MySQL  8.0.16
Source Code Documentation
Capabilities Flags

Values for the capabilities flag bitmask used by the MySQL protocol. More...

Macros

#define CLIENT_LONG_PASSWORD   1
 Use the improved version of Old Password Authentication. More...
 
#define CLIENT_FOUND_ROWS   2
 Send found rows instead of affected rows in EOF_Packet. More...
 
#define CLIENT_LONG_FLAG   4
 Get all column flags. More...
 
#define CLIENT_CONNECT_WITH_DB   8
 Database (schema) name can be specified on connect in Handshake Response Packet. More...
 
#define CLIENT_NO_SCHEMA   16
 Don't allow database.table.column. More...
 
#define CLIENT_COMPRESS   32
 Compression protocol supported. More...
 
#define CLIENT_ODBC   64
 Special handling of ODBC behavior. More...
 
#define CLIENT_LOCAL_FILES   128
 Can use LOAD DATA LOCAL. More...
 
#define CLIENT_IGNORE_SPACE   256
 Ignore spaces before '('. More...
 
#define CLIENT_PROTOCOL_41   512
 New 4.1 protocol. More...
 
#define CLIENT_INTERACTIVE   1024
 This is an interactive client. More...
 
#define CLIENT_SSL   2048
 Use SSL encryption for the session. More...
 
#define CLIENT_IGNORE_SIGPIPE   4096
 Client only flag. More...
 
#define CLIENT_TRANSACTIONS   8192
 Client knows about transactions. More...
 
#define CLIENT_RESERVED   16384
 DEPRECATED: Old flag for 4.1 protocol. More...
 
#define CLIENT_RESERVED2   32768
 DEPRECATED: Old flag for 4.1 authentication \ CLIENT_SECURE_CONNECTION. More...
 
#define CLIENT_MULTI_STATEMENTS   (1UL << 16)
 Enable/disable multi-stmt support. More...
 
#define CLIENT_MULTI_RESULTS   (1UL << 17)
 Enable/disable multi-results. More...
 
#define CLIENT_PS_MULTI_RESULTS   (1UL << 18)
 Multi-results and OUT parameters in PS-protocol. More...
 
#define CLIENT_PLUGIN_AUTH   (1UL << 19)
 Client supports plugin authentication. More...
 
#define CLIENT_CONNECT_ATTRS   (1UL << 20)
 Client supports connection attributes. More...
 
#define CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA   (1UL << 21)
 Enable authentication response packet to be larger than 255 bytes. More...
 
#define CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS   (1UL << 22)
 Don't close the connection for a user account with expired password. More...
 
#define CLIENT_SESSION_TRACK   (1UL << 23)
 Capable of handling server state change information. More...
 
#define CLIENT_DEPRECATE_EOF   (1UL << 24)
 Client no longer needs EOF_Packet and will use OK_Packet instead. More...
 
#define CLIENT_SSL_VERIFY_SERVER_CERT   (1UL << 30)
 Verify server certificate. More...
 
#define CLIENT_OPTIONAL_RESULTSET_METADATA   (1UL << 25)
 The client can handle optional metadata information in the resultset. More...
 
#define CLIENT_REMEMBER_OPTIONS   (1UL << 31)
 Don't reset the options after an unsuccessful connect. More...
 

Detailed Description

Values for the capabilities flag bitmask used by the MySQL protocol.

Currently need to fit into 32 bits.

Each bit represents an optional feature of the protocol.

Both the client and the server are sending these.

The intersection of the two determines whast optional parts of the protocol will be used.

Macro Definition Documentation

◆ CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS

#define CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS   (1UL << 22)

Don't close the connection for a user account with expired password.

Server

Announces support for expired password extension.

Client

Can handle expired passwords.

See also
MYSQL_OPT_CAN_HANDLE_EXPIRED_PASSWORDS, disconnect_on_expired_password ACL_USER::password_expired, check_password_lifetime(), acl_authenticate()

◆ CLIENT_COMPRESS

#define CLIENT_COMPRESS   32

Compression protocol supported.

Server

Supports compression.

Client

Switches to Compression compressed protocol after successful authentication.

◆ CLIENT_CONNECT_ATTRS

#define CLIENT_CONNECT_ATTRS   (1UL << 20)

Client supports connection attributes.

Server

Permits connection attributes in Protocol::HandshakeResponse41.

Client

Sends connection attributes in Protocol::HandshakeResponse41.

See also
send_client_connect_attrs(), read_client_connect_attrs()

◆ CLIENT_CONNECT_WITH_DB

#define CLIENT_CONNECT_WITH_DB   8

Database (schema) name can be specified on connect in Handshake Response Packet.

Server

Supports schema-name in Handshake Response Packet.

Client

Handshake Response Packet contains a schema-name.

See also
send_client_reply_packet()

◆ CLIENT_DEPRECATE_EOF

#define CLIENT_DEPRECATE_EOF   (1UL << 24)

Client no longer needs EOF_Packet and will use OK_Packet instead.

See also
net_send_ok()

Server

Can send OK after a Text Resultset.

Client

Expects an OK_Packet (instead of EOF_Packet) after the resultset rows of a Text Resultset.

Background

To support CLIENT_SESSION_TRACK, additional information must be sent after all successful commands. Although the OK_Packet is extensible, the EOF_Packet is not due to the overlap of its bytes with the content of the Text Resultset Row.

Therefore, the EOF_Packet in the Text Resultset is replaced with an OK_Packet. EOF_Packet is deprecated as of MySQL 5.7.5.

See also
cli_safe_read_with_ok(), read_ok_ex(), net_send_ok(), net_send_eof()

◆ CLIENT_FOUND_ROWS

#define CLIENT_FOUND_ROWS   2

Send found rows instead of affected rows in EOF_Packet.

◆ CLIENT_IGNORE_SIGPIPE

#define CLIENT_IGNORE_SIGPIPE   4096

Client only flag.

Not used.

Client

Do not issue SIGPIPE if network failures occur (libmysqlclient only).

See also
mysql_real_connect()

◆ CLIENT_IGNORE_SPACE

#define CLIENT_IGNORE_SPACE   256

Ignore spaces before '('.

Server

Parser can ignore spaces before '('.

Client

Let the parser ignore spaces before '('.

◆ CLIENT_INTERACTIVE

#define CLIENT_INTERACTIVE   1024

This is an interactive client.

Use System_variables::net_wait_timeout versus System_variables::net_interactive_timeout.

Server

Supports interactive and noninteractive clients.

Client

Client is interactive.

See also
mysql_real_connect()

◆ CLIENT_LOCAL_FILES

#define CLIENT_LOCAL_FILES   128

Can use LOAD DATA LOCAL.

Server

Enables the LOCAL INFILE request of LOAD DATA|XML.

Client

Will handle LOCAL INFILE request.

◆ CLIENT_LONG_FLAG

#define CLIENT_LONG_FLAG   4

Get all column flags.

Longer flags in Protocol::ColumnDefinition320.

Server

Supports longer flags.

Client

Expects longer flags.

◆ CLIENT_LONG_PASSWORD

#define CLIENT_LONG_PASSWORD   1

Use the improved version of Old Password Authentication.

Not used.

Note
Assumed to be set since 4.1.1.

◆ CLIENT_MULTI_RESULTS

#define CLIENT_MULTI_RESULTS   (1UL << 17)

Enable/disable multi-results.

Server

Can send multiple resultsets for COM_QUERY. Error if the server needs to send them and client does not support them.

Client

Can handle multiple resultsets for COM_QUERY.

Requires

CLIENT_PROTOCOL_41

See also
mysql_execute_command(), sp_head::MULTI_RESULTS

◆ CLIENT_MULTI_STATEMENTS

#define CLIENT_MULTI_STATEMENTS   (1UL << 16)

Enable/disable multi-stmt support.

Also sets CLIENT_MULTI_RESULTS. Currently not checked anywhere.

Server

Can handle multiple statements per COM_QUERY and COM_STMT_PREPARE.

Client

May send multiple statements per COM_QUERY and COM_STMT_PREPARE.

Note
Was named CLIENT_MULTI_QUERIES in 4.1.0, renamed later.

Requires

CLIENT_PROTOCOL_41

◆ CLIENT_NO_SCHEMA

#define CLIENT_NO_SCHEMA   16

Don't allow database.table.column.

◆ CLIENT_ODBC

#define CLIENT_ODBC   64

Special handling of ODBC behavior.

Note
No special behavior since 3.22.

◆ CLIENT_OPTIONAL_RESULTSET_METADATA

#define CLIENT_OPTIONAL_RESULTSET_METADATA   (1UL << 25)

The client can handle optional metadata information in the resultset.

◆ CLIENT_PLUGIN_AUTH

#define CLIENT_PLUGIN_AUTH   (1UL << 19)

Client supports plugin authentication.

Server

Sends extra data in Initial Handshake Packet and supports the pluggable authentication protocol.

Client

Supports authentication plugins.

Requires

CLIENT_PROTOCOL_41

See also
send_change_user_packet(), send_client_reply_packet(), run_plugin_auth(), parse_com_change_user_packet(), parse_client_handshake_packet()

◆ CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA

#define CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA   (1UL << 21)

Enable authentication response packet to be larger than 255 bytes.

When the ability to change default plugin require that the initial password field in the Protocol::HandshakeResponse41 paclet can be of arbitrary size. However, the 4.1 client-server protocol limits the length of the auth-data-field sent from client to server to 255 bytes. The solution is to change the type of the field to a true length encoded string and indicate the protocol change with this client capability flag.

Server

Understands length-encoded integer for auth response data in Protocol::HandshakeResponse41.

Client

Length of auth response data in Protocol::HandshakeResponse41 is a length-encoded integer.

Note
The flag was introduced in 5.6.6, but had the wrong value.
See also
send_client_reply_packet(), parse_client_handshake_packet(), get_56_lenc_string(), get_41_lenc_string()

◆ CLIENT_PROTOCOL_41

#define CLIENT_PROTOCOL_41   512

New 4.1 protocol.

Server

Supports the 4.1 protocol.

Client

Uses the 4.1 protocol.

Note
this value was CLIENT_CHANGE_USER in 3.22, unused in 4.0

◆ CLIENT_PS_MULTI_RESULTS

#define CLIENT_PS_MULTI_RESULTS   (1UL << 18)

Multi-results and OUT parameters in PS-protocol.

Server

Can send multiple resultsets for COM_STMT_EXECUTE.

Client

Can handle multiple resultsets for COM_STMT_EXECUTE.

Requires

CLIENT_PROTOCOL_41

See also
Protocol_binary::send_out_parameters

◆ CLIENT_REMEMBER_OPTIONS

#define CLIENT_REMEMBER_OPTIONS   (1UL << 31)

Don't reset the options after an unsuccessful connect.

Client only flag.

Typically passed via mysql_real_connect() 's client_flag parameter.

See also
mysql_real_connect()

◆ CLIENT_RESERVED

#define CLIENT_RESERVED   16384

DEPRECATED: Old flag for 4.1 protocol.

◆ CLIENT_RESERVED2

#define CLIENT_RESERVED2   32768

DEPRECATED: Old flag for 4.1 authentication \ CLIENT_SECURE_CONNECTION.

◆ CLIENT_SESSION_TRACK

#define CLIENT_SESSION_TRACK   (1UL << 23)

Capable of handling server state change information.

Its a hint to the server to include the state change information in OK_Packet.

Server

Can set SERVER_SESSION_STATE_CHANGED in the SERVER_STATUS_flags_enum and send Session State Information in a OK_Packet.

Client

Expects the server to send Session State Information in a OK_Packet.

See also
enum_session_state_type, read_ok_ex(), net_send_ok(), Session_tracker, State_tracker

◆ CLIENT_SSL

#define CLIENT_SSL   2048

Use SSL encryption for the session.

Server

Supports SSL

Client

Switch to SSL after sending the capability-flags.

◆ CLIENT_SSL_VERIFY_SERVER_CERT

#define CLIENT_SSL_VERIFY_SERVER_CERT   (1UL << 30)

Verify server certificate.

Client only flag.

Deprecated:
in favor of –ssl-mode.

◆ CLIENT_TRANSACTIONS

#define CLIENT_TRANSACTIONS   8192

Client knows about transactions.

Server

Can send status flags in OK_Packet / EOF_Packet.

Client

Expects status flags in OK_Packet / EOF_Packet.

Note
This flag is optional in 3.23, but always set by the server since 4.0.
See also
send_server_handshake_packet(), parse_client_handshake_packet(), net_send_ok(), net_send_eof()