Function UpdateOneInternal

pg_documentdb/src/commands/update.c:3201–3378

* UpdateOneInternal updates a single document with a specific shard key value filter. * Returns whether a document was updated and if so sets the updatedDocument and * whether reinsertion will be required (due to shard key value change). */

 * whether reinsertion will be required (due to shard key value change).
 */
static void
UpdateOneInternal(MongoCollection *collection, UpdateOneParams *updateOneParams,
				  int64 shardKeyHash, UpdateOneResult *result,
				  ExprEvalState *stateForSchemaValidation)
{
	/* initialize result */
	memset(result, 0, sizeof(UpdateOneResult));

	UpdateCandidate updateCandidate = { 0 };

	bool getExistingDoc = updateOneParams->returnDocument != UPDATE_RETURNS_NONE ||
						  updateOneParams->returnFields != NULL ||
						  NeedExistingDocForValidation(stateForSchemaValidation,
													   collection);
	bool hasOnlyObjectIdFilter = false;
	bool foundDocument = SelectUpdateCandidate(collection,
											   shardKeyHash,
											   updateOneParams,
											   &updateCandidate,
											   getExistingDoc,
											   &hasOnlyObjectIdFilter);

	if (!foundDocument)
	{
		/* no documents matched the query */

		if (updateOneParams->isUpsert)
		{
			pgbson *emptyDocument = PgbsonInitEmpty();

			/*
			 * Perform regular bson update document because this is an upsert case without
			 * update change tracking
			 */
			pgbson *newDoc = BsonUpdateDocument(emptyDocument, updateOneParams->update,
												updateOneParams->query,
												updateOneParams->arrayFilters,
												updateOneParams->variableSpec);

			pgbson *objectId = PgbsonGetDocumentId(newDoc);

			int64 newShardKeyHash =
				ComputeShardKeyHashForDocument(collection->shardKey,
											   collection->collectionId, newDoc);

			if (EnableSchemaValidation && stateForSchemaValidation != NULL)
			{
				bson_value_t newDocValue = ConvertPgbsonToBsonValue(newDoc);
				ValidateSchemaOnDocumentInsert(stateForSchemaValidation, &newDocValue,
											   FAILED_VALIDATION_ERROR_MSG);
			}

			if (newShardKeyHash == shardKeyHash)
			{
				/* shard key unchanged, upsert now */
				DoInsertForUpdate(collection, newShardKeyHash, objectId, newDoc,
								  hasOnlyObjectIdFilter, updateOneParams->update);
				result->reinsertDocument = NULL;