Function DeleteAllMatchingDocuments

pg_documentdb/src/commands/delete.c:815–986

* DeleteAllMatchingDocuments deletes all documents that match the query. */

 * DeleteAllMatchingDocuments deletes all documents that match the query.
 */
static uint64
DeleteAllMatchingDocuments(MongoCollection *collection, pgbson *queryDoc,
						   const bson_value_t *variableSpec,
						   const char *collationString, bool hasShardKeyValueFilter,
						   int64 shardKeyHash)
{
	uint64 collectionId = collection->collectionId;

	bool applyCollation = IsCollationApplicable(collationString);

	bool queryHasNonIdFilters = false;
	bool isIdFilterCollationAware = false;
	pgbson *objectIdFilter = GetObjectIdFilterFromQueryDocument(queryDoc,
																&queryHasNonIdFilters,
																&isIdFilterCollationAware);
	bool applyObjectIdFilter = objectIdFilter != NULL;
	if (applyObjectIdFilter && applyCollation)
	{
		/* if the _id filter value is collation-sensitive, we will omit */
		/* filtering by _id in the WHERE clause. */
		applyObjectIdFilter = !isIdFilterCollationAware;
	}

	int argCount = 0;
	int nextSqlArgIndex = 1;
	uint64 rowsDeleted = 0;
	StringInfoData deleteQuery;

	SPI_connect();

	initStringInfo(&deleteQuery);
	appendStringInfo(&deleteQuery, "DELETE FROM ");

	if (collection->shardTableName[0] != '\0')
	{
		appendStringInfo(&deleteQuery, " %s.%s", ApiDataSchemaName,
						 collection->shardTableName);
	}
	else
	{
		appendStringInfo(&deleteQuery, " %s.documents_" UINT64_FORMAT, ApiDataSchemaName,
						 collectionId);
	}

	pgbson *variableSpecBson = NULL;
	if (queryHasNonIdFilters)
	{
		variableSpecBson = variableSpec != NULL &&
						   variableSpec->value_type == BSON_TYPE_DOCUMENT ?
						   PgbsonInitFromDocumentBsonValue(variableSpec) : NULL;
	}

	bool applyVariableSpec = variableSpecBson != NULL;
	if (applyVariableSpec || applyCollation)
	{
		/* utilize the collation and/or variables in matching the document */
		appendStringInfo(&deleteQuery,
						 " WHERE %s.bson_query_match(document, $1::%s.bson, $2::%s.bson, $3::text)",