Function RelationCreateStorage

src/backend/catalog/storage.c:124–177

* RelationCreateStorage * Create physical storage for a relation. * * Create the underlying disk file storage for the relation. This only * creates the main fork; additional forks are created lazily by the * modules that need them. * * This function is transactional. The creation is WAL-logged, and if the * transaction aborts later on, the storage will be destroyed. */

 * transaction aborts later on, the storage will be destroyed.
 */
SMgrRelation
RelationCreateStorage(RelFileNode rnode, char relpersistence, SMgrImpl smgr_which, Relation rel)
{
	PendingRelDelete *pending;
	SMgrRelation srel;
	BackendId	backend;
	bool		needs_wal;

	Assert(!IsInParallelMode());	/* couldn't update pendingSyncHash */

	switch (relpersistence)
	{
		case RELPERSISTENCE_TEMP:
			backend = BackendIdForTempRelations();
			needs_wal = false;
			break;
		case RELPERSISTENCE_UNLOGGED:
			backend = InvalidBackendId;
			needs_wal = false;
			break;
		case RELPERSISTENCE_PERMANENT:
			backend = InvalidBackendId;
			needs_wal = true;
			break;
		default:
			elog(ERROR, "invalid relpersistence: %c", relpersistence);
			return NULL;		/* placate compiler */
	}

	srel = smgropen(rnode, backend, smgr_which, rel);
	smgrcreate(srel, MAIN_FORKNUM, false);

	if (needs_wal)
		log_smgrcreate(&srel->smgr_rnode.node, MAIN_FORKNUM, smgr_which);

	/* Add the relation to the list of stuff to delete at abort */
	pending = (PendingRelDelete *)
		MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
	pending->relnode.node = rnode;
	pending->relnode.isTempRelation = backend == TempRelBackendId;
	pending->atCommit = false;	/* delete if abort */
	pending->nestLevel = GetCurrentTransactionNestLevel();
	pending->relnode.smgr_which = smgr_which;
	pending->action = &storage_pending_rel_deletes_action;
	RegisterPendingDelete(pending);

	if (relpersistence == RELPERSISTENCE_PERMANENT && !XLogIsNeeded())
	{
		Assert(backend == InvalidBackendId);
		AddPendingSync(&rnode);
	}

	return srel;
}

/*
 * Perform XLogInsert of an XLOG_SMGR_CREATE record to WAL.