/* ----------------------------------------------------------------
* ExecUpdate
*
* note: we can't run UPDATE queries with transactions
* off because UPDATEs are actually INSERTs and our
* scan will mistakenly loop forever, updating the tuple
* it just inserted.. This should be fixed but until it
* is, we don't want to get stuck in an infinite loop
* which corrupts your database..
* ----------------------------------------------------------------
*/
void
ExecUpdate(TupleTableSlot *slot,
ItemPointer tupleid,
TupleTableSlot *planSlot,
DestReceiver *dest,
EState *estate)
{
HeapTuple tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
HTSU_Result result;
ItemPointerData update_ctid;
TransactionId update_xmax;
/*
* abort the operation if not running transactions
*/
if (IsBootstrapProcessingMode())
elog(ERROR, "cannot UPDATE during bootstrap");
/*
* get the heap tuple out of the tuple table slot, making sure we have a
* writable copy
*/
tuple = ExecFetchSlotHeapTuple(slot);
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* see if this update would move the tuple to a different partition */
if (estate->es_result_partitions)
{
AttrNumber max_attr;
Datum *values;
bool *nulls;
Oid targetid;
Assert(estate->es_partition_state != NULL &&
estate->es_partition_state->accessMethods != NULL);
if (!estate->es_partition_state->accessMethods->part_cxt)
estate->es_partition_state->accessMethods->part_cxt =
GetPerTupleExprContext(estate)->ecxt_per_tuple_memory;
Assert(PointerIsValid(estate->es_result_partitions));
max_attr = estate->es_partition_state->max_partition_attr;
slot_getsomeattrs(slot, max_attr);
values = slot_get_values(slot);
nulls = slot_get_isnull(slot);
targetid = selectPartition(estate->es_result_partitions, values,
nulls, slot->tts_tupleDescriptor,
estate->es_partition_state->accessMethods);
if (!OidIsValid(targetid))
ereport(ERROR,
(errcode(ERRCODE_NO_PARTITION_FOR_PARTITIONING_KEY),
errmsg("no partition for partitioning key")));
if (RelationGetRelid(resultRelationDesc) != targetid)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("moving tuple from partition \"%s\" to "
"partition \"%s\" not supported",
get_rel_name(RelationGetRelid(resultRelationDesc)),
get_rel_name(targetid)),
errOmitLocation(true)));
}
}
/* BEFORE ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
tupleid, tuple,
estate->es_snapshot->curcid);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
/*
* Put the modified tuple into a slot for convenience of routines
* below. We assume the tuple was allocated in per-tuple memory
* context, and therefore will go away by itself. The tuple table
* slot should not try to clear it.
*/
TupleTableSlot *newslot = estate->es_trig_tuple_slot;
if (newslot->tts_tupleDescriptor != slot->tts_tupleDescriptor)
ExecSetSlotDescriptor(newslot, slot->tts_tupleDescriptor);
ExecStoreGenericTuple(newtuple, newslot, false);
newslot->tts_tableOid = slot->tts_tableOid; /* for constraints */
slot = newslot;
tuple = newtuple;
}
}
/*
* Check the constraints of the tuple
*
* If we generate a new candidate tuple after EvalPlanQual testing, we
* must loop back here and recheck constraints. (We don't need to redo
* triggers, however. If there are any BEFORE triggers then trigger.c
* will have done heap_lock_tuple to lock the correct tuple, so there's no
* need to do them again.)
*/
lreplace:;
if (resultRelationDesc->rd_att->constr)
ExecConstraints(resultRelInfo, slot, estate);
if (!GpPersistent_IsPersistentRelation(resultRelationDesc->rd_id))
{
/*
* Normal UPDATE path.
*/
/*
* replace the heap tuple
*
* Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
* the row to be updated is visible to that snapshot, and throw a can't-
* serialize error if not. This is a special-case behavior needed for
* referential integrity updates in serializable transactions.
*/
result = heap_update(resultRelationDesc, tupleid, tuple,
&update_ctid, &update_xmax,
estate->es_snapshot->curcid,
estate->es_crosscheck_snapshot,
true /* wait for commit */ );
switch (result)
{
case HeapTupleSelfUpdated:
/* already deleted by self; nothing to do */
return;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (IsXactIsoLevelSerializable)
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
else if (!ItemPointerEquals(tupleid, &update_ctid))
{
TupleTableSlot *epqslot;
epqslot = EvalPlanQual(estate,
resultRelInfo->ri_RangeTableIndex,
&update_ctid,
update_xmax,
estate->es_snapshot->curcid);
if (!TupIsNull(epqslot))
{
*tupleid = update_ctid;
slot = ExecFilterJunk(estate->es_junkFilter, epqslot);
tuple = ExecFetchSlotHeapTuple(slot);
goto lreplace;
}
}
/* tuple already deleted; nothing to do */
return;
default:
elog(ERROR, "unrecognized heap_update status: %u", result);
return;
}
}
else
{
HeapTuple persistentTuple;
/*
* Persistent metadata path.
*/
persistentTuple = heap_copytuple(tuple);
persistentTuple->t_self = *tupleid;
frozen_heap_inplace_update(resultRelationDesc, persistentTuple);
heap_freetuple(persistentTuple);
}
IncrReplaced();
(estate->es_processed)++;
/*
* Note: instead of having to update the old index tuples associated with
* the heap tuple, all we do is form and insert new index tuples. This is
* because UPDATEs are actually DELETEs and INSERTs, and index tuple
* deletion is done later by VACUUM (see notes in ExecDelete). All we do
* here is insert new index tuples. -cim 9/27/89
*/
/*
* insert index entries for tuple
*
* Note: heap_update returns the tid (location) of the new tuple in the
* t_self field.
*/
if (resultRelInfo->ri_NumIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
/* AFTER ROW UPDATE Triggers */
ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
}
/*
* lazy_truncate_heap - try to truncate off any empty pages at the end
*/
static void
lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
{
BlockNumber old_rel_pages = vacrelstats->rel_pages;
BlockNumber new_rel_pages;
PageFreeSpaceInfo *pageSpaces;
int n;
int i,
j;
PGRUsage ru0;
/*
* Persistent table TIDs are stored in other locations like gp_relation_node
* and changeTracking logs, which continue to have references to CTID even
* if PT tuple is marked deleted. This TID is used to read tuple during
* crash recovery or segment resyncs. Hence need to avoid truncating
* persistent tables to avoid error / crash in heap_fetch using the TID
* on lazy vacuum.
*/
if (GpPersistent_IsPersistentRelation(RelationGetRelid(onerel)))
return;
pg_rusage_init(&ru0);
/*
* We need full exclusive lock on the relation in order to do truncation.
* If we can't get it, give up rather than waiting --- we don't want to
* block other backends, and we don't want to deadlock (which is quite
* possible considering we already hold a lower-grade lock).
*/
if (!ConditionalLockRelation(onerel, AccessExclusiveLock))
return;
/*
* Now that we have exclusive lock, look to see if the rel has grown
* whilst we were vacuuming with non-exclusive lock. If so, give up; the
* newly added pages presumably contain non-deletable tuples.
*/
new_rel_pages = RelationGetNumberOfBlocks(onerel);
if (new_rel_pages != old_rel_pages)
{
/* might as well use the latest news when we update pg_class stats */
vacrelstats->rel_pages = new_rel_pages;
UnlockRelation(onerel, AccessExclusiveLock);
return;
}
/*
* Scan backwards from the end to verify that the end pages actually
* contain no tuples. This is *necessary*, not optional, because other
* backends could have added tuples to these pages whilst we were
* vacuuming.
*/
new_rel_pages = count_nondeletable_pages(onerel, vacrelstats);
if (new_rel_pages >= old_rel_pages)
{
/* can't do anything after all */
UnlockRelation(onerel, AccessExclusiveLock);
return;
}
/*
* Okay to truncate.
*/
RelationTruncate(
onerel,
new_rel_pages,
/* markPersistentAsPhysicallyTruncated */ true);
/*
* Note: once we have truncated, we *must* keep the exclusive lock until
* commit. The sinval message that will be sent at commit (as a result of
* vac_update_relstats()) must be received by other backends, to cause
* them to reset their rd_targblock values, before they can safely access
* the table again.
*/
/*
* Drop free-space info for removed blocks; these must not get entered
* into the FSM!
*/
pageSpaces = vacrelstats->free_pages;
n = vacrelstats->num_free_pages;
j = 0;
for (i = 0; i < n; i++)
{
if (pageSpaces[i].blkno < new_rel_pages)
{
pageSpaces[j] = pageSpaces[i];
j++;
}
}
vacrelstats->num_free_pages = j;
/*
* If tot_free_pages was more than num_free_pages, we can't tell for sure
* what its correct value is now, because we don't know which of the
* forgotten pages are getting truncated. Conservatively set it equal to
* num_free_pages.
*/
vacrelstats->tot_free_pages = j;
/* We destroyed the heap ordering, so mark array unordered */
vacrelstats->fs_is_heap = false;
/* update statistics */
vacrelstats->rel_pages = new_rel_pages;
vacrelstats->pages_removed = old_rel_pages - new_rel_pages;
ereport(elevel,
(errmsg("\"%s\": truncated %u to %u pages",
RelationGetRelationName(onerel),
old_rel_pages, new_rel_pages),
errdetail("%s.",
pg_rusage_show(&ru0))));
}
/* ----------------------------------------------------------------
* ExecUpdate
*
* note: we can't run UPDATE queries with transactions
* off because UPDATEs are actually INSERTs and our
* scan will mistakenly loop forever, updating the tuple
* it just inserted.. This should be fixed but until it
* is, we don't want to get stuck in an infinite loop
* which corrupts your database..
* ----------------------------------------------------------------
*/
void
ExecUpdate(TupleTableSlot *slot,
ItemPointer tupleid,
TupleTableSlot *planSlot,
DestReceiver *dest,
EState *estate)
{
void* tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
HTSU_Result result;
ItemPointerData update_ctid;
TransactionId update_xmax;
AOTupleId aoTupleId = AOTUPLEID_INIT;
TupleTableSlot *partslot = NULL;
/*
* abort the operation if not running transactions
*/
if (IsBootstrapProcessingMode())
elog(ERROR, "cannot UPDATE during bootstrap");
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
bool rel_is_heap = RelationIsHeap(resultRelationDesc);
bool rel_is_aorows = RelationIsAoRows(resultRelationDesc);
bool rel_is_aocols = RelationIsAoCols(resultRelationDesc);
bool rel_is_external = RelationIsExternal(resultRelationDesc);
/*
* get the heap tuple out of the tuple table slot, making sure we have a
* writable copy
*/
if (rel_is_heap)
{
partslot = slot;
tuple = ExecFetchSlotHeapTuple(partslot);
}
else if (rel_is_aorows || rel_is_aocols)
{
/*
* It is necessary to reconstruct a logically compatible tuple to
* a phyiscally compatible tuple. The slot's tuple descriptor comes
* from the projection target list, which doesn't indicate dropped
* columns, and MemTuple cannot deal with cases without converting
* the target list back into the original relation's tuple desc.
*/
partslot = reconstructMatchingTupleSlot(slot, resultRelInfo);
/*
* We directly inline toasted columns here as update with toasted columns
* would create two references to the same toasted value.
*/
tuple = ExecFetchSlotMemTuple(partslot, true);
}
else if (rel_is_external)
{
if (estate->es_result_partitions &&
estate->es_result_partitions->part->parrelid != 0)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Update external partitions not supported.")));
return;
}
else
{
partslot = slot;
tuple = ExecFetchSlotHeapTuple(partslot);
}
}
else
{
Insist(false);
}
/* see if this update would move the tuple to a different partition */
if (estate->es_result_partitions)
checkPartitionUpdate(estate, partslot, resultRelInfo);
/* BEFORE ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
tupleid, tuple,
estate->es_snapshot->curcid);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
/*
* Put the modified tuple into a slot for convenience of routines
* below. We assume the tuple was allocated in per-tuple memory
* context, and therefore will go away by itself. The tuple table
* slot should not try to clear it.
*/
TupleTableSlot *newslot = estate->es_trig_tuple_slot;
if (newslot->tts_tupleDescriptor != partslot->tts_tupleDescriptor)
ExecSetSlotDescriptor(newslot, partslot->tts_tupleDescriptor);
ExecStoreGenericTuple(newtuple, newslot, false);
newslot->tts_tableOid = partslot->tts_tableOid; /* for constraints */
partslot = newslot;
tuple = newtuple;
}
}
/*
* Check the constraints of the tuple
*
* If we generate a new candidate tuple after EvalPlanQual testing, we
* must loop back here and recheck constraints. (We don't need to redo
* triggers, however. If there are any BEFORE triggers then trigger.c
* will have done heap_lock_tuple to lock the correct tuple, so there's no
* need to do them again.)
*/
lreplace:;
if (resultRelationDesc->rd_att->constr)
ExecConstraints(resultRelInfo, partslot, estate);
if (!GpPersistent_IsPersistentRelation(resultRelationDesc->rd_id))
{
/*
* Normal UPDATE path.
*/
/*
* replace the heap tuple
*
* Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
* the row to be updated is visible to that snapshot, and throw a can't-
* serialize error if not. This is a special-case behavior needed for
* referential integrity updates in serializable transactions.
*/
if (rel_is_heap)
{
result = heap_update(resultRelationDesc, tupleid, tuple,
&update_ctid, &update_xmax,
estate->es_snapshot->curcid,
estate->es_crosscheck_snapshot,
true /* wait for commit */ );
}
else if (rel_is_aorows)
{
if (IsXactIsoLevelSerializable)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Updates on append-only tables are not supported in serializable transactions.")));
}
if (resultRelInfo->ri_updateDesc == NULL)
{
ResultRelInfoSetSegno(resultRelInfo, estate->es_result_aosegnos);
resultRelInfo->ri_updateDesc = (AppendOnlyUpdateDesc)
appendonly_update_init(resultRelationDesc, ActiveSnapshot, resultRelInfo->ri_aosegno);
}
result = appendonly_update(resultRelInfo->ri_updateDesc,
tuple, (AOTupleId *) tupleid, &aoTupleId);
}
else if (rel_is_aocols)
{
if (IsXactIsoLevelSerializable)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Updates on append-only tables are not supported in serializable transactions.")));
}
if (resultRelInfo->ri_updateDesc == NULL)
{
ResultRelInfoSetSegno(resultRelInfo, estate->es_result_aosegnos);
resultRelInfo->ri_updateDesc = (AppendOnlyUpdateDesc)
aocs_update_init(resultRelationDesc, resultRelInfo->ri_aosegno);
}
result = aocs_update(resultRelInfo->ri_updateDesc,
partslot, (AOTupleId *) tupleid, &aoTupleId);
}
else
{
Assert(!"We should not be here");
}
switch (result)
{
case HeapTupleSelfUpdated:
/* already deleted by self; nothing to do */
return;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (IsXactIsoLevelSerializable)
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
else if (!ItemPointerEquals(tupleid, &update_ctid))
{
TupleTableSlot *epqslot;
epqslot = EvalPlanQual(estate,
resultRelInfo->ri_RangeTableIndex,
&update_ctid,
update_xmax,
estate->es_snapshot->curcid);
if (!TupIsNull(epqslot))
{
*tupleid = update_ctid;
partslot = ExecFilterJunk(estate->es_junkFilter, epqslot);
tuple = ExecFetchSlotHeapTuple(partslot);
goto lreplace;
}
}
/* tuple already deleted; nothing to do */
return;
default:
elog(ERROR, "unrecognized heap_update status: %u", result);
return;
}
}
else
{
HeapTuple persistentTuple;
/*
* Persistent metadata path.
*/
persistentTuple = heap_copytuple(tuple);
persistentTuple->t_self = *tupleid;
frozen_heap_inplace_update(resultRelationDesc, persistentTuple);
heap_freetuple(persistentTuple);
}
IncrReplaced();
(estate->es_processed)++;
(resultRelInfo->ri_aoprocessed)++;
/*
* Note: instead of having to update the old index tuples associated with
* the heap tuple, all we do is form and insert new index tuples. This is
* because UPDATEs are actually DELETEs and INSERTs, and index tuple
* deletion is done later by VACUUM (see notes in ExecDelete). All we do
* here is insert new index tuples. -cim 9/27/89
*/
/*
* insert index entries for tuple
*
* Note: heap_update returns the tid (location) of the new tuple in the
* t_self field.
*/
if (rel_is_aorows || rel_is_aocols)
{
if (resultRelInfo->ri_NumIndices > 0)
ExecInsertIndexTuples(partslot, (ItemPointer)&aoTupleId, estate, false);
}
else
{
if (resultRelInfo->ri_NumIndices > 0)
ExecInsertIndexTuples(partslot, &(((HeapTuple) tuple)->t_self), estate, false);
}
/* AFTER ROW UPDATE Triggers */
ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
}
