protocol.cc File Reference

#include "sql_priv.h"
#include "unireg.h"
#include "protocol.h"
#include "sql_class.h"
#include <stdarg.h>

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Functions
bool	net_send_error_packet (THD *, uint, const char *, const char *)
bool	net_send_ok (THD *, uint, uint, ulonglong, ulonglong, const char *)
bool	net_send_eof (THD *thd, uint server_status, uint statement_warn_count)
bool	net_send_error (THD *thd, uint sql_errno, const char *err, const char *sqlstate)
uchar *	net_store_data (uchar *to, const uchar *from, size_t length)
uchar *	net_store_data (uchar *to, int32 from)
uchar *	net_store_data (uchar *to, longlong from)

Detailed Description

Low level functions for storing data to be send to the MySQL client. The actual communction is handled by the net_xxx functions in net_serv.cc

Definition in file protocol.cc.

Function Documentation

bool net_send_eof	(	THD *	thd,
		uint	server_status,
		uint	statement_warn_count
	)

Send eof (= end of result set) to the client.

The eof packet has the following structure:

• 254 : Marker (1 byte)
• warning_count : Stored in 2 bytes; New in 4.1 protocol
• status_flag : Stored in 2 bytes; For flags like SERVER_MORE_RESULTS_EXISTS.

Note that the warning count will not be sent if 'no_flush' is set as we don't want to report the warning count until all data is sent to the client.

Parameters

thd	Thread handler
server_status	The server status
statement_warn_count	Total number of warnings

Returns

Return values

FALSE	The message was successfully sent
TRUE	An error occurred and the message wasn't sent properly

Definition at line 286 of file protocol.cc.

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bool net_send_error	(	THD *	thd,
		uint	sql_errno,
		const char *	err,
		const char *	sqlstate
	)

Send a error string to client.

Design note:

net_printf_error and net_send_error are low-level functions that shall be used only when a new connection is being established or at server startup.

For SIGNAL/RESIGNAL and GET DIAGNOSTICS functionality it's critical that every error that can be intercepted is issued in one place only, my_message_sql.

Parameters

thd	Thread handler
sql_errno	The error code to send
err	A pointer to the error message

Returns

Return values

FALSE	The message was sent to the client
TRUE	An error occurred and the message wasn't sent properly

Definition at line 145 of file protocol.cc.

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bool net_send_error_packet	(	THD *	thd,
		uint	sql_errno,
		const char *	err,
		const char *	sqlstate
	)

Parameters

thd	Thread handler
sql_errno	The error code to send
err	A pointer to the error message

Returns

Return values

FALSE	The message was successfully sent
TRUE	An error occurred and the messages wasn't sent properly

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bool net_send_ok	(	THD *	thd,
		uint	server_status,
		uint	statement_warn_count,
		ulonglong	affected_rows,
		ulonglong	id,
		const char *	message
	)

Return ok to the client.

The ok packet has the following structure:

• 0 : Marker (1 byte)
• affected_rows : Stored in 1-9 bytes
• id : Stored in 1-9 bytes
• server_status : Copy of thd->server_status; Can be used by client to check if we are inside an transaction. New in 4.0 protocol
• warning_count : Stored in 2 bytes; New in 4.1 protocol
• message : Stored as packed length (1-9 bytes) + message. Is not stored if no message.

Parameters

thd	Thread handler
server_status	The server status
statement_warn_count	Total number of warnings
affected_rows	Number of rows changed by statement
id	Auto_increment id for first row (if used)
message	Message to send to the client (Used by mysql_status)

Returns

Return values

FALSE	The message was successfully sent
TRUE	An error occurred and the messages wasn't sent properly

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