Function PerformUpdateCore

pg_documentdb/src/commands/update.c:565–696

static HeapTuple
PerformUpdateCore(Datum *databaseNameDatum, pgbson *updateSpec,
				  pgbsonsequence *updateDocs, text *transactionId,
				  TupleDesc resultTupDesc, WriteMode writeMode,
				  MemoryContext allocContext)
{
	ThrowIfServerOrTransactionReadOnly();
	bson_iter_t updateCommandIter;
	PgbsonInitIterator(updateSpec, &updateCommandIter);

	BatchUpdateResult batchResult;
	memset(&batchResult, 0, sizeof(batchResult));
	batchResult.resultMemoryContext = allocContext;

	/*
	 * We first validate update command BSON and build a specification.
	 */
	MemoryContext oldContext = MemoryContextSwitchTo(allocContext);
	BatchUpdateSpec *batchSpec = BuildBatchUpdateSpec(&updateCommandIter, updateDocs,
													  databaseNameDatum);

	Datum collectionNameDatum = CStringGetTextDatum(batchSpec->collectionName);
	MongoCollection *collection =
		GetMongoCollectionByNameDatum(*databaseNameDatum, collectionNameDatum,
									  RowExclusiveLock);
	MemoryContextSwitchTo(oldContext);

	Datum values[2];
	bool isNulls[2] = { false, false };
	HeapTuple resultTuple;
	if (collection == NULL)
	{
		/* We have to create the update spec here to ensure we track hasUpsert */
		oldContext = MemoryContextSwitchTo(allocContext);
		BuildUpdates(batchSpec);
		MemoryContextSwitchTo(oldContext);

		ValidateCollectionNameForUnauthorizedSystemNs(batchSpec->collectionName,
													  *databaseNameDatum);

		if (batchSpec->hasUpsert)
		{
			/* upsert on a non-existent collection creates the collection */
			collection = CreateCollectionForInsert(*databaseNameDatum,
												   collectionNameDatum);
		}
		else
		{
			/*
			 * Pure update without upsert on non-existent collection is a noop,
			 * but we still need to report (write) errors due to invalid query
			 * / update documents.
			 */
			batchResult.ok = 1;
			batchResult.rowsMatched = 0;
			batchResult.rowsModified = 0;
			batchResult.writeErrors = ValidateQueryAndUpdateDocuments(batchSpec);
			batchResult.upserted = NIL;