diff options
Diffstat (limited to 'src/backend/commands/vacuumlazy.c')
| -rw-r--r-- | src/backend/commands/vacuumlazy.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c index f525ecaf36c..8351da5e7df 100644 --- a/src/backend/commands/vacuumlazy.c +++ b/src/backend/commands/vacuumlazy.c @@ -31,7 +31,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/commands/vacuumlazy.c,v 1.5 2001/08/26 16:55:59 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/commands/vacuumlazy.c,v 1.6 2001/09/04 19:12:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -318,14 +318,21 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, /* * Tuple is good. Consider whether to replace its xmin * value with FrozenTransactionId. + * + * NB: Since we hold only a shared buffer lock here, + * we are assuming that TransactionId read/write + * is atomic. This is not the only place that makes + * such an assumption. It'd be possible to avoid the + * assumption by momentarily acquiring exclusive lock, + * but for the moment I see no need to. */ if (TransactionIdIsNormal(tuple.t_data->t_xmin) && TransactionIdPrecedes(tuple.t_data->t_xmin, FreezeLimit)) { tuple.t_data->t_xmin = FrozenTransactionId; - tuple.t_data->t_infomask &= ~HEAP_XMIN_INVALID; - tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED; + /* infomask should be okay already */ + Assert(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED); pgchanged = true; } break; |