OkPacket

Object

The OkPacket is a response object from MySQL that provides metadata about a successfully executed query. It contains details such as the number of affected rows, insert IDs, server status, warnings, and protocol information. This packet is typically returned for INSERT, UPDATE, DELETE, and other non-SELECT statements.

Structure

Property	Type	Description
fieldCount	Number	Defaults to 0 for non-SELECT queries.
affectedRows	Number	The number of rows affected by the query (does not necessarily mean all rows were changed).
insertId	Number	The ID of the last inserted row (if an auto-increment column exists, otherwise 0).
serverStatus	Number	A bitmask flag representing the current state of the MySQL server.
warningCount	Number	The number of warnings generated during query execution.
message	String	An optional message providing additional information about the query result (typically empty).
protocol41	Boolean	true if MySQL protocol 4.1 or later is used.
changedRows	Number	The number of rows actually modified by the query.

Common serverStatus Flags

Bitmask Behavior

serverStatus is a bitmask, meaning multiple statuses can be active at the same time.

For example:

• SERVER_STATUS_AUTOCOMMIT (1) + SERVER_STATUS_IN_TRANS (2)
• These combine to 3 (1 | 2 = 3) through a bitwise OR operation.

serverStatus-Value	Status	Description
1	SERVER_STATUS_AUTOCOMMIT	The server is in autocommit mode, treating each query as a seperate transaction that commits automatically.
2	SERVER_STATUS_IN_TRANS	The server is currently in a transaction (queries have not been committed yet).
8	SERVER_STATUS_MORE_RESULTS_EXISTS	More result sets exist (e.g., when executing a SELECT ... INTO OUTFILE query).
16	SERVER_STATUS_NO_GOOD_INDEX_USED	The server did not use an optimal index for the query, which may indicate inefficient execution.
32	SERVER_STATUS_NO_INDEX_USED	The query was executed without an index, likely causing a full table scan (may impact performance).
64	SERVER_STATUS_QUERY_NO_GOOD_INDEX_USED	No suitable index was used during query execution (could result in performance issues).
128	SERVER_STATUS_CURSOR_EXISTS	A cursor exists and is in use for this query (typically seen in more complex queries).
256	SERVER_STATUS_LAST_INSERT_ID	The last executed INSERT statement generated an AUTO_INCREMENT ID.
512	SERVER_STATUS_DB_DROPPED	A database was dropped as part of the executed query.