diff options
Diffstat (limited to 'src/backend/access/heap/heapam_handler.c')
| -rw-r--r-- | src/backend/access/heap/heapam_handler.c | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index 6a26fcef94c..fcd4acb5aa3 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -21,7 +21,9 @@ #include "access/heapam.h" #include "access/tableam.h" +#include "access/xact.h" #include "storage/bufmgr.h" +#include "storage/lmgr.h" #include "utils/builtins.h" @@ -169,6 +171,321 @@ heapam_tuple_satisfies_snapshot(Relation rel, TupleTableSlot *slot, } +/* ---------------------------------------------------------------------------- + * Functions for manipulations of physical tuples for heap AM. + * ---------------------------------------------------------------------------- + */ + +static void +heapam_tuple_insert(Relation relation, TupleTableSlot *slot, CommandId cid, + int options, BulkInsertState bistate) +{ + bool shouldFree = true; + HeapTuple tuple = ExecFetchSlotHeapTuple(slot, true, &shouldFree); + + /* Update the tuple with table oid */ + slot->tts_tableOid = RelationGetRelid(relation); + tuple->t_tableOid = slot->tts_tableOid; + + /* Perform the insertion, and copy the resulting ItemPointer */ + heap_insert(relation, tuple, cid, options, bistate); + ItemPointerCopy(&tuple->t_self, &slot->tts_tid); + + if (shouldFree) + pfree(tuple); +} + +static void +heapam_tuple_insert_speculative(Relation relation, TupleTableSlot *slot, CommandId cid, + int options, BulkInsertState bistate, uint32 specToken) +{ + bool shouldFree = true; + HeapTuple tuple = ExecFetchSlotHeapTuple(slot, true, &shouldFree); + + /* Update the tuple with table oid */ + slot->tts_tableOid = RelationGetRelid(relation); + tuple->t_tableOid = slot->tts_tableOid; + + HeapTupleHeaderSetSpeculativeToken(tuple->t_data, specToken); + options |= HEAP_INSERT_SPECULATIVE; + + /* Perform the insertion, and copy the resulting ItemPointer */ + heap_insert(relation, tuple, cid, options, bistate); + ItemPointerCopy(&tuple->t_self, &slot->tts_tid); + + if (shouldFree) + pfree(tuple); +} + +static void +heapam_tuple_complete_speculative(Relation relation, TupleTableSlot *slot, uint32 spekToken, + bool succeeded) +{ + bool shouldFree = true; + HeapTuple tuple = ExecFetchSlotHeapTuple(slot, true, &shouldFree); + + /* adjust the tuple's state accordingly */ + if (!succeeded) + heap_finish_speculative(relation, &slot->tts_tid); + else + heap_abort_speculative(relation, &slot->tts_tid); + + if (shouldFree) + pfree(tuple); +} + +static TM_Result +heapam_tuple_delete(Relation relation, ItemPointer tid, CommandId cid, + Snapshot snapshot, Snapshot crosscheck, bool wait, + TM_FailureData *tmfd, bool changingPart) +{ + /* + * Currently Deleting of index tuples are handled at vacuum, in case if + * the storage itself is cleaning the dead tuples by itself, it is the + * time to call the index tuple deletion also. + */ + return heap_delete(relation, tid, cid, crosscheck, wait, tmfd, changingPart); +} + + +static TM_Result +heapam_tuple_update(Relation relation, ItemPointer otid, TupleTableSlot *slot, + CommandId cid, Snapshot snapshot, Snapshot crosscheck, + bool wait, TM_FailureData *tmfd, + LockTupleMode *lockmode, bool *update_indexes) +{ + bool shouldFree = true; + HeapTuple tuple = ExecFetchSlotHeapTuple(slot, true, &shouldFree); + TM_Result result; + + /* Update the tuple with table oid */ + slot->tts_tableOid = RelationGetRelid(relation); + tuple->t_tableOid = slot->tts_tableOid; + + result = heap_update(relation, otid, tuple, cid, crosscheck, wait, + tmfd, lockmode); + ItemPointerCopy(&tuple->t_self, &slot->tts_tid); + + /* + * Decide whether new index entries are needed for the tuple + * + * Note: heap_update returns the tid (location) of the new tuple in the + * t_self field. + * + * If it's a HOT update, we mustn't insert new index entries. + */ + *update_indexes = result == TM_Ok && !HeapTupleIsHeapOnly(tuple); + + if (shouldFree) + pfree(tuple); + + return result; +} + +static TM_Result +heapam_tuple_lock(Relation relation, ItemPointer tid, Snapshot snapshot, + TupleTableSlot *slot, CommandId cid, LockTupleMode mode, + LockWaitPolicy wait_policy, uint8 flags, + TM_FailureData *tmfd) +{ + BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot; + TM_Result result; + Buffer buffer; + HeapTuple tuple = &bslot->base.tupdata; + bool follow_updates; + + follow_updates = (flags & TUPLE_LOCK_FLAG_LOCK_UPDATE_IN_PROGRESS) != 0; + tmfd->traversed = false; + + Assert(TTS_IS_BUFFERTUPLE(slot)); + +tuple_lock_retry: + tuple->t_self = *tid; + result = heap_lock_tuple(relation, tuple, cid, mode, wait_policy, + follow_updates, &buffer, tmfd); + + if (result == TM_Updated && + (flags & TUPLE_LOCK_FLAG_FIND_LAST_VERSION)) + { + ReleaseBuffer(buffer); + /* Should not encounter speculative tuple on recheck */ + Assert(!HeapTupleHeaderIsSpeculative(tuple->t_data)); + + if (!ItemPointerEquals(&tmfd->ctid, &tuple->t_self)) + { + SnapshotData SnapshotDirty; + TransactionId priorXmax; + + /* it was updated, so look at the updated version */ + *tid = tmfd->ctid; + /* updated row should have xmin matching this xmax */ + priorXmax = tmfd->xmax; + + /* signal that a tuple later in the chain is getting locked */ + tmfd->traversed = true; + + /* + * fetch target tuple + * + * Loop here to deal with updated or busy tuples + */ + InitDirtySnapshot(SnapshotDirty); + for (;;) + { + if (ItemPointerIndicatesMovedPartitions(tid)) + ereport(ERROR, + (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE), + errmsg("tuple to be locked was already moved to another partition due to concurrent update"))); + + tuple->t_self = *tid; + if (heap_fetch(relation, &SnapshotDirty, tuple, &buffer, NULL)) + { + /* + * If xmin isn't what we're expecting, the slot must have + * been recycled and reused for an unrelated tuple. This + * implies that the latest version of the row was deleted, + * so we need do nothing. (Should be safe to examine xmin + * without getting buffer's content lock. We assume + * reading a TransactionId to be atomic, and Xmin never + * changes in an existing tuple, except to invalid or + * frozen, and neither of those can match priorXmax.) + */ + if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple->t_data), + priorXmax)) + { + ReleaseBuffer(buffer); + return TM_Deleted; + } + + /* otherwise xmin should not be dirty... */ + if (TransactionIdIsValid(SnapshotDirty.xmin)) + elog(ERROR, "t_xmin is uncommitted in tuple to be updated"); + + /* + * If tuple is being updated by other transaction then we + * have to wait for its commit/abort, or die trying. + */ + if (TransactionIdIsValid(SnapshotDirty.xmax)) + { + ReleaseBuffer(buffer); + switch (wait_policy) + { + case LockWaitBlock: + XactLockTableWait(SnapshotDirty.xmax, + relation, &tuple->t_self, + XLTW_FetchUpdated); + break; + case LockWaitSkip: + if (!ConditionalXactLockTableWait(SnapshotDirty.xmax)) + /* skip instead of waiting */ + return TM_WouldBlock; + break; + case LockWaitError: + if (!ConditionalXactLockTableWait(SnapshotDirty.xmax)) + ereport(ERROR, + (errcode(ERRCODE_LOCK_NOT_AVAILABLE), + errmsg("could not obtain lock on row in relation \"%s\"", + RelationGetRelationName(relation)))); + break; + } + continue; /* loop back to repeat heap_fetch */ + } + + /* + * If tuple was inserted by our own transaction, we have + * to check cmin against cid: cmin >= current CID means + * our command cannot see the tuple, so we should ignore + * it. Otherwise heap_lock_tuple() will throw an error, + * and so would any later attempt to update or delete the + * tuple. (We need not check cmax because + * HeapTupleSatisfiesDirty will consider a tuple deleted + * by our transaction dead, regardless of cmax.) We just + * checked that priorXmax == xmin, so we can test that + * variable instead of doing HeapTupleHeaderGetXmin again. + */ + if (TransactionIdIsCurrentTransactionId(priorXmax) && + HeapTupleHeaderGetCmin(tuple->t_data) >= cid) + { + ReleaseBuffer(buffer); + return TM_Invisible; + } + + /* + * This is a live tuple, so try to lock it again. + */ + ReleaseBuffer(buffer); + goto tuple_lock_retry; + } + + /* + * If the referenced slot was actually empty, the latest + * version of the row must have been deleted, so we need do + * nothing. + */ + if (tuple->t_data == NULL) + { + return TM_Deleted; + } + + /* + * As above, if xmin isn't what we're expecting, do nothing. + */ + if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple->t_data), + priorXmax)) + { + if (BufferIsValid(buffer)) + ReleaseBuffer(buffer); + return TM_Deleted; + } + + /* + * If we get here, the tuple was found but failed + * SnapshotDirty. Assuming the xmin is either a committed xact + * or our own xact (as it certainly should be if we're trying + * to modify the tuple), this must mean that the row was + * updated or deleted by either a committed xact or our own + * xact. If it was deleted, we can ignore it; if it was + * updated then chain up to the next version and repeat the + * whole process. + * + * As above, it should be safe to examine xmax and t_ctid + * without the buffer content lock, because they can't be + * changing. + */ + if (ItemPointerEquals(&tuple->t_self, &tuple->t_data->t_ctid)) + { + /* deleted, so forget about it */ + if (BufferIsValid(buffer)) + ReleaseBuffer(buffer); + return TM_Deleted; + } + + /* updated, so look at the updated row */ + *tid = tuple->t_data->t_ctid; + /* updated row should have xmin matching this xmax */ + priorXmax = HeapTupleHeaderGetUpdateXid(tuple->t_data); + if (BufferIsValid(buffer)) + ReleaseBuffer(buffer); + /* loop back to fetch next in chain */ + } + } + else + { + /* tuple was deleted, so give up */ + return TM_Deleted; + } + } + + slot->tts_tableOid = RelationGetRelid(relation); + tuple->t_tableOid = slot->tts_tableOid; + + /* store in slot, transferring existing pin */ + ExecStorePinnedBufferHeapTuple(tuple, slot, buffer); + + return result; +} + + /* ------------------------------------------------------------------------ * Definition of the heap table access method. * ------------------------------------------------------------------------ @@ -193,6 +510,13 @@ static const TableAmRoutine heapam_methods = { .index_fetch_end = heapam_index_fetch_end, .index_fetch_tuple = heapam_index_fetch_tuple, + .tuple_insert = heapam_tuple_insert, + .tuple_insert_speculative = heapam_tuple_insert_speculative, + .tuple_complete_speculative = heapam_tuple_complete_speculative, + .tuple_delete = heapam_tuple_delete, + .tuple_update = heapam_tuple_update, + .tuple_lock = heapam_tuple_lock, + .tuple_satisfies_snapshot = heapam_tuple_satisfies_snapshot, }; |