A result set row represents a database result set unit, which is usually generated by executing a statement that queries the database. Using COM_STMT_EXECUTE, the result set row is in binary format, otherswise in text format.

Text Result Set Row

• For each column:

  • column data.

The byte representation of the string according to .

Binary Result Set Row

• byte<1> 0x00 header.

• byte<(number_of_columns + 7) / 8> .

• For each column:

  • If column value is not null:

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 . A DECIMAL(10,2) with a value of -15.5 is stored as:

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 .

INTEGER Binary Encoding

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

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 .

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 .

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.

• data length: 0 for special '00:00:00' value, 8 without fractional seconds, 12 with fractional seconds.

• If data length > 0:

  • 0 for positive time, 1 for negative time.

_{This page is licensed: CC BY-SA / Gnu FDL}

ERR_Packet indicates that an error occurred.

Fields

• int<1> ERR_Packet header = 0xFF.

• error code. see .

• If (error code == 0xFFFF) /* progress reporting */:

  • stage.

  • max_stage.

  • progress.
• Else:

  • If (next byte = '#'):

    • sql state marker '#'.

    • sql state.

See also

_{This page is licensed: CC BY-SA / Gnu FDL}

The EOF_Packet marks the end of a result set, and returns status and warnings.

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

Fields

• 0xfe : EOF header.

• warning count.

• .

_{This page is licensed: CC BY-SA / Gnu FDL}

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

Fields

• 0xFB : LOCAL_INFILE header.

• 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 or an .

_{This page is licensed: CC BY-SA / Gnu FDL}

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

• 0x00 : OK_Packet header or (0xFE if CLIENT_DEPRECATE_EOF is set).

• affected rows.

• last insert id.

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 . For the following OK_Packets it contains (if present) various human-readable information.

Server status flag

Values of server status flags:

Session state info

• While packet has remaining data:

  • .

  • If (session-change-type != SESSION_TRACK_STATE_CHANGE):

Session change type

Session Data Change

Each type of data has its own kind of format:

SESSION_TRACK_SCHEMA

• new current schema.

SESSION_TRACK_SYSTEM_VARIABLES

While there is remaining data:

• variable data.

For each variable data:

• variable name.

• variable value.

SESSION_TRACK_STATE_CHANGE

Indicates if session state changes occurred. The value is represented as 1.

• 1 if session state tracking was enabled.

SESSION_TRACK_GTIDS

This tracker is not implemented by MariaDB.

SESSION_TRACK_TRANSACTION_CHARACTERISTICS

• Transaction characteristics.

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

SESSION_TRACK_TRANSACTION_STATE

• 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: _

Notes

• To determine if session tracking is enabled, check if the flag is set in server_capabilities.

_{This page is licensed: CC BY-SA / Gnu FDL}

MariaDB Server sends the following packets as part of a result set.

A result set consists of different packets:

• Result set metadata.

  • 1 column count packet.

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

  • For each column (for instance, column_count times):

    • .

• If not (CLIENT_DEPRECATE_EOF capability set) .

• n .

• If error:

  • .

• Else:

  • If CLIENT_DEPRECATE_EOF capability:

    • with a 0xFE header.

Column Count Packet

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

• 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 follows the column definitions. If the metadata byte is set to 0, the Column Count Packet is immediately followed by the second or the result set 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:

• catalog (always 'def').

• schema.

• table alias.

• table.

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 result set 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 a column, the column type field is MYSQL_TYPE_GEOMETRY, but the extended type indicates 'point'.

• For a column, the column type field is MYSQL_TYPE_STRING, but the extended type indicates 'json'.

• While string has data:

_{This page is licensed: CC BY-SA / Gnu FDL}