Function command_delete

pg_documentdb/src/commands/delete.c:161–269

* command_delete handles a single delete on a collection. */

 * command_delete handles a single delete on a collection.
 */
Datum
command_delete(PG_FUNCTION_ARGS)
{
	if (PG_ARGISNULL(1))
	{
		ereport(ERROR, (errmsg("delete document cannot be NULL")));
	}

	Datum databaseNameDatum = PG_ARGISNULL(0) ? (Datum) 0 : PG_GETARG_DATUM(0);
	pgbson *deleteSpec = PG_GETARG_PGBSON(1);

	pgbsonsequence *deleteDocs = PG_GETARG_MAYBE_NULL_PGBSON_SEQUENCE(2);

	text *transactionId = NULL;
	if (!PG_ARGISNULL(3))
	{
		transactionId = PG_GETARG_TEXT_P(3);
	}

	ReportFeatureUsage(FEATURE_COMMAND_DELETE);

	/* fetch TupleDesc for return value, not interested in resultTypeId */
	Oid *resultTypeId = NULL;
	TupleDesc resultTupDesc;
	TypeFuncClass resultTypeClass =
		get_call_result_type(fcinfo, resultTypeId, &resultTupDesc);

	if (resultTypeClass != TYPEFUNC_COMPOSITE)
	{
		ereport(ERROR, (errmsg("return type must be a row type")));
	}

	ThrowIfServerOrTransactionReadOnly();

	bson_iter_t deleteCommandIter;
	PgbsonInitIterator(deleteSpec, &deleteCommandIter);

	/*
	 * We first validate delete command BSON and build a specification.
	 */
	BatchDeletionSpec *batchSpec = BuildBatchDeletionSpec(&deleteCommandIter, deleteDocs,
														  &databaseNameDatum);

	pgbson *batchResponse;

	Datum collectionNameDatum = CStringGetTextDatum(batchSpec->collectionName);
	MongoCollection *collection =
		GetMongoCollectionByNameDatum(databaseNameDatum, collectionNameDatum,
									  RowExclusiveLock);
	if (collection != NULL)
	{
		Oid shardOid = TryGetCollectionShardTable(collection, NoLock);
		if (shardOid == InvalidOid)
		{
			/* Shard not valid on this node anymore (due to shard moves etc) */
			collection->shardTableName[0] = '\0';
		}