This is a command-line option for the
Creates a consistent snapshot by dumping all tables in a single transaction. Works ONLY for tables stored in storage engines which support multiversioning (currently only InnoDB does); the dump is NOT guaranteed to be consistent for other storage engines. While a --single-transaction dump is in process, to ensure a valid dump file (correct table contents and binary log position), no other connection should use the following statements: ALTER TABLE, DROP TABLE, RENAME TABLE, TRUNCATE TABLE, as consistent snapshot is not isolated from them. Option automatically turns off --lock-tables.
Information specific to MariaDB SkySQL can be found on the single-transaction page in the SkySQL Documentation.