The eof packet marks the end of a resultset and returns status and warnings.

When testing for an EOF packet, the packet size must be less than 9 bytes in length. Resultset can send data that begins with a 0xfe byte, but then the packet length will be greater than 9.

Fields

• int<1> 0xfe : EOF header

• int<2> warning count

• int<2> server status

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ERR_Packet

ERR_Packet indicates that an error occured.

Fields

• int<1> ERR_Packet header = 0xFF

• int<2> error code. see error list

• if (errorcode == 0xFFFF) /* progress reporting */

  • int<1> stage

  • int<1> max_stage

  • int<3> progress

  • string progress_info

• else

  • if (next byte = '#')

    • string<1> sql state marker '#'

    • string<5>sql state

    • string human-readable error message

  • else

    • string human-readable error message

Note that the ERR packet is supposed to send a server error to the client. In particular, all error codes in the range 2000 to 2999 and 5000 to 5999 (inclusive) are reserved for client errors and an ERR packet with such an error code will be considered malformed.

See also

"Progress reporting"

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OK_Packet is sent by the server to the client and indicates a successful completion of a command sent by the client before.

Direction

Server to client.

Fields

• int<1> 0x00 : OK_Packet header or (0xFE if CLIENT_DEPRECATE_EOF is set)

• int affected rows

• int last insert id

• int<2> server status

• int<2> warning count

• if packet has more data

  • string info

  • if (status flags & SERVER_SESSION_STATE_CHANGED) and session_tracking_supported (see CLIENT_SESSION_TRACK)

    • string session state info

The length-encoded info string is not always included in the packet. Check the length of the packet to detect if there is data after the warning count. For the first OK_Packet in the connection it contains (if present) the SSL certificate verification signature. For the following OK_Packets it contains (if present) various human-readable information.

Server status flag

Values of server status flag

Session state info

• while packet has remaining data

  • int<1> session change type

  • if (session-change-type != SESSION_TRACK_STATE_CHANGE)

    • int total length

  • string session data's change

Session change type

session data's change

Each type of data has his own kind of format :

SESSION_TRACK_SCHEMA

• string new current schema

SESSION_TRACK_SYSTEM_VARIABLES

while there is remaining data :

• string variable data

for each variable data :

• string variable name

• string variable value

SESSION_TRACK_STATE_CHANGE

indicates if session state changes occured. The value is represented as "1".

• string "1" if session state tracking was enabled

SESSION_TRACK_GTIDS

This tracker is not implemented by MariaDB.

SESSION_TRACK_TRANSACTION_CHARACTERISTICS

• string Transaction characteristics

The transaction characteristics is the set of SQL statements that reproduces the type and state of the current transaction. It can consist of the following SQL statements:

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
START TRANSACTION;
START TRANSACTION WITH CONSISTENT SNAPSHOT;
START TRANSACTION WITH CONSISTENT SNAPSHOT, READ ONLY;
START TRANSACTION WITH CONSISTENT SNAPSHOT, READ WRITE;
SET TRANSACTION READ ONLY;
SET TRANSACTION READ WRITE;
XA START <XA specification>;

SESSION_TRACK_TRANSACTION_STATE

• string Transaction state string

The transaction state string is always 8 characters long. The characters, in order, are:

1. No transaction: _ Explicit transaction: T Implicit transaction: I

2. Transaction read safe: _ Transaction read unsafe: r

3. Unknown transaction type: _ Read-only transaction: R

4. Transaction write safe: _ Transaction write unsafe: w

5. Unknown transaction type: _ Read-write transaction: W

6. Transaction statement safe: _ Transaction statement unsafe: s

7. Transaction does not have resultsets: _ Transaction with resultsets: S

8. No locked tables: _ Tables have been locked: L

Notes

• Session tracking is supported from MariaDB 10.2. To determine if session tracking is enabled, check if the CLIENT_SESSION_TRACK flag is set in server_capabilities.

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LOCAL_INFILE Packet

If the client sends a LOAD DATA LOCAL INFILE command via com_query, the server responds with LOCAL_INFILE_Packet to tell the client to send a specified file to the server.

Fields

• int<1> 0xFB : LOCAL_INFILE header

• string filename

Client response

The client sends the file as the packet body. If the file is large, the contents are sent in multiple separate packets. After the file is sent, the client must send an empty packet to indicate that no more data will follow.

Once the client has finished sending the file, the server will respond with an OK_packet or an ERR_packet.

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MariaDB Server sends the following packets as part of a result set: A resultset consists of different packets:

• Resultset metadata

  • 1 Column count packet

• if not (MARIADB_CLIENT_CACHE_METADATA capability set) OR (send metadata == 1)

  • for each column (i.e column_count times)

    • Column Definition packet

• if not (CLIENT_DEPRECATE_EOF capability set) EOF_Packet

• n resultset row

• if error

  • ERR_Packet

• else

  • if CLIENT_DEPRECATE_EOF capability

    • OK_Packet with a 0xFE header

  • else EOF_Packet

Column Count Packet

The column count packet describes the number of columns in the result set. It uses the following format:

• int column count

• if (MARIADB_CLIENT_CACHE_METADATA capability set)

  • int<1> metadata follows (0 / 1)

The metadata indicator byte is only present if both the client and the server declare the MARIADB_CLIENT_CACHE_METADATA capability.

If the metadata byte is set to 1, the normal metadata will follow the column definitions. If the metadata byte is set to 0, the Column Count Packet is immediately followed by the second EOF packet (EOF_Packet) or the resultset rows if the CLIENT_DEPRECATE_EOF capability is set.

Column Definition Packet

A column definition packet describes a column in the result set. It uses the following format:

• string catalog (always 'def')

• string schema

• string table alias

• string table

• string column alias

• string column

• if extended type supported (see MARIADB_CLIENT_EXTENDED_METADATA )

  • string extended metadata

• int length of fixed fields (=0xC)

• int<2> character set number

• int<4> max. column size

• int<1> Field types

• int<2> Field detail flag

• int<1> decimals

• int<2> - unused -

Field types

The column type field in the column definition packet describes the base type of the column. It also indicates how the values are encoded for COM_STMT_EXECUTE parameters and binary resultset rows.

Field Details Flag

The column details flag describes certain column attributes and whether certain column options are set.

It is a bitmask with the following flags:

Extended metadata

This extended column type information can be used to find out more specific details about the column type.

For example:

• For a POINT column, the column type field will be MYSQL_TYPE_GEOMETRY, but the extended type will indicate 'point'.

• For a JSON column, the column type field will be MYSQL_TYPE_STRING, but the extended type will indicate 'json'.

• while string has data

  • int<1> data type: 0x00:type, 0x01: format

  • string value

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A resultset row represents a database resultset unit, which is usually generated by executing a statement that queries the database. Using COM_STMT_EXECUTE the resultsetrow will be in binary format, others in text format.

Text resultset row

• for each column

  • string column data

The byte representation of the string according to client character collation.

Binary resultset row

• byte<1> 0x00 header

• byte<(number_of_columns + 7) / 8> NULL-Bitmap

• for each column

  • if column value is not null

    • if MYSQL_TYPE_DOUBLE type : DOUBLE Binary encoding

    • if MYSQL_TYPE_LONGLONG type : BIGINT Binary encoding

    • if MYSQL_TYPE_INTEGER type : INTEGER Binary encoding

    • if MYSQL_TYPE_MEDIUMINT type : MEDIUMINT Binary encoding

    • if MYSQL_TYPE_FLOAT type : FLOAT Binary encoding

    • if MYSQL_TYPE_SMALLINT type : SMALLINTBinary encoding

    • if MYSQL_TYPE_YEAR type : YEAR Binary encoding

    • if MYSQL_TYPE_TINYINT type : TINYINT Binary encoding

    • if MYSQL_TYPE_DATE type : DATE Binary encoding

    • if MYSQL_TYPE_TIMESTAMP type : TIMESTAMP Binary encoding

    • if MYSQL_TYPE_DATETIME type : TIMESTAMP Binary encoding

    • if MYSQL_TYPE_TIME type : TIME Binary encoding

    • if MYSQL_TYPE_NEWDECIMAL type : DECIMAL Binary encoding

    • if MYSQL_TYPE_TINY_BLOB, MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, MYSQL_TYPE_BLOB, MYSQL_TYPE_GEOMETRY,MYSQL_TYPE_STRING, MYSQL_TYPE_VARCHAR, MYSQL_TYPE_VAR_STRING): byte value

NULL-Bitmap values

The NULL-Bitmap indicates if a parameter for a column is null (one bit per parameter) beginning with the 3rd bit. NULL-bitmap size is (number_of_columns + 7) / 8.

DECIMAL Binary encoding.

DECIMAL has no fixed size, so will be encoded as string. An DECIMAL(10,2) with a value of -15.5 is stored as

06 45 49 53 46 53 48      . - 1 5 . 5 0

DOUBLE binary encoding

DOUBLE is the IEEE 754 floating-point value in Little-endian format on 8 bytes.

BIGINT binary encoding

BIGINT is the value in Little-endian format on 8 bytes. Signed is defined by the Column field detail flag.

INTEGER binary encoding

INTEGER is the value in Little-endian format on 4 bytes. Signed is defined by the Column field detail flag.

MEDIUMINT binary encoding

MEDIUMINT is similar to INTEGER binary encoding, even if MEDIUM int is 3-bytes encoded server side. (Last byte will always be 0x00).

FLOAT binary encoding

FLOAT is the IEEE 754 floating-point value in Little-endian format on 4 bytes.

SMALLINT binary encoding

SMALLINT is the value in Little-endian format on 2 bytes. Signed is defined by the Column field detail flag.

YEAR binary encoding

YEAR uses the same format as SMALLINT.

TINYINT binary encoding

TINYINT is the value of 1 byte. Signed is defined by the Column field detail flag.

DATE binary encoding

DATE uses the same format as TIMESTAMP binary encoding, with a data length of 0 for the special '0000-00-00' value and 4 for the standard year/month/day format

TIMESTAMP binary encoding

Data is encoded in 8 bytes without fractional seconds, 12 bytes with fractional seconds.

TIME binary encoding

Data is encoded in 9 bytes without fractional seconds, 13 bytes with fractional seconds.

• int<1> data length: 0 for special '00:00:00' value, 8 without fractional seconds, 12 with fractional seconds

• if data length > 0

  • int<1> 0 for positive time, 1 for negative time

  • int<4> days

  • int<1> hours

  • int<1> minutes

  • int<1> seconds

  • if data length > 8

    • int<4> microseconds

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