as effects of
* the current transaction and committed/aborted xacts are concerned.
* However, we also include the effects of other xacts still in progress.
*
* A special hack is that the passed-in snapshot struct is used as an
* output argument to return the xids of concurrent xacts that affected the
* tuple. snapshot->xmin is set to the tuple's xmin if that is another
* transaction that's still in progress; or to InvalidTransactionId if the
* tuple's xmin is committed good, committed dead, or my own xact. Similarly
* for snapshot->xmax and the tuple's xmax.
*/
bool
HeapTupleSatisfiesDirty(HeapTupleHeader tuple, Snapshot snapshot,
Buffer buffer)
{
snapshot->xmin = snapshot->xmax = InvalidTransactionId;
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return false;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return false;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return false;
if (TransactionIdDidCommit(xvac))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
else
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return true;
if (tuple->t_infomask & HEAP_IS_LOCKED) /* not deleter */
return true;
Assert(!(tuple->t_infomask & HEAP_XMAX_IS_MULTI));
if (!TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
/* deleting subtransaction must have aborted */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return true;
}
return false;
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
{
snapshot->xmin = HeapTupleHeaderGetXmin(tuple);
/* XXX shouldn't we fall through to look at xmax? */
return true; /* in insertion by other */
}
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
HeapTupleHeaderGetXmin(tuple));
else
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return false;
}
}
/* by here, the inserting transaction has committed */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return true;
if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
{
if (tuple->t_infomask & HEAP_IS_LOCKED)
return true;
return false; /* updated by other */
}
if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
/* MultiXacts are currently only allowed to lock tuples */
Assert(tuple->t_infomask & HEAP_IS_LOCKED);
return true;
}
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (tuple->t_infomask & HEAP_IS_LOCKED)
return true;
return false;
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
{
snapshot->xmax = HeapTupleHeaderGetXmax(tuple);
return true;
}
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return true;
}
/* xmax transaction committed */
if (tuple->t_infomask & HEAP_IS_LOCKED)
{
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return true;
}
SetHintBits(tuple, buffer, HEAP_XMAX_COMMITTED,
HeapTupleHeaderGetXmax(tuple));
return false; /* updated by other */
}
/*
* HeapTupleSatisfiesUpdate
*
* Same logic as HeapTupleSatisfiesNow, but returns a more detailed result
* code, since UPDATE needs to know more than "is it visible?". Also,
* tuples of my own xact are tested against the passed CommandId not
* CurrentCommandId.
*
* The possible return codes are:
*
* HeapTupleInvisible: the tuple didn't exist at all when the scan started,
* e.g. it was created by a later CommandId.
*
* HeapTupleMayBeUpdated: The tuple is valid and visible, so it may be
* updated.
*
* HeapTupleSelfUpdated: The tuple was updated by the current transaction,
* after the current scan started.
*
* HeapTupleUpdated: The tuple was updated by a committed transaction.
*
* HeapTupleBeingUpdated: The tuple is being updated by an in-progress
* transaction other than the current transaction. (Note: this includes
* the case where the tuple is share-locked by a MultiXact, even if the
* MultiXact includes the current transaction. Callers that want to
* distinguish that case must test for it themselves.)
*/
HTSU_Result
HeapTupleSatisfiesUpdate(HeapTupleHeader tuple, CommandId curcid,
Buffer buffer)
{
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return HeapTupleInvisible;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return HeapTupleInvisible;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HeapTupleInvisible;
}
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return HeapTupleInvisible;
if (TransactionIdDidCommit(xvac))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
else
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HeapTupleInvisible;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (HeapTupleHeaderGetCmin(tuple) >= curcid)
return HeapTupleInvisible; /* inserted after scan started */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return HeapTupleMayBeUpdated;
if (tuple->t_infomask & HEAP_IS_LOCKED) /* not deleter */
return HeapTupleMayBeUpdated;
Assert(!(tuple->t_infomask & HEAP_XMAX_IS_MULTI));
if (!TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
/* deleting subtransaction must have aborted */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return HeapTupleMayBeUpdated;
}
if (HeapTupleHeaderGetCmax(tuple) >= curcid)
return HeapTupleSelfUpdated; /* updated after scan started */
else
return HeapTupleInvisible; /* updated before scan started */
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
return HeapTupleInvisible;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
HeapTupleHeaderGetXmin(tuple));
else
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HeapTupleInvisible;
}
}
/* by here, the inserting transaction has committed */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return HeapTupleMayBeUpdated;
if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
{
if (tuple->t_infomask & HEAP_IS_LOCKED)
return HeapTupleMayBeUpdated;
return HeapTupleUpdated; /* updated by other */
}
if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
/* MultiXacts are currently only allowed to lock tuples */
Assert(tuple->t_infomask & HEAP_IS_LOCKED);
if (MultiXactIdIsRunning(HeapTupleHeaderGetXmax(tuple)))
return HeapTupleBeingUpdated;
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return HeapTupleMayBeUpdated;
}
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (tuple->t_infomask & HEAP_IS_LOCKED)
return HeapTupleMayBeUpdated;
if (HeapTupleHeaderGetCmax(tuple) >= curcid)
return HeapTupleSelfUpdated; /* updated after scan started */
else
return HeapTupleInvisible; /* updated before scan started */
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return HeapTupleBeingUpdated;
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return HeapTupleMayBeUpdated;
}
/* xmax transaction committed */
if (tuple->t_infomask & HEAP_IS_LOCKED)
{
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return HeapTupleMayBeUpdated;
}
SetHintBits(tuple, buffer, HEAP_XMAX_COMMITTED,
HeapTupleHeaderGetXmax(tuple));
return HeapTupleUpdated; /* updated by other */
}
/*
* HeapTupleSatisfiesVacuum
*
* Determine the status of tuples for VACUUM purposes. Here, what
* we mainly want to know is if a tuple is potentially visible to *any*
* running transaction. If so, it can't be removed yet by VACUUM.
*
* OldestXmin is a cutoff XID (obtained from GetOldestXmin()). Tuples
* deleted by XIDs >= OldestXmin are deemed "recently dead"; they might
* still be visible to some open transaction, so we can't remove them,
* even if we see that the deleting transaction has committed.
*/
HTSV_Result
HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin,
Buffer buffer)
{
/*
* Has inserting transaction committed?
*
* If the inserting transaction aborted, then the tuple was never visible
* to any other transaction, so we can delete it immediately.
*/
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return HEAPTUPLE_DEAD;
else if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return HEAPTUPLE_DELETE_IN_PROGRESS;
if (TransactionIdIsInProgress(xvac))
return HEAPTUPLE_DELETE_IN_PROGRESS;
if (TransactionIdDidCommit(xvac))
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HEAPTUPLE_DEAD;
}
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return HEAPTUPLE_INSERT_IN_PROGRESS;
if (TransactionIdIsInProgress(xvac))
return HEAPTUPLE_INSERT_IN_PROGRESS;
if (TransactionIdDidCommit(xvac))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
InvalidTransactionId);
else
{
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HEAPTUPLE_DEAD;
}
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return HEAPTUPLE_INSERT_IN_PROGRESS;
if (tuple->t_infomask & HEAP_IS_LOCKED)
return HEAPTUPLE_INSERT_IN_PROGRESS;
/* inserted and then deleted by same xact */
return HEAPTUPLE_DELETE_IN_PROGRESS;
}
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
HeapTupleHeaderGetXmin(tuple));
else
{
/*
* Not in Progress, Not Committed, so either Aborted or crashed
*/
SetHintBits(tuple, buffer, HEAP_XMIN_INVALID,
InvalidTransactionId);
return HEAPTUPLE_DEAD;
}
/*
* At this point the xmin is known committed, but we might not have
* been able to set the hint bit yet; so we can no longer Assert that
* it's set.
*/
}
/*
* Okay, the inserter committed, so it was good at some point. Now what
* about the deleting transaction?
*/
if (tuple->t_infomask & HEAP_XMAX_INVALID)
return HEAPTUPLE_LIVE;
if (tuple->t_infomask & HEAP_IS_LOCKED)
{
/*
* "Deleting" xact really only locked it, so the tuple is live in any
* case. However, we should make sure that either XMAX_COMMITTED or
* XMAX_INVALID gets set once the xact is gone, to reduce the costs of
* examining the tuple for future xacts. Also, marking dead
* MultiXacts as invalid here provides defense against MultiXactId
* wraparound (see also comments in heap_freeze_tuple()).
*/
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
if (MultiXactIdIsRunning(HeapTupleHeaderGetXmax(tuple)))
return HEAPTUPLE_LIVE;
}
else
{
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return HEAPTUPLE_LIVE;
}
/*
* We don't really care whether xmax did commit, abort or crash.
* We know that xmax did lock the tuple, but it did not and will
* never actually update it.
*/
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
}
return HEAPTUPLE_LIVE;
}
if (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
{
/* MultiXacts are currently only allowed to lock tuples */
Assert(tuple->t_infomask & HEAP_IS_LOCKED);
return HEAPTUPLE_LIVE;
}
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return HEAPTUPLE_DELETE_IN_PROGRESS;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
SetHintBits(tuple, buffer, HEAP_XMAX_COMMITTED,
HeapTupleHeaderGetXmax(tuple));
else
{
/*
* Not in Progress, Not Committed, so either Aborted or crashed
*/
SetHintBits(tuple, buffer, HEAP_XMAX_INVALID,
InvalidTransactionId);
return HEAPTUPLE_LIVE;
}
/*
* At this point the xmax is known committed, but we might not have
* been able to set the hint bit yet; so we can no longer Assert that
* it's set.
*/
}
/*
* Deleter committed, but check special cases.
*/
if (TransactionIdEquals(HeapTupleHeaderGetXmin(tuple),
HeapTupleHeaderGetXmax(tuple)))
{
/*
* Inserter also deleted it, so it was never visible to anyone else.
* However, we can only remove it early if it's not an updated tuple;
* else its parent tuple is linking to it via t_ctid, and this tuple
* mustn't go away before the parent does.
*/
if (!(tuple->t_infomask & HEAP_UPDATED))
return HEAPTUPLE_DEAD;
}
if (!TransactionIdPrecedes(HeapTupleHeaderGetXmax(tuple), OldestXmin))
{
/* deleting xact is too recent, tuple could still be visible */
return HEAPTUPLE_RECENTLY_DEAD;
}
/* Otherwise, it's dead and removable */
return HEAPTUPLE_DEAD;
}
Datum
heap_page_items(PG_FUNCTION_ARGS)
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
heap_page_items_state *inter_call_data = NULL;
FuncCallContext *fctx;
int raw_page_size;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to use raw page functions"))));
raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
MemoryContext mctx;
if (raw_page_size < SizeOfPageHeaderData)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input page too small (%d bytes)", raw_page_size)));
fctx = SRF_FIRSTCALL_INIT();
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
inter_call_data = palloc(sizeof(heap_page_items_state));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
inter_call_data->tupd = tupdesc;
inter_call_data->offset = FirstOffsetNumber;
inter_call_data->page = VARDATA(raw_page);
fctx->max_calls = PageGetMaxOffsetNumber(inter_call_data->page);
fctx->user_fctx = inter_call_data;
MemoryContextSwitchTo(mctx);
}
fctx = SRF_PERCALL_SETUP();
inter_call_data = fctx->user_fctx;
if (fctx->call_cntr < fctx->max_calls)
{
Page page = inter_call_data->page;
HeapTuple resultTuple;
Datum result;
ItemId id;
Datum values[13];
bool nulls[13];
uint16 lp_offset;
uint16 lp_flags;
uint16 lp_len;
memset(nulls, 0, sizeof(nulls));
/* Extract information from the line pointer */
id = PageGetItemId(page, inter_call_data->offset);
lp_offset = ItemIdGetOffset(id);
lp_flags = ItemIdGetFlags(id);
lp_len = ItemIdGetLength(id);
values[0] = UInt16GetDatum(inter_call_data->offset);
values[1] = UInt16GetDatum(lp_offset);
values[2] = UInt16GetDatum(lp_flags);
values[3] = UInt16GetDatum(lp_len);
/*
* We do just enough validity checking to make sure we don't reference
* data outside the page passed to us. The page could be corrupt in
* many other ways, but at least we won't crash.
*/
if (ItemIdHasStorage(id) &&
lp_len >= sizeof(HeapTupleHeader) &&
lp_offset == MAXALIGN(lp_offset) &&
lp_offset + lp_len <= raw_page_size)
{
HeapTupleHeader tuphdr;
int bits_len;
/* Extract information from the tuple header */
tuphdr = (HeapTupleHeader) PageGetItem(page, id);
values[4] = UInt32GetDatum(HeapTupleHeaderGetXmin(tuphdr));
values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr)); /* shared with xvac */
values[7] = PointerGetDatum(&tuphdr->t_ctid);
values[8] = UInt32GetDatum(tuphdr->t_infomask2);
values[9] = UInt32GetDatum(tuphdr->t_infomask);
values[10] = UInt8GetDatum(tuphdr->t_hoff);
/*
* We already checked that the item as is completely within the
* raw page passed to us, with the length given in the line
* pointer.. Let's check that t_hoff doesn't point over lp_len,
* before using it to access t_bits and oid.
*/
if (tuphdr->t_hoff >= sizeof(HeapTupleHeader) &&
tuphdr->t_hoff <= lp_len)
{
if (tuphdr->t_infomask & HEAP_HASNULL)
{
bits_len = tuphdr->t_hoff -
(((char *) tuphdr->t_bits) -((char *) tuphdr));
values[11] = CStringGetTextDatum(
bits_to_text(tuphdr->t_bits, bits_len * 8));
}
else
nulls[11] = true;
if (tuphdr->t_infomask & HEAP_HASOID)
values[12] = HeapTupleHeaderGetOid(tuphdr);
else
nulls[12] = true;
}
else
{
nulls[11] = true;
nulls[12] = true;
}
}
else
{
/*
* The line pointer is not used, or it's invalid. Set the rest of
* the fields to NULL
*/
int i;
for (i = 4; i <= 12; i++)
nulls[i] = true;
}
/* Build and return the result tuple. */
resultTuple = heap_form_tuple(inter_call_data->tupd, values, nulls);
result = HeapTupleGetDatum(resultTuple);
inter_call_data->offset++;
SRF_RETURN_NEXT(fctx, result);
}
else
SRF_RETURN_DONE(fctx);
}
/*
* Disallow use of an uncommitted pg_enum tuple.
*
* We need to make sure that uncommitted enum values don't get into indexes.
* If they did, and if we then rolled back the pg_enum addition, we'd have
* broken the index because value comparisons will not work reliably without
* an underlying pg_enum entry. (Note that removal of the heap entry
* containing an enum value is not sufficient to ensure that it doesn't appear
* in upper levels of indexes.) To do this we prevent an uncommitted row from
* being used for any SQL-level purpose. This is stronger than necessary,
* since the value might not be getting inserted into a table or there might
* be no index on its column, but it's easy to enforce centrally.
*
* However, it's okay to allow use of uncommitted values belonging to enum
* types that were themselves created in the same transaction, because then
* any such index would also be new and would go away altogether on rollback.
* (This case is required by pg_upgrade.)
*
* This function needs to be called (directly or indirectly) in any of the
* functions below that could return an enum value to SQL operations.
*/
static void
check_safe_enum_use(HeapTuple enumval_tup)
{
TransactionId xmin;
Form_pg_enum en;
HeapTuple enumtyp_tup;
/*
* If the row is hinted as committed, it's surely safe. This provides a
* fast path for all normal use-cases.
*/
if (HeapTupleHeaderXminCommitted(enumval_tup->t_data))
return;
/*
* Usually, a row would get hinted as committed when it's read or loaded
* into syscache; but just in case not, let's check the xmin directly.
*/
xmin = HeapTupleHeaderGetXmin(enumval_tup->t_data);
if (!TransactionIdIsInProgress(xmin) &&
TransactionIdDidCommit(xmin))
return;
/* It is a new enum value, so check to see if the whole enum is new */
en = (Form_pg_enum) GETSTRUCT(enumval_tup);
enumtyp_tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(en->enumtypid));
if (!HeapTupleIsValid(enumtyp_tup))
elog(ERROR, "cache lookup failed for type %u", en->enumtypid);
/*
* We insist that the type have been created in the same (sub)transaction
* as the enum value. It would be safe to allow the type's originating
* xact to be a subcommitted child of the enum value's xact, but not vice
* versa (since we might now be in a subxact of the type's originating
* xact, which could roll back along with the enum value's subxact). The
* former case seems a sufficiently weird usage pattern as to not be worth
* spending code for, so we're left with a simple equality check.
*
* We also insist that the type's pg_type row not be HEAP_UPDATED. If it
* is, we can't tell whether the row was created or only modified in the
* apparent originating xact, so it might be older than that xact. (We do
* not worry whether the enum value is HEAP_UPDATED; if it is, we might
* think it's too new and throw an unnecessary error, but we won't allow
* an unsafe case.)
*/
if (xmin == HeapTupleHeaderGetXmin(enumtyp_tup->t_data) &&
!(enumtyp_tup->t_data->t_infomask & HEAP_UPDATED))
{
/* same (sub)transaction, so safe */
ReleaseSysCache(enumtyp_tup);
return;
}
/*
* There might well be other tests we could do here to narrow down the
* unsafe conditions, but for now just raise an exception.
*/
ereport(ERROR,
(errcode(ERRCODE_UNSAFE_NEW_ENUM_VALUE_USAGE),
errmsg("unsafe use of new value \"%s\" of enum type %s",
NameStr(en->enumlabel),
format_type_be(en->enumtypid)),
errhint("New enum values must be committed before they can be used.")));
}
static plperl_proc_desc *
compile_plperl_function(Oid fn_oid, bool is_trigger)
{
HeapTuple procTup;
Form_pg_proc procStruct;
char internal_proname[64];
int proname_len;
plperl_proc_desc *prodesc = NULL;
int i;
SV **svp;
/* We'll need the pg_proc tuple in any case... */
procTup = SearchSysCache(PROCOID,
ObjectIdGetDatum(fn_oid),
0, 0, 0);
if (!HeapTupleIsValid(procTup))
elog(ERROR, "cache lookup failed for function %u", fn_oid);
procStruct = (Form_pg_proc) GETSTRUCT(procTup);
/************************************************************
* Build our internal proc name from the functions Oid
************************************************************/
if (!is_trigger)
sprintf(internal_proname, "__PLPerl_proc_%u", fn_oid);
else
sprintf(internal_proname, "__PLPerl_proc_%u_trigger", fn_oid);
proname_len = strlen(internal_proname);
/************************************************************
* Lookup the internal proc name in the hashtable
************************************************************/
svp = hv_fetch(plperl_proc_hash, internal_proname, proname_len, FALSE);
if (svp)
{
bool uptodate;
prodesc = (plperl_proc_desc *) SvIV(*svp);
/************************************************************
* If it's present, must check whether it's still up to date.
* This is needed because CREATE OR REPLACE FUNCTION can modify the
* function's pg_proc entry without changing its OID.
************************************************************/
uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
prodesc->fn_cmin == HeapTupleHeaderGetCmin(procTup->t_data));
if (!uptodate)
{
/* need we delete old entry? */
prodesc = NULL;
}
}
/************************************************************
* If we haven't found it in the hashtable, we analyze
* the functions arguments and returntype and store
* the in-/out-functions in the prodesc block and create
* a new hashtable entry for it.
*
* Then we load the procedure into the Perl interpreter.
************************************************************/
if (prodesc == NULL)
{
HeapTuple langTup;
HeapTuple typeTup;
Form_pg_language langStruct;
Form_pg_type typeStruct;
Datum prosrcdatum;
bool isnull;
char *proc_source;
/************************************************************
* Allocate a new procedure description block
************************************************************/
prodesc = (plperl_proc_desc *) malloc(sizeof(plperl_proc_desc));
if (prodesc == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
MemSet(prodesc, 0, sizeof(plperl_proc_desc));
prodesc->proname = strdup(internal_proname);
prodesc->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
prodesc->fn_cmin = HeapTupleHeaderGetCmin(procTup->t_data);
/* Remember if function is STABLE/IMMUTABLE */
prodesc->fn_readonly =
(procStruct->provolatile != PROVOLATILE_VOLATILE);
/************************************************************
* Lookup the pg_language tuple by Oid
************************************************************/
langTup = SearchSysCache(LANGOID,
ObjectIdGetDatum(procStruct->prolang),
0, 0, 0);
if (!HeapTupleIsValid(langTup))
{
free(prodesc->proname);
free(prodesc);
elog(ERROR, "cache lookup failed for language %u",
procStruct->prolang);
}
langStruct = (Form_pg_language) GETSTRUCT(langTup);
prodesc->lanpltrusted = langStruct->lanpltrusted;
ReleaseSysCache(langTup);
/************************************************************
* Get the required information for input conversion of the
* return value.
************************************************************/
if (!is_trigger)
{
typeTup = SearchSysCache(TYPEOID,
ObjectIdGetDatum(procStruct->prorettype),
0, 0, 0);
if (!HeapTupleIsValid(typeTup))
{
free(prodesc->proname);
free(prodesc);
elog(ERROR, "cache lookup failed for type %u",
procStruct->prorettype);
}
typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
/* Disallow pseudotype result, except VOID or RECORD */
if (typeStruct->typtype == 'p')
{
if (procStruct->prorettype == VOIDOID ||
procStruct->prorettype == RECORDOID)
/* okay */ ;
else if (procStruct->prorettype == TRIGGEROID)
{
free(prodesc->proname);
free(prodesc);
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("trigger functions may only be called "
"as triggers")));
}
else
{
free(prodesc->proname);
free(prodesc);
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("plperl functions cannot return type %s",
format_type_be(procStruct->prorettype))));
}
}
prodesc->result_oid = procStruct->prorettype;
prodesc->fn_retisset = procStruct->proretset;
prodesc->fn_retistuple = (typeStruct->typtype == 'c' ||
procStruct->prorettype == RECORDOID);
prodesc->fn_retisarray =
(typeStruct->typlen == -1 && typeStruct->typelem);
perm_fmgr_info(typeStruct->typinput, &(prodesc->result_in_func));
prodesc->result_typioparam = getTypeIOParam(typeTup);
ReleaseSysCache(typeTup);
}
/************************************************************
* Get the required information for output conversion
* of all procedure arguments
************************************************************/
if (!is_trigger)
{
prodesc->nargs = procStruct->pronargs;
for (i = 0; i < prodesc->nargs; i++)
{
typeTup = SearchSysCache(TYPEOID,
ObjectIdGetDatum(procStruct->proargtypes.values[i]),
0, 0, 0);
if (!HeapTupleIsValid(typeTup))
{
free(prodesc->proname);
free(prodesc);
elog(ERROR, "cache lookup failed for type %u",
procStruct->proargtypes.values[i]);
}
typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
/* Disallow pseudotype argument */
if (typeStruct->typtype == 'p')
{
free(prodesc->proname);
free(prodesc);
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("plperl functions cannot take type %s",
format_type_be(procStruct->proargtypes.values[i]))));
}
if (typeStruct->typtype == 'c')
prodesc->arg_is_rowtype[i] = true;
else
{
prodesc->arg_is_rowtype[i] = false;
perm_fmgr_info(typeStruct->typoutput,
&(prodesc->arg_out_func[i]));
}
ReleaseSysCache(typeTup);
}
}
/************************************************************
* create the text of the anonymous subroutine.
* we do not use a named subroutine so that we can call directly
* through the reference.
************************************************************/
prosrcdatum = SysCacheGetAttr(PROCOID, procTup,
Anum_pg_proc_prosrc, &isnull);
if (isnull)
elog(ERROR, "null prosrc");
proc_source = DatumGetCString(DirectFunctionCall1(textout,
prosrcdatum));
/************************************************************
* Create the procedure in the interpreter
************************************************************/
prodesc->reference = plperl_create_sub(proc_source, prodesc->lanpltrusted);
pfree(proc_source);
if (!prodesc->reference) /* can this happen? */
{
free(prodesc->proname);
free(prodesc);
elog(ERROR, "could not create internal procedure \"%s\"",
internal_proname);
}
hv_store(plperl_proc_hash, internal_proname, proname_len,
newSViv((IV) prodesc), 0);
}
ReleaseSysCache(procTup);
return prodesc;
}
/*
* get_relation_info -
* Retrieves catalog information for a given relation.
*
* Given the Oid of the relation, return the following info into fields
* of the RelOptInfo struct:
*
* min_attr lowest valid AttrNumber
* max_attr highest valid AttrNumber
* indexlist list of IndexOptInfos for relation's indexes
* pages number of pages
* tuples number of tuples
*
* Also, initialize the attr_needed[] and attr_widths[] arrays. In most
* cases these are left as zeroes, but sometimes we need to compute attr
* widths here, and we may as well cache the results for costsize.c.
*
* If inhparent is true, all we need to do is set up the attr arrays:
* the RelOptInfo actually represents the appendrel formed by an inheritance
* tree, and so the parent rel's physical size and index information isn't
* important for it.
*/
void
get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
RelOptInfo *rel)
{
Index varno = rel->relid;
Relation relation;
bool hasindex;
List *indexinfos = NIL;
/*
* We need not lock the relation since it was already locked, either by
* the rewriter or when expand_inherited_rtentry() added it to the query's
* rangetable.
*/
relation = heap_open(relationObjectId, NoLock);
/* Temporary and unlogged relations are inaccessible during recovery. */
if (!RelationNeedsWAL(relation) && RecoveryInProgress())
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot access temporary or unlogged relations during recovery")));
rel->min_attr = FirstLowInvalidHeapAttributeNumber + 1;
rel->max_attr = RelationGetNumberOfAttributes(relation);
rel->reltablespace = RelationGetForm(relation)->reltablespace;
Assert(rel->max_attr >= rel->min_attr);
rel->attr_needed = (Relids *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids));
rel->attr_widths = (int32 *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32));
/*
* Estimate relation size --- unless it's an inheritance parent, in which
* case the size will be computed later in set_append_rel_pathlist, and we
* must leave it zero for now to avoid bollixing the total_table_pages
* calculation.
*/
if (!inhparent)
estimate_rel_size(relation, rel->attr_widths - rel->min_attr,
&rel->pages, &rel->tuples, &rel->allvisfrac);
/*
* Make list of indexes. Ignore indexes on system catalogs if told to.
* Don't bother with indexes for an inheritance parent, either.
*/
if (inhparent ||
(IgnoreSystemIndexes && IsSystemClass(relation->rd_rel)))
hasindex = false;
else
hasindex = relation->rd_rel->relhasindex;
if (hasindex)
{
List *indexoidlist;
ListCell *l;
LOCKMODE lmode;
indexoidlist = RelationGetIndexList(relation);
/*
* For each index, we get the same type of lock that the executor will
* need, and do not release it. This saves a couple of trips to the
* shared lock manager while not creating any real loss of
* concurrency, because no schema changes could be happening on the
* index while we hold lock on the parent rel, and neither lock type
* blocks any other kind of index operation.
*/
if (rel->relid == root->parse->resultRelation)
lmode = RowExclusiveLock;
else
lmode = AccessShareLock;
foreach(l, indexoidlist)
{
Oid indexoid = lfirst_oid(l);
Relation indexRelation;
Form_pg_index index;
IndexOptInfo *info;
int ncolumns;
int i;
/*
* Extract info from the relation descriptor for the index.
*/
indexRelation = index_open(indexoid, lmode);
index = indexRelation->rd_index;
/*
* Ignore invalid indexes, since they can't safely be used for
* queries. Note that this is OK because the data structure we
* are constructing is only used by the planner --- the executor
* still needs to insert into "invalid" indexes!
*/
if (!index->indisvalid)
{
index_close(indexRelation, NoLock);
continue;
}
/*
* If the index is valid, but cannot yet be used, ignore it; but
* mark the plan we are generating as transient. See
* src/backend/access/heap/README.HOT for discussion.
*/
if (index->indcheckxmin &&
!TransactionIdPrecedes(HeapTupleHeaderGetXmin(indexRelation->rd_indextuple->t_data),
TransactionXmin))
{
root->glob->transientPlan = true;
index_close(indexRelation, NoLock);
continue;
}
info = makeNode(IndexOptInfo);
info->indexoid = index->indexrelid;
info->reltablespace =
RelationGetForm(indexRelation)->reltablespace;
info->rel = rel;
info->ncolumns = ncolumns = index->indnatts;
info->indexkeys = (int *) palloc(sizeof(int) * ncolumns);
info->indexcollations = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->opfamily = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->opcintype = (Oid *) palloc(sizeof(Oid) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
info->indexkeys[i] = index->indkey.values[i];
info->indexcollations[i] = indexRelation->rd_indcollation[i];
info->opfamily[i] = indexRelation->rd_opfamily[i];
info->opcintype[i] = indexRelation->rd_opcintype[i];
}
info->relam = indexRelation->rd_rel->relam;
info->amcostestimate = indexRelation->rd_am->amcostestimate;
info->canreturn = index_can_return(indexRelation);
info->amcanorderbyop = indexRelation->rd_am->amcanorderbyop;
info->amoptionalkey = indexRelation->rd_am->amoptionalkey;
info->amsearcharray = indexRelation->rd_am->amsearcharray;
info->amsearchnulls = indexRelation->rd_am->amsearchnulls;
info->amhasgettuple = OidIsValid(indexRelation->rd_am->amgettuple);
info->amhasgetbitmap = OidIsValid(indexRelation->rd_am->amgetbitmap);
/*
* Fetch the ordering information for the index, if any.
*/
if (info->relam == BTREE_AM_OID)
{
/*
* If it's a btree index, we can use its opfamily OIDs
* directly as the sort ordering opfamily OIDs.
*/
Assert(indexRelation->rd_am->amcanorder);
info->sortopfamily = info->opfamily;
info->reverse_sort = (bool *) palloc(sizeof(bool) * ncolumns);
info->nulls_first = (bool *) palloc(sizeof(bool) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
int16 opt = indexRelation->rd_indoption[i];
info->reverse_sort[i] = (opt & INDOPTION_DESC) != 0;
info->nulls_first[i] = (opt & INDOPTION_NULLS_FIRST) != 0;
}
}
else if (indexRelation->rd_am->amcanorder)
{
/*
* Otherwise, identify the corresponding btree opfamilies by
* trying to map this index's "<" operators into btree. Since
* "<" uniquely defines the behavior of a sort order, this is
* a sufficient test.
*
* XXX This method is rather slow and also requires the
* undesirable assumption that the other index AM numbers its
* strategies the same as btree. It'd be better to have a way
* to explicitly declare the corresponding btree opfamily for
* each opfamily of the other index type. But given the lack
* of current or foreseeable amcanorder index types, it's not
* worth expending more effort on now.
*/
info->sortopfamily = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->reverse_sort = (bool *) palloc(sizeof(bool) * ncolumns);
info->nulls_first = (bool *) palloc(sizeof(bool) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
int16 opt = indexRelation->rd_indoption[i];
Oid ltopr;
Oid btopfamily;
Oid btopcintype;
int16 btstrategy;
info->reverse_sort[i] = (opt & INDOPTION_DESC) != 0;
info->nulls_first[i] = (opt & INDOPTION_NULLS_FIRST) != 0;
ltopr = get_opfamily_member(info->opfamily[i],
info->opcintype[i],
info->opcintype[i],
BTLessStrategyNumber);
if (OidIsValid(ltopr) &&
get_ordering_op_properties(ltopr,
&btopfamily,
&btopcintype,
&btstrategy) &&
btopcintype == info->opcintype[i] &&
btstrategy == BTLessStrategyNumber)
{
/* Successful mapping */
info->sortopfamily[i] = btopfamily;
}
else
{
/* Fail ... quietly treat index as unordered */
info->sortopfamily = NULL;
info->reverse_sort = NULL;
info->nulls_first = NULL;
break;
}
}
}
else
{
info->sortopfamily = NULL;
info->reverse_sort = NULL;
info->nulls_first = NULL;
}
/*
* Fetch the index expressions and predicate, if any. We must
* modify the copies we obtain from the relcache to have the
* correct varno for the parent relation, so that they match up
* correctly against qual clauses.
*/
info->indexprs = RelationGetIndexExpressions(indexRelation);
info->indpred = RelationGetIndexPredicate(indexRelation);
if (info->indexprs && varno != 1)
ChangeVarNodes((Node *) info->indexprs, 1, varno, 0);
if (info->indpred && varno != 1)
ChangeVarNodes((Node *) info->indpred, 1, varno, 0);
/* Build targetlist using the completed indexprs data */
info->indextlist = build_index_tlist(root, info, relation);
info->predOK = false; /* set later in indxpath.c */
info->unique = index->indisunique;
info->immediate = index->indimmediate;
info->hypothetical = false;
/*
* Estimate the index size. If it's not a partial index, we lock
* the number-of-tuples estimate to equal the parent table; if it
* is partial then we have to use the same methods as we would for
* a table, except we can be sure that the index is not larger
* than the table.
*/
if (info->indpred == NIL)
{
info->pages = RelationGetNumberOfBlocks(indexRelation);
info->tuples = rel->tuples;
}
else
{
double allvisfrac; /* dummy */
estimate_rel_size(indexRelation, NULL,
&info->pages, &info->tuples, &allvisfrac);
if (info->tuples > rel->tuples)
info->tuples = rel->tuples;
}
index_close(indexRelation, NoLock);
indexinfos = lcons(info, indexinfos);
}
list_free(indexoidlist);
}
/*
* HeapTupleSatisfiesVacuum
*
* Determine the status of tuples for VACUUM purposes. Here, what
* we mainly want to know is if a tuple is potentially visible to *any*
* running transaction. If so, it can't be removed yet by VACUUM.
*
* OldestXmin is a cutoff XID (obtained from GetOldestXmin()). Tuples
* deleted by XIDs >= OldestXmin are deemed "recently dead"; they might
* still be visible to some open transaction, so we can't remove them,
* even if we see that the deleting transaction has committed.
*/
HTSV_Result
HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin)
{
/*
* Has inserting transaction committed?
*
* If the inserting transaction aborted, then the tuple was never visible
* to any other transaction, so we can delete it immediately.
*/
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return HEAPTUPLE_DEAD;
else if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return HEAPTUPLE_DELETE_IN_PROGRESS;
if (TransactionIdIsInProgress(xvac))
return HEAPTUPLE_DELETE_IN_PROGRESS;
if (TransactionIdDidCommit(xvac))
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return HEAPTUPLE_DEAD;
}
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return HEAPTUPLE_INSERT_IN_PROGRESS;
if (TransactionIdIsInProgress(xvac))
return HEAPTUPLE_INSERT_IN_PROGRESS;
if (TransactionIdDidCommit(xvac))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return HEAPTUPLE_DEAD;
}
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return HEAPTUPLE_INSERT_IN_PROGRESS;
Assert(HeapTupleHeaderGetXmin(tuple) ==
HeapTupleHeaderGetXmax(tuple));
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return HEAPTUPLE_INSERT_IN_PROGRESS;
/* inserted and then deleted by same xact */
return HEAPTUPLE_DELETE_IN_PROGRESS;
}
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
/*
* Not in Progress, Not Committed, so either Aborted or
* crashed
*/
tuple->t_infomask |= HEAP_XMIN_INVALID;
return HEAPTUPLE_DEAD;
}
/* Should only get here if we set XMIN_COMMITTED */
Assert(tuple->t_infomask & HEAP_XMIN_COMMITTED);
}
/*
* Okay, the inserter committed, so it was good at some point. Now
* what about the deleting transaction?
*/
if (tuple->t_infomask & HEAP_XMAX_INVALID)
return HEAPTUPLE_LIVE;
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
{
/*
* "Deleting" xact really only marked it for update, so the tuple
* is live in any case. However, we must make sure that either
* XMAX_COMMITTED or XMAX_INVALID gets set once the xact is gone;
* otherwise it is unsafe to recycle CLOG status after vacuuming.
*/
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return HEAPTUPLE_LIVE;
/*
* We don't really care whether xmax did commit, abort or
* crash. We know that xmax did mark the tuple for update, but
* it did not and will never actually update it.
*/
tuple->t_infomask |= HEAP_XMAX_INVALID;
}
return HEAPTUPLE_LIVE;
}
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return HEAPTUPLE_DELETE_IN_PROGRESS;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
tuple->t_infomask |= HEAP_XMAX_COMMITTED;
else
{
/*
* Not in Progress, Not Committed, so either Aborted or
* crashed
*/
tuple->t_infomask |= HEAP_XMAX_INVALID;
return HEAPTUPLE_LIVE;
}
/* Should only get here if we set XMAX_COMMITTED */
Assert(tuple->t_infomask & HEAP_XMAX_COMMITTED);
}
/*
* Deleter committed, but check special cases.
*/
if (TransactionIdEquals(HeapTupleHeaderGetXmin(tuple),
HeapTupleHeaderGetXmax(tuple)))
{
/*
* Inserter also deleted it, so it was never visible to anyone
* else. However, we can only remove it early if it's not an
* updated tuple; else its parent tuple is linking to it via t_ctid,
* and this tuple mustn't go away before the parent does.
*/
if (!(tuple->t_infomask & HEAP_UPDATED))
return HEAPTUPLE_DEAD;
}
if (!TransactionIdPrecedes(HeapTupleHeaderGetXmax(tuple), OldestXmin))
{
/* deleting xact is too recent, tuple could still be visible */
return HEAPTUPLE_RECENTLY_DEAD;
}
/* Otherwise, it's dead and removable */
return HEAPTUPLE_DEAD;
}
/*
* HeapTupleSatisfiesSnapshot
* True iff heap tuple is valid for the given snapshot.
*
* Here, we consider the effects of:
* all transactions committed as of the time of the given snapshot
* previous commands of this transaction
*
* Does _not_ include:
* transactions shown as in-progress by the snapshot
* transactions started after the snapshot was taken
* changes made by the current command
*
* This is the same as HeapTupleSatisfiesNow, except that transactions that
* were in progress or as yet unstarted when the snapshot was taken will
* be treated as uncommitted, even if they have committed by now.
*
* (Notice, however, that the tuple status hint bits will be updated on the
* basis of the true state of the transaction, even if we then pretend we
* can't see it.)
*/
bool
HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
{
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return false;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return false;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return false;
if (TransactionIdDidCommit(xvac))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (HeapTupleHeaderGetCmin(tuple) >= snapshot->curcid)
return false; /* inserted after scan started */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return true;
Assert(TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)));
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
if (HeapTupleHeaderGetCmax(tuple) >= snapshot->curcid)
return true; /* deleted after scan started */
else
return false; /* deleted before scan started */
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
return false;
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
/*
* By here, the inserting transaction has committed - have to check
* when...
*/
if (TransactionIdFollowsOrEquals(HeapTupleHeaderGetXmin(tuple),
snapshot->xmin))
{
uint32 i;
if (TransactionIdFollowsOrEquals(HeapTupleHeaderGetXmin(tuple),
snapshot->xmax))
return false;
for (i = 0; i < snapshot->xcnt; i++)
{
if (TransactionIdEquals(HeapTupleHeaderGetXmin(tuple),
snapshot->xip[i]))
return false;
}
}
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return true;
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
if (!(tuple->t_infomask & HEAP_XMAX_COMMITTED))
{
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (HeapTupleHeaderGetCmax(tuple) >= snapshot->curcid)
return true; /* deleted after scan started */
else
return false; /* deleted before scan started */
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
return true;
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMAX_INVALID;
return true;
}
/* xmax transaction committed */
tuple->t_infomask |= HEAP_XMAX_COMMITTED;
}
/*
* OK, the deleting transaction committed too ... but when?
*/
if (TransactionIdFollowsOrEquals(HeapTupleHeaderGetXmax(tuple), snapshot->xmin))
{
uint32 i;
if (TransactionIdFollowsOrEquals(HeapTupleHeaderGetXmax(tuple),
snapshot->xmax))
return true;
for (i = 0; i < snapshot->xcnt; i++)
{
if (TransactionIdEquals(HeapTupleHeaderGetXmax(tuple), snapshot->xip[i]))
return true;
}
}
return false;
}
/*
* HeapTupleSatisfiesDirty
* True iff heap tuple is valid including effects of open transactions.
*
* Here, we consider the effects of:
* all committed and in-progress transactions (as of the current instant)
* previous commands of this transaction
* changes made by the current command
*
* This is essentially like HeapTupleSatisfiesItself as far as effects of
* the current transaction and committed/aborted xacts are concerned.
* However, we also include the effects of other xacts still in progress.
*
* Returns extra information in the global variable SnapshotDirty, namely
* xids of concurrent xacts that affected the tuple. Also, the tuple's
* t_ctid (forward link) is returned if it's being updated.
*/
bool
HeapTupleSatisfiesDirty(HeapTupleHeader tuple)
{
SnapshotDirty->xmin = SnapshotDirty->xmax = InvalidTransactionId;
ItemPointerSetInvalid(&(SnapshotDirty->tid));
if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple->t_infomask & HEAP_XMIN_INVALID)
return false;
if (tuple->t_infomask & HEAP_MOVED_OFF)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (TransactionIdIsCurrentTransactionId(xvac))
return false;
if (!TransactionIdIsInProgress(xvac))
{
if (TransactionIdDidCommit(xvac))
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
}
}
else if (tuple->t_infomask & HEAP_MOVED_IN)
{
TransactionId xvac = HeapTupleHeaderGetXvac(tuple);
if (!TransactionIdIsCurrentTransactionId(xvac))
{
if (TransactionIdIsInProgress(xvac))
return false;
if (TransactionIdDidCommit(xvac))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
}
else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return true;
Assert(TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)));
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
return false;
}
else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
{
SnapshotDirty->xmin = HeapTupleHeaderGetXmin(tuple);
/* XXX shouldn't we fall through to look at xmax? */
return true; /* in insertion by other */
}
else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
tuple->t_infomask |= HEAP_XMIN_COMMITTED;
else
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMIN_INVALID;
return false;
}
}
/* by here, the inserting transaction has committed */
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */
return true;
if (tuple->t_infomask & HEAP_XMAX_COMMITTED)
{
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
SnapshotDirty->tid = tuple->t_ctid;
return false; /* updated by other */
}
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
{
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return true;
return false;
}
if (TransactionIdIsInProgress(HeapTupleHeaderGetXmax(tuple)))
{
SnapshotDirty->xmax = HeapTupleHeaderGetXmax(tuple);
return true;
}
if (!TransactionIdDidCommit(HeapTupleHeaderGetXmax(tuple)))
{
/* it must have aborted or crashed */
tuple->t_infomask |= HEAP_XMAX_INVALID;
return true;
}
/* xmax transaction committed */
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
{
tuple->t_infomask |= HEAP_XMAX_INVALID;
return true;
}
tuple->t_infomask |= HEAP_XMAX_COMMITTED;
SnapshotDirty->tid = tuple->t_ctid;
return false; /* updated by other */
}
/*
* get_relation_info -
* Retrieves catalog information for a given relation.
*
* Given the Oid of the relation, return the following info into fields
* of the RelOptInfo struct:
*
* min_attr lowest valid AttrNumber
* max_attr highest valid AttrNumber
* indexlist list of IndexOptInfos for relation's indexes
* pages number of pages
* tuples number of tuples
*
* Also, initialize the attr_needed[] and attr_widths[] arrays. In most
* cases these are left as zeroes, but sometimes we need to compute attr
* widths here, and we may as well cache the results for costsize.c.
*
* If inhparent is true, all we need to do is set up the attr arrays:
* the RelOptInfo actually represents the appendrel formed by an inheritance
* tree, and so the parent rel's physical size and index information isn't
* important for it.
*/
void
get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
RelOptInfo *rel)
{
Index varno = rel->relid;
Relation relation;
bool hasindex;
List *indexinfos = NIL;
/*
* We need not lock the relation since it was already locked, either by
* the rewriter or when expand_inherited_rtentry() added it to the query's
* rangetable.
*/
relation = heap_open(relationObjectId, NoLock);
rel->min_attr = FirstLowInvalidHeapAttributeNumber + 1;
rel->max_attr = RelationGetNumberOfAttributes(relation);
rel->reltablespace = RelationGetForm(relation)->reltablespace;
Assert(rel->max_attr >= rel->min_attr);
rel->attr_needed = (Relids *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids));
rel->attr_widths = (int32 *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32));
/*
* Estimate relation size --- unless it's an inheritance parent, in which
* case the size will be computed later in set_append_rel_pathlist, and we
* must leave it zero for now to avoid bollixing the total_table_pages
* calculation.
*/
if (!inhparent)
estimate_rel_size(relation, rel->attr_widths - rel->min_attr,
&rel->pages, &rel->tuples);
/*
* Make list of indexes. Ignore indexes on system catalogs if told to.
* Don't bother with indexes for an inheritance parent, either.
*/
if (inhparent ||
(IgnoreSystemIndexes && IsSystemClass(relation->rd_rel)))
hasindex = false;
else
hasindex = relation->rd_rel->relhasindex;
if (hasindex)
{
List *indexoidlist;
ListCell *l;
LOCKMODE lmode;
indexoidlist = RelationGetIndexList(relation);
/*
* For each index, we get the same type of lock that the executor will
* need, and do not release it. This saves a couple of trips to the
* shared lock manager while not creating any real loss of
* concurrency, because no schema changes could be happening on the
* index while we hold lock on the parent rel, and neither lock type
* blocks any other kind of index operation.
*/
if (rel->relid == root->parse->resultRelation)
lmode = RowExclusiveLock;
else
lmode = AccessShareLock;
foreach(l, indexoidlist)
{
Oid indexoid = lfirst_oid(l);
Relation indexRelation;
Form_pg_index index;
IndexOptInfo *info;
int ncolumns;
int i;
/*
* Extract info from the relation descriptor for the index.
*/
indexRelation = index_open(indexoid, lmode);
index = indexRelation->rd_index;
/*
* Ignore invalid indexes, since they can't safely be used for
* queries. Note that this is OK because the data structure we
* are constructing is only used by the planner --- the executor
* still needs to insert into "invalid" indexes!
*/
if (!index->indisvalid)
{
index_close(indexRelation, NoLock);
continue;
}
/*
* If the index is valid, but cannot yet be used, ignore it; but
* mark the plan we are generating as transient. See
* src/backend/access/heap/README.HOT for discussion.
*/
if (index->indcheckxmin &&
!TransactionIdPrecedes(HeapTupleHeaderGetXmin(indexRelation->rd_indextuple->t_data),
TransactionXmin))
{
root->glob->transientPlan = true;
index_close(indexRelation, NoLock);
continue;
}
info = makeNode(IndexOptInfo);
info->indexoid = index->indexrelid;
info->reltablespace =
RelationGetForm(indexRelation)->reltablespace;
info->rel = rel;
info->ncolumns = ncolumns = index->indnatts;
/*
* Allocate per-column info arrays. To save a few palloc cycles
* we allocate all the Oid-type arrays in one request. Note that
* the opfamily array needs an extra, terminating zero at the end.
* We pre-zero the ordering info in case the index is unordered.
*/
info->indexkeys = (int *) palloc(sizeof(int) * ncolumns);
info->opfamily = (Oid *) palloc0(sizeof(Oid) * (4 * ncolumns + 1));
info->opcintype = info->opfamily + (ncolumns + 1);
info->fwdsortop = info->opcintype + ncolumns;
info->revsortop = info->fwdsortop + ncolumns;
info->nulls_first = (bool *) palloc0(sizeof(bool) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
info->indexkeys[i] = index->indkey.values[i];
info->opfamily[i] = indexRelation->rd_opfamily[i];
info->opcintype[i] = indexRelation->rd_opcintype[i];
}
info->relam = indexRelation->rd_rel->relam;
info->amcostestimate = indexRelation->rd_am->amcostestimate;
info->amoptionalkey = indexRelation->rd_am->amoptionalkey;
info->amsearchnulls = indexRelation->rd_am->amsearchnulls;
info->amhasgettuple = OidIsValid(indexRelation->rd_am->amgettuple);
info->amhasgetbitmap = OidIsValid(indexRelation->rd_am->amgetbitmap);
/*
* Fetch the ordering operators associated with the index, if any.
* We expect that all ordering-capable indexes use btree's
* strategy numbers for the ordering operators.
*/
if (indexRelation->rd_am->amcanorder)
{
int nstrat = indexRelation->rd_am->amstrategies;
for (i = 0; i < ncolumns; i++)
{
int16 opt = indexRelation->rd_indoption[i];
int fwdstrat;
int revstrat;
if (opt & INDOPTION_DESC)
{
fwdstrat = BTGreaterStrategyNumber;
revstrat = BTLessStrategyNumber;
}
else
{
fwdstrat = BTLessStrategyNumber;
revstrat = BTGreaterStrategyNumber;
}
/*
* Index AM must have a fixed set of strategies for it to
* make sense to specify amcanorder, so we need not allow
* the case amstrategies == 0.
*/
if (fwdstrat > 0)
{
Assert(fwdstrat <= nstrat);
info->fwdsortop[i] = indexRelation->rd_operator[i * nstrat + fwdstrat - 1];
}
if (revstrat > 0)
{
Assert(revstrat <= nstrat);
info->revsortop[i] = indexRelation->rd_operator[i * nstrat + revstrat - 1];
}
info->nulls_first[i] = (opt & INDOPTION_NULLS_FIRST) != 0;
}
}
/*
* Fetch the index expressions and predicate, if any. We must
* modify the copies we obtain from the relcache to have the
* correct varno for the parent relation, so that they match up
* correctly against qual clauses.
*/
info->indexprs = RelationGetIndexExpressions(indexRelation);
info->indpred = RelationGetIndexPredicate(indexRelation);
if (info->indexprs && varno != 1)
ChangeVarNodes((Node *) info->indexprs, 1, varno, 0);
if (info->indpred && varno != 1)
ChangeVarNodes((Node *) info->indpred, 1, varno, 0);
info->predOK = false; /* set later in indxpath.c */
info->unique = index->indisunique;
/*
* Estimate the index size. If it's not a partial index, we lock
* the number-of-tuples estimate to equal the parent table; if it
* is partial then we have to use the same methods as we would for
* a table, except we can be sure that the index is not larger
* than the table.
*/
if (info->indpred == NIL)
{
info->pages = RelationGetNumberOfBlocks(indexRelation);
info->tuples = rel->tuples;
}
else
{
estimate_rel_size(indexRelation, NULL,
&info->pages, &info->tuples);
if (info->tuples > rel->tuples)
info->tuples = rel->tuples;
}
index_close(indexRelation, NoLock);
indexinfos = lcons(info, indexinfos);
}
list_free(indexoidlist);
}
/*
* Prune specified item pointer or a HOT chain originating at that item.
*
* If the item is an index-referenced tuple (i.e. not a heap-only tuple),
* the HOT chain is pruned by removing all DEAD tuples at the start of the HOT
* chain. We also prune any RECENTLY_DEAD tuples preceding a DEAD tuple.
* This is OK because a RECENTLY_DEAD tuple preceding a DEAD tuple is really
* DEAD, the OldestXmin test is just too coarse to detect it.
*
* The root line pointer is redirected to the tuple immediately after the
* latest DEAD tuple. If all tuples in the chain are DEAD, the root line
* pointer is marked LP_DEAD. (This includes the case of a DEAD simple
* tuple, which we treat as a chain of length 1.)
*
* OldestXmin is the cutoff XID used to identify dead tuples.
*
* We don't actually change the page here, except perhaps for hint-bit updates
* caused by HeapTupleSatisfiesVacuum. We just add entries to the arrays in
* prstate showing the changes to be made. Items to be redirected are added
* to the redirected[] array (two entries per redirection); items to be set to
* LP_DEAD state are added to nowdead[]; and items to be set to LP_UNUSED
* state are added to nowunused[].
*
* If redirect_move is true, we intend to get rid of redirecting line pointers,
* not just make redirection entries.
*
* Returns the number of tuples (to be) deleted from the page.
*/
static int
heap_prune_chain(Relation relation, Buffer buffer, OffsetNumber rootoffnum,
TransactionId OldestXmin,
PruneState *prstate,
bool redirect_move)
{
int ndeleted = 0;
Page dp = (Page) BufferGetPage(buffer);
TransactionId priorXmax = InvalidTransactionId;
ItemId rootlp;
HeapTupleHeader htup;
OffsetNumber latestdead = InvalidOffsetNumber,
redirect_target = InvalidOffsetNumber,
maxoff = PageGetMaxOffsetNumber(dp),
offnum;
OffsetNumber chainitems[MaxHeapTuplesPerPage];
int nchain = 0,
i;
rootlp = PageGetItemId(dp, rootoffnum);
/*
* If it's a heap-only tuple, then it is not the start of a HOT chain.
*/
if (ItemIdIsNormal(rootlp))
{
htup = (HeapTupleHeader) PageGetItem(dp, rootlp);
if (HeapTupleHeaderIsHeapOnly(htup))
{
/*
* If the tuple is DEAD and doesn't chain to anything else, mark
* it unused immediately. (If it does chain, we can only remove
* it as part of pruning its chain.)
*
* We need this primarily to handle aborted HOT updates, that is,
* XMIN_INVALID heap-only tuples. Those might not be linked to by
* any chain, since the parent tuple might be re-updated before
* any pruning occurs. So we have to be able to reap them
* separately from chain-pruning. (Note that
* HeapTupleHeaderIsHotUpdated will never return true for an
* XMIN_INVALID tuple, so this code will work even when there were
* sequential updates within the aborted transaction.)
*
* Note that we might first arrive at a dead heap-only tuple
* either here or while following a chain below. Whichever path
* gets there first will mark the tuple unused.
*/
if (HeapTupleSatisfiesVacuum(relation, htup, OldestXmin, buffer)
== HEAPTUPLE_DEAD && !HeapTupleHeaderIsHotUpdated(htup))
{
heap_prune_record_unused(prstate, rootoffnum);
ndeleted++;
}
/* Nothing more to do */
return ndeleted;
}
}
/* Start from the root tuple */
offnum = rootoffnum;
/* while not end of the chain */
for (;;)
{
ItemId lp;
bool tupdead,
recent_dead;
/* Some sanity checks */
if (offnum < FirstOffsetNumber || offnum > maxoff)
break;
/* If item is already processed, stop --- it must not be same chain */
if (prstate->marked[offnum])
break;
lp = PageGetItemId(dp, offnum);
/* Unused item obviously isn't part of the chain */
if (!ItemIdIsUsed(lp))
break;
/*
* If we are looking at the redirected root line pointer, jump to the
* first normal tuple in the chain. If we find a redirect somewhere
* else, stop --- it must not be same chain.
*/
if (ItemIdIsRedirected(lp))
{
if (nchain > 0)
break; /* not at start of chain */
chainitems[nchain++] = offnum;
offnum = ItemIdGetRedirect(rootlp);
continue;
}
/*
* Likewise, a dead item pointer can't be part of the chain. (We
* already eliminated the case of dead root tuple outside this
* function.)
*/
if (ItemIdIsDead(lp))
break;
Assert(ItemIdIsNormal(lp));
htup = (HeapTupleHeader) PageGetItem(dp, lp);
/*
* Check the tuple XMIN against prior XMAX, if any
*/
if (TransactionIdIsValid(priorXmax) &&
!TransactionIdEquals(HeapTupleHeaderGetXmin(htup), priorXmax))
break;
/*
* OK, this tuple is indeed a member of the chain.
*/
chainitems[nchain++] = offnum;
/*
* Check tuple's visibility status.
*/
tupdead = recent_dead = false;
switch (HeapTupleSatisfiesVacuum(relation, htup, OldestXmin, buffer))
{
case HEAPTUPLE_DEAD:
tupdead = true;
break;
case HEAPTUPLE_RECENTLY_DEAD:
recent_dead = true;
/*
* This tuple may soon become DEAD. Update the hint field so
* that the page is reconsidered for pruning in future.
*/
heap_prune_record_prunable(prstate,
HeapTupleHeaderGetXmax(htup));
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
/*
* This tuple may soon become DEAD. Update the hint field so
* that the page is reconsidered for pruning in future.
*/
heap_prune_record_prunable(prstate,
HeapTupleHeaderGetXmax(htup));
break;
case HEAPTUPLE_LIVE:
case HEAPTUPLE_INSERT_IN_PROGRESS:
/*
* If we wanted to optimize for aborts, we might consider
* marking the page prunable when we see INSERT_IN_PROGRESS.
* But we don't. See related decisions about when to mark the
* page prunable in heapam.c.
*/
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
/*
* Remember the last DEAD tuple seen. We will advance past
* RECENTLY_DEAD tuples just in case there's a DEAD one after them;
* but we can't advance past anything else. (XXX is it really worth
* continuing to scan beyond RECENTLY_DEAD? The case where we will
* find another DEAD tuple is a fairly unusual corner case.)
*/
if (tupdead)
latestdead = offnum;
else if (!recent_dead)
break;
/*
* If the tuple is not HOT-updated, then we are at the end of this
* HOT-update chain.
*/
if (!HeapTupleHeaderIsHotUpdated(htup))
break;
/*
* Advance to next chain member.
*/
Assert(ItemPointerGetBlockNumber(&htup->t_ctid) ==
BufferGetBlockNumber(buffer));
offnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
priorXmax = HeapTupleHeaderGetXmax(htup);
}
/*
* If we found a DEAD tuple in the chain, adjust the HOT chain so that all
* the DEAD tuples at the start of the chain are removed and the root line
* pointer is appropriately redirected.
*/
if (OffsetNumberIsValid(latestdead))
{
/*
* Mark as unused each intermediate item that we are able to remove
* from the chain.
*
* When the previous item is the last dead tuple seen, we are at the
* right candidate for redirection.
*/
for (i = 1; (i < nchain) && (chainitems[i - 1] != latestdead); i++)
{
heap_prune_record_unused(prstate, chainitems[i]);
ndeleted++;
}
/*
* If the root entry had been a normal tuple, we are deleting it, so
* count it in the result. But changing a redirect (even to DEAD
* state) doesn't count.
*/
if (ItemIdIsNormal(rootlp))
ndeleted++;
/*
* If the DEAD tuple is at the end of the chain, the entire chain is
* dead and the root line pointer can be marked dead. Otherwise just
* redirect the root to the correct chain member.
*/
if (i >= nchain)
heap_prune_record_dead(prstate, rootoffnum);
else
{
heap_prune_record_redirect(prstate, rootoffnum, chainitems[i]);
/* If the redirection will be a move, need more processing */
if (redirect_move)
redirect_target = chainitems[i];
}
}
else if (nchain < 2 && ItemIdIsRedirected(rootlp))
{
/*
* We found a redirect item that doesn't point to a valid follow-on
* item. This can happen if the loop in heap_page_prune caused us to
* visit the dead successor of a redirect item before visiting the
* redirect item. We can clean up by setting the redirect item to
* DEAD state.
*/
heap_prune_record_dead(prstate, rootoffnum);
}
else if (redirect_move && ItemIdIsRedirected(rootlp))
{
/*
* If we desire to eliminate LP_REDIRECT items by moving tuples, make
* a redirection entry for each redirected root item; this will cause
* heap_page_prune_execute to actually do the move. (We get here only
* when there are no DEAD tuples in the chain; otherwise the
* redirection entry was made above.)
*/
heap_prune_record_redirect(prstate, rootoffnum, chainitems[1]);
redirect_target = chainitems[1];
}
/*
* If we are going to implement a redirect by moving tuples, we have to
* issue a cache invalidation against the redirection target tuple,
* because its CTID will be effectively changed by the move. Note that
* CacheInvalidateHeapTuple only queues the request, it doesn't send it;
* if we fail before reaching EndNonTransactionalInvalidation, nothing
* happens and no harm is done.
*/
if (OffsetNumberIsValid(redirect_target))
{
ItemId firstlp = PageGetItemId(dp, redirect_target);
HeapTupleData firsttup;
Assert(ItemIdIsNormal(firstlp));
/* Set up firsttup to reference the tuple at its existing CTID */
firsttup.t_data = (HeapTupleHeader) PageGetItem(dp, firstlp);
firsttup.t_len = ItemIdGetLength(firstlp);
ItemPointerSet(&firsttup.t_self,
BufferGetBlockNumber(buffer),
redirect_target);
CacheInvalidateHeapTuple(relation, &firsttup);
}
return ndeleted;
}
/*
* lazy_scan_heap() -- scan an open heap relation
*
* This routine sets commit status bits, builds lists of dead tuples
* and pages with free space, and calculates statistics on the number
* of live tuples in the heap. When done, or when we run low on space
* for dead-tuple TIDs, invoke vacuuming of indexes and heap.
*
* If there are no indexes then we just vacuum each dirty page as we
* process it, since there's no point in gathering many tuples.
*/
static void
lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
Relation *Irel, int nindexes, bool scan_all)
{
BlockNumber nblocks,
blkno;
HeapTupleData tuple;
char *relname;
BlockNumber empty_pages,
vacuumed_pages;
double num_tuples,
tups_vacuumed,
nkeep,
nunused;
IndexBulkDeleteResult **indstats;
int i;
PGRUsage ru0;
Buffer vmbuffer = InvalidBuffer;
BlockNumber next_not_all_visible_block;
bool skipping_all_visible_blocks;
pg_rusage_init(&ru0);
relname = RelationGetRelationName(onerel);
ereport(elevel,
(errmsg("vacuuming \"%s.%s\"",
get_namespace_name(RelationGetNamespace(onerel)),
relname)));
empty_pages = vacuumed_pages = 0;
num_tuples = tups_vacuumed = nkeep = nunused = 0;
indstats = (IndexBulkDeleteResult **)
palloc0(nindexes * sizeof(IndexBulkDeleteResult *));
nblocks = RelationGetNumberOfBlocks(onerel);
vacrelstats->rel_pages = nblocks;
vacrelstats->scanned_pages = 0;
vacrelstats->nonempty_pages = 0;
vacrelstats->latestRemovedXid = InvalidTransactionId;
lazy_space_alloc(vacrelstats, nblocks);
/*
* We want to skip pages that don't require vacuuming according to the
* visibility map, but only when we can skip at least SKIP_PAGES_THRESHOLD
* consecutive pages. Since we're reading sequentially, the OS should be
* doing readahead for us, so there's no gain in skipping a page now and
* then; that's likely to disable readahead and so be counterproductive.
* Also, skipping even a single page means that we can't update
* relfrozenxid, so we only want to do it if we can skip a goodly number
* of pages.
*
* Before entering the main loop, establish the invariant that
* next_not_all_visible_block is the next block number >= blkno that's not
* all-visible according to the visibility map, or nblocks if there's no
* such block. Also, we set up the skipping_all_visible_blocks flag,
* which is needed because we need hysteresis in the decision: once we've
* started skipping blocks, we may as well skip everything up to the next
* not-all-visible block.
*
* Note: if scan_all is true, we won't actually skip any pages; but we
* maintain next_not_all_visible_block anyway, so as to set up the
* all_visible_according_to_vm flag correctly for each page.
*/
for (next_not_all_visible_block = 0;
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
if (!visibilitymap_test(onerel, next_not_all_visible_block, &vmbuffer))
break;
vacuum_delay_point();
}
if (next_not_all_visible_block >= SKIP_PAGES_THRESHOLD)
skipping_all_visible_blocks = true;
else
skipping_all_visible_blocks = false;
for (blkno = 0; blkno < nblocks; blkno++)
{
Buffer buf;
Page page;
OffsetNumber offnum,
maxoff;
bool tupgone,
hastup;
int prev_dead_count;
OffsetNumber frozen[MaxOffsetNumber];
int nfrozen;
Size freespace;
bool all_visible_according_to_vm;
bool all_visible;
bool has_dead_tuples;
if (blkno == next_not_all_visible_block)
{
/* Time to advance next_not_all_visible_block */
for (next_not_all_visible_block++;
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
if (!visibilitymap_test(onerel, next_not_all_visible_block,
&vmbuffer))
break;
vacuum_delay_point();
}
/*
* We know we can't skip the current block. But set up
* skipping_all_visible_blocks to do the right thing at the
* following blocks.
*/
if (next_not_all_visible_block - blkno > SKIP_PAGES_THRESHOLD)
skipping_all_visible_blocks = true;
else
skipping_all_visible_blocks = false;
all_visible_according_to_vm = false;
}
else
{
/* Current block is all-visible */
if (skipping_all_visible_blocks && !scan_all)
continue;
all_visible_according_to_vm = true;
}
vacuum_delay_point();
vacrelstats->scanned_pages++;
/*
* If we are close to overrunning the available space for dead-tuple
* TIDs, pause and do a cycle of vacuuming before we tackle this page.
*/
if ((vacrelstats->max_dead_tuples - vacrelstats->num_dead_tuples) < MaxHeapTuplesPerPage &&
vacrelstats->num_dead_tuples > 0)
{
/* Log cleanup info before we touch indexes */
vacuum_log_cleanup_info(onerel, vacrelstats);
/* Remove index entries */
for (i = 0; i < nindexes; i++)
lazy_vacuum_index(Irel[i],
&indstats[i],
vacrelstats);
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
/*
* Forget the now-vacuumed tuples, and press on, but be careful
* not to reset latestRemovedXid since we want that value to be
* valid.
*/
vacrelstats->num_dead_tuples = 0;
vacrelstats->num_index_scans++;
}
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
RBM_NORMAL, vac_strategy);
/* We need buffer cleanup lock so that we can prune HOT chains. */
LockBufferForCleanup(buf);
page = BufferGetPage(buf);
if (PageIsNew(page))
{
/*
* An all-zeroes page could be left over if a backend extends the
* relation but crashes before initializing the page. Reclaim such
* pages for use.
*
* We have to be careful here because we could be looking at a
* page that someone has just added to the relation and not yet
* been able to initialize (see RelationGetBufferForTuple). To
* protect against that, release the buffer lock, grab the
* relation extension lock momentarily, and re-lock the buffer. If
* the page is still uninitialized by then, it must be left over
* from a crashed backend, and we can initialize it.
*
* We don't really need the relation lock when this is a new or
* temp relation, but it's probably not worth the code space to
* check that, since this surely isn't a critical path.
*
* Note: the comparable code in vacuum.c need not worry because
* it's got exclusive lock on the whole relation.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockRelationForExtension(onerel, ExclusiveLock);
UnlockRelationForExtension(onerel, ExclusiveLock);
LockBufferForCleanup(buf);
if (PageIsNew(page))
{
ereport(WARNING,
(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
relname, blkno)));
PageInit(page, BufferGetPageSize(buf), 0);
empty_pages++;
}
freespace = PageGetHeapFreeSpace(page);
MarkBufferDirty(buf);
UnlockReleaseBuffer(buf);
RecordPageWithFreeSpace(onerel, blkno, freespace);
continue;
}
if (PageIsEmpty(page))
{
empty_pages++;
freespace = PageGetHeapFreeSpace(page);
if (!PageIsAllVisible(page))
{
PageSetAllVisible(page);
SetBufferCommitInfoNeedsSave(buf);
}
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/* Update the visibility map */
if (!all_visible_according_to_vm)
{
visibilitymap_pin(onerel, blkno, &vmbuffer);
LockBuffer(buf, BUFFER_LOCK_SHARE);
if (PageIsAllVisible(page))
visibilitymap_set(onerel, blkno, PageGetLSN(page), &vmbuffer);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
ReleaseBuffer(buf);
RecordPageWithFreeSpace(onerel, blkno, freespace);
continue;
}
/*
* Prune all HOT-update chains in this page.
*
* We count tuples removed by the pruning step as removed by VACUUM.
*/
tups_vacuumed += heap_page_prune(onerel, buf, OldestXmin, false,
&vacrelstats->latestRemovedXid);
/*
* Now scan the page to collect vacuumable items and check for tuples
* requiring freezing.
*/
all_visible = true;
has_dead_tuples = false;
nfrozen = 0;
hastup = false;
prev_dead_count = vacrelstats->num_dead_tuples;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
itemid = PageGetItemId(page, offnum);
/* Unused items require no processing, but we count 'em */
if (!ItemIdIsUsed(itemid))
{
nunused += 1;
continue;
}
/* Redirect items mustn't be touched */
if (ItemIdIsRedirected(itemid))
{
hastup = true; /* this page won't be truncatable */
continue;
}
ItemPointerSet(&(tuple.t_self), blkno, offnum);
/*
* DEAD item pointers are to be vacuumed normally; but we don't
* count them in tups_vacuumed, else we'd be double-counting (at
* least in the common case where heap_page_prune() just freed up
* a non-HOT tuple).
*/
if (ItemIdIsDead(itemid))
{
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
all_visible = false;
continue;
}
Assert(ItemIdIsNormal(itemid));
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple.t_len = ItemIdGetLength(itemid);
tupgone = false;
switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
{
case HEAPTUPLE_DEAD:
/*
* Ordinarily, DEAD tuples would have been removed by
* heap_page_prune(), but it's possible that the tuple
* state changed since heap_page_prune() looked. In
* particular an INSERT_IN_PROGRESS tuple could have
* changed to DEAD if the inserter aborted. So this
* cannot be considered an error condition.
*
* If the tuple is HOT-updated then it must only be
* removed by a prune operation; so we keep it just as if
* it were RECENTLY_DEAD. Also, if it's a heap-only
* tuple, we choose to keep it, because it'll be a lot
* cheaper to get rid of it in the next pruning pass than
* to treat it like an indexed tuple.
*/
if (HeapTupleIsHotUpdated(&tuple) ||
HeapTupleIsHeapOnly(&tuple))
nkeep += 1;
else
tupgone = true; /* we can delete the tuple */
all_visible = false;
break;
case HEAPTUPLE_LIVE:
/* Tuple is good --- but let's do some validity checks */
if (onerel->rd_rel->relhasoids &&
!OidIsValid(HeapTupleGetOid(&tuple)))
elog(WARNING, "relation \"%s\" TID %u/%u: OID is invalid",
relname, blkno, offnum);
/*
* Is the tuple definitely visible to all transactions?
*
* NB: Like with per-tuple hint bits, we can't set the
* PD_ALL_VISIBLE flag if the inserter committed
* asynchronously. See SetHintBits for more info. Check
* that the HEAP_XMIN_COMMITTED hint bit is set because of
* that.
*/
if (all_visible)
{
TransactionId xmin;
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
all_visible = false;
break;
}
/*
* The inserter definitely committed. But is it old
* enough that everyone sees it as committed?
*/
xmin = HeapTupleHeaderGetXmin(tuple.t_data);
if (!TransactionIdPrecedes(xmin, OldestXmin))
{
all_visible = false;
break;
}
}
break;
case HEAPTUPLE_RECENTLY_DEAD:
/*
* If tuple is recently deleted then we must not remove it
* from relation.
*/
nkeep += 1;
all_visible = false;
break;
case HEAPTUPLE_INSERT_IN_PROGRESS:
/* This is an expected case during concurrent vacuum */
all_visible = false;
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
/* This is an expected case during concurrent vacuum */
all_visible = false;
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
if (tupgone)
{
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
HeapTupleHeaderAdvanceLatestRemovedXid(tuple.t_data,
&vacrelstats->latestRemovedXid);
tups_vacuumed += 1;
has_dead_tuples = true;
}
else
{
num_tuples += 1;
hastup = true;
/*
* Each non-removable tuple must be checked to see if it needs
* freezing. Note we already have exclusive buffer lock.
*/
if (heap_freeze_tuple(tuple.t_data, FreezeLimit,
InvalidBuffer))
frozen[nfrozen++] = offnum;
}
} /* scan along page */
/*
* If we froze any tuples, mark the buffer dirty, and write a WAL
* record recording the changes. We must log the changes to be
* crash-safe against future truncation of CLOG.
*/
if (nfrozen > 0)
{
MarkBufferDirty(buf);
if (RelationNeedsWAL(onerel))
{
XLogRecPtr recptr;
recptr = log_heap_freeze(onerel, buf, FreezeLimit,
frozen, nfrozen);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
}
/*
* If there are no indexes then we can vacuum the page right now
* instead of doing a second scan.
*/
if (nindexes == 0 &&
vacrelstats->num_dead_tuples > 0)
{
/* Remove tuples from heap */
lazy_vacuum_page(onerel, blkno, buf, 0, vacrelstats);
/*
* Forget the now-vacuumed tuples, and press on, but be careful
* not to reset latestRemovedXid since we want that value to be
* valid.
*/
vacrelstats->num_dead_tuples = 0;
vacuumed_pages++;
}
freespace = PageGetHeapFreeSpace(page);
/* Update the all-visible flag on the page */
if (!PageIsAllVisible(page) && all_visible)
{
PageSetAllVisible(page);
SetBufferCommitInfoNeedsSave(buf);
}
/*
* It's possible for the value returned by GetOldestXmin() to move
* backwards, so it's not wrong for us to see tuples that appear to
* not be visible to everyone yet, while PD_ALL_VISIBLE is already
* set. The real safe xmin value never moves backwards, but
* GetOldestXmin() is conservative and sometimes returns a value
* that's unnecessarily small, so if we see that contradiction it just
* means that the tuples that we think are not visible to everyone yet
* actually are, and the PD_ALL_VISIBLE flag is correct.
*
* There should never be dead tuples on a page with PD_ALL_VISIBLE
* set, however.
*/
else if (PageIsAllVisible(page) && has_dead_tuples)
{
elog(WARNING, "page containing dead tuples is marked as all-visible in relation \"%s\" page %u",
relname, blkno);
PageClearAllVisible(page);
SetBufferCommitInfoNeedsSave(buf);
/*
* Normally, we would drop the lock on the heap page before
* updating the visibility map, but since this case shouldn't
* happen anyway, don't worry about that.
*/
visibilitymap_clear(onerel, blkno);
}
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/* Update the visibility map */
if (!all_visible_according_to_vm && all_visible)
{
visibilitymap_pin(onerel, blkno, &vmbuffer);
LockBuffer(buf, BUFFER_LOCK_SHARE);
if (PageIsAllVisible(page))
visibilitymap_set(onerel, blkno, PageGetLSN(page), &vmbuffer);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
ReleaseBuffer(buf);
/* Remember the location of the last page with nonremovable tuples */
if (hastup)
vacrelstats->nonempty_pages = blkno + 1;
/*
* If we remembered any tuples for deletion, then the page will be
* visited again by lazy_vacuum_heap, which will compute and record
* its post-compaction free space. If not, then we're done with this
* page, so remember its free space as-is. (This path will always be
* taken if there are no indexes.)
*/
if (vacrelstats->num_dead_tuples == prev_dead_count)
RecordPageWithFreeSpace(onerel, blkno, freespace);
}
/* save stats for use later */
vacrelstats->scanned_tuples = num_tuples;
vacrelstats->tuples_deleted = tups_vacuumed;
/* now we can compute the new value for pg_class.reltuples */
vacrelstats->new_rel_tuples = vac_estimate_reltuples(onerel, false,
nblocks,
vacrelstats->scanned_pages,
num_tuples);
/* If any tuples need to be deleted, perform final vacuum cycle */
/* XXX put a threshold on min number of tuples here? */
if (vacrelstats->num_dead_tuples > 0)
{
/* Log cleanup info before we touch indexes */
vacuum_log_cleanup_info(onerel, vacrelstats);
/* Remove index entries */
for (i = 0; i < nindexes; i++)
lazy_vacuum_index(Irel[i],
&indstats[i],
vacrelstats);
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
vacrelstats->num_index_scans++;
}
/* Release the pin on the visibility map page */
if (BufferIsValid(vmbuffer))
{
ReleaseBuffer(vmbuffer);
vmbuffer = InvalidBuffer;
}
/* Do post-vacuum cleanup and statistics update for each index */
for (i = 0; i < nindexes; i++)
lazy_cleanup_index(Irel[i], indstats[i], vacrelstats);
/* If no indexes, make log report that lazy_vacuum_heap would've made */
if (vacuumed_pages)
ereport(elevel,
(errmsg("\"%s\": removed %.0f row versions in %u pages",
RelationGetRelationName(onerel),
tups_vacuumed, vacuumed_pages)));
ereport(elevel,
(errmsg("\"%s\": found %.0f removable, %.0f nonremovable row versions in %u out of %u pages",
RelationGetRelationName(onerel),
tups_vacuumed, num_tuples,
vacrelstats->scanned_pages, nblocks),
errdetail("%.0f dead row versions cannot be removed yet.\n"
"There were %.0f unused item pointers.\n"
"%u pages are entirely empty.\n"
"%s.",
nkeep,
nunused,
empty_pages,
pg_rusage_show(&ru0))));
}
/*
* For all items in this page, find their respective root line pointers.
* If item k is part of a HOT-chain with root at item j, then we set
* root_offsets[k - 1] = j.
*
* The passed-in root_offsets array must have MaxHeapTuplesPerPage entries.
* We zero out all unused entries.
*
* The function must be called with at least share lock on the buffer, to
* prevent concurrent prune operations.
*
* Note: The information collected here is valid only as long as the caller
* holds a pin on the buffer. Once pin is released, a tuple might be pruned
* and reused by a completely unrelated tuple.
*/
void
heap_get_root_tuples(Page page, OffsetNumber *root_offsets)
{
OffsetNumber offnum,
maxoff;
MemSet(root_offsets, 0, MaxHeapTuplesPerPage * sizeof(OffsetNumber));
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber; offnum <= maxoff; offnum = OffsetNumberNext(offnum))
{
ItemId lp = PageGetItemId(page, offnum);
HeapTupleHeader htup;
OffsetNumber nextoffnum;
TransactionId priorXmax;
/* skip unused and dead items */
if (!ItemIdIsUsed(lp) || ItemIdIsDead(lp))
continue;
if (ItemIdIsNormal(lp))
{
htup = (HeapTupleHeader) PageGetItem(page, lp);
/*
* Check if this tuple is part of a HOT-chain rooted at some other
* tuple. If so, skip it for now; we'll process it when we find
* its root.
*/
if (HeapTupleHeaderIsHeapOnly(htup))
continue;
/*
* This is either a plain tuple or the root of a HOT-chain.
* Remember it in the mapping.
*/
root_offsets[offnum - 1] = offnum;
/* If it's not the start of a HOT-chain, we're done with it */
if (!HeapTupleHeaderIsHotUpdated(htup))
continue;
/* Set up to scan the HOT-chain */
nextoffnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
priorXmax = HeapTupleHeaderGetXmax(htup);
}
else
{
/* Must be a redirect item. We do not set its root_offsets entry */
Assert(ItemIdIsRedirected(lp));
/* Set up to scan the HOT-chain */
nextoffnum = ItemIdGetRedirect(lp);
priorXmax = InvalidTransactionId;
}
/*
* Now follow the HOT-chain and collect other tuples in the chain.
*
* Note: Even though this is a nested loop, the complexity of the
* function is O(N) because a tuple in the page should be visited not
* more than twice, once in the outer loop and once in HOT-chain
* chases.
*/
for (;;)
{
lp = PageGetItemId(page, nextoffnum);
/* Check for broken chains */
if (!ItemIdIsNormal(lp))
break;
htup = (HeapTupleHeader) PageGetItem(page, lp);
if (TransactionIdIsValid(priorXmax) &&
!TransactionIdEquals(priorXmax, HeapTupleHeaderGetXmin(htup)))
break;
/* Remember the root line pointer for this item */
root_offsets[nextoffnum - 1] = offnum;
/* Advance to next chain member, if any */
if (!HeapTupleHeaderIsHotUpdated(htup))
break;
nextoffnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
priorXmax = HeapTupleHeaderGetXmax(htup);
}
}
}
