diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index c435482cd21..0c0f640f640 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -2598,15 +2598,17 @@ heap_prepare_insert(Relation relation, HeapTuple tup, TransactionId xid, CommandId cid, int options) { /* - * For now, parallel operations are required to be strictly read-only. - * Unlike heap_update() and heap_delete(), an insert should never create a - * combo CID, so it might be possible to relax this restriction, but not - * without more thought and testing. - */ - if (IsInParallelMode()) + * Parallel operations are required to be strictly read-only in a parallel + * worker. Parallel inserts are not safe even in the leader in the + * general case, because group locking means that heavyweight locks for + * relation extension or GIN page locks will not conflict between members + * of a lock group, but we don't prohibit that case here because there are + * useful special cases that we can safely allow, such as CREATE TABLE AS. + */ + if (IsParallelWorker()) ereport(ERROR, (errcode(ERRCODE_INVALID_TRANSACTION_STATE), - errmsg("cannot insert tuples during a parallel operation"))); + errmsg("cannot insert tuples in a parallel worker"))); if (relation->rd_rel->relhasoids) { |