Used for rate-limiting the slow query log. More...

#include <log.h>

Inheritance diagram for Slow_log_throttle:

Public Member Functions
	Slow_log_throttle (ulong threshold, mysql_mutex_t lock, ulong window_usecs, log_summary_t logger, const char *msg)

bool	flush (THD *thd)
	Prepare and print a summary of suppressed lines to log. More...

bool	log (THD *thd, bool eligible)
	Top-level function. More...

Private Member Functions
void	new_window (ulonglong now)
	Start a new window. More...

void	print_summary (THD *thd, ulong suppressed, ulonglong print_lock_time, ulonglong print_exec_time)
	Actually print the prepared summary to log. More...

Private Attributes
Security_context	aggregate_sctx
	We're using our own (empty) security context during summary generation. More...

ulonglong	total_exec_time
	Total of the execution times of queries in this time-window for which we suppressed logging. More...

ulonglong	total_lock_time
	Total of the lock times of queries in this time-window for which we suppressed logging. More...

ulong *	rate
	A reference to the threshold ("no more than n log lines per ..."). More...

log_summary_t	log_summary
	The routine we call to actually log a line (our summary). More...

mysql_mutex_t *	LOCK_log_throttle
	Slow_log_throttle is shared between THDs. More...

Additional Inherited Members
Static Public Attributes inherited from Log_throttle
static const ulong	LOG_THROTTLE_WINDOW_SIZE = 60000000
	We're rate-limiting messages per minute; 60,000,000 microsecs = 60s Debugging is less tedious with a window in the region of 5000000. More...

Protected Member Functions inherited from Log_throttle
void	new_window (ulonglong now)
	Start a new window. More...

bool	inc_log_count (ulong rate)
	Increase count of logs we're handling. More...

bool	in_window (ulonglong now) const
	Check whether we're still in the current window. More...

ulong	prepare_summary (ulong rate)
	Prepare a summary of suppressed lines for logging. More...

	Log_throttle (ulong window_usecs, const char *msg)

Protected Attributes inherited from Log_throttle
const char *	summary_template
	Template for the summary line. More...

Detailed Description

Used for rate-limiting the slow query log.

Used for rate-limiting a error logs.

Constructor & Destructor Documentation

◆ Slow_log_throttle()

Slow_log_throttle::Slow_log_throttle	(	ulong *	threshold,
		mysql_mutex_t *	lock,
		ulong	window_usecs,
		log_summary_t	logger,
		const char *	msg
	)

Parameters

threshold	suppress after this many queries ...
lock	mutex to use for consistency of calculations
window_usecs	... in this many micro-seconds
logger	call this function to log a single line (our summary)
msg	use this template containing lu as only non-literal

Member Function Documentation

◆ flush()

bool Slow_log_throttle::flush ( THD * thd )

Prepare and print a summary of suppressed lines to log.

(For now, slow query log.) The summary states the number of queries that were qualified for inclusion in the log, but were not printed because of the rate-limiting, and their respective totals for lock and execution time. This wrapper for prepare_summary() and print_summary() handles the locking/unlocking.

Parameters

thd	The THD that tries to log the statement.

Return values

false	Logging was not suppressed, no summary needed.
true	Logging was suppressed; a summary was printed.

◆ log()

bool Slow_log_throttle::log	(	THD *	thd,
		bool	eligible
	)

Top-level function.

Parameters

thd	The THD that tries to log the statement.
eligible	Is the statement of the type we might suppress?

Return values

true	Logging should be suppressed.
false	Logging should not be suppressed.

◆ new_window()

void Slow_log_throttle::new_window ( ulonglong now )

private

Start a new window.

◆ print_summary()

void Slow_log_throttle::print_summary	(	THD *	thd,
		ulong	suppressed,
		ulonglong	print_lock_time,
		ulonglong	print_exec_time
	)

private

Actually print the prepared summary to log.

Member Data Documentation

◆ aggregate_sctx

Security_context Slow_log_throttle::aggregate_sctx

private

We're using our own (empty) security context during summary generation.

That way, the aggregate value of the suppressed queries isn't printed with a specific user's name (i.e. the user who sent a query when or after the time-window closes), as that would be misleading.

◆ LOCK_log_throttle

mysql_mutex_t* Slow_log_throttle::LOCK_log_throttle

private

Slow_log_throttle is shared between THDs.

◆ log_summary

log_summary_t Slow_log_throttle::log_summary

private

The routine we call to actually log a line (our summary).

◆ rate

ulong* Slow_log_throttle::rate

private

A reference to the threshold ("no more than n log lines per ...").

References a (system-?) variable in the server.

◆ total_exec_time

ulonglong Slow_log_throttle::total_exec_time

private

Total of the execution times of queries in this time-window for which we suppressed logging.

For use in summary printing.

◆ total_lock_time

ulonglong Slow_log_throttle::total_lock_time

private

Total of the lock times of queries in this time-window for which we suppressed logging.

For use in summary printing.

The documentation for this class was generated from the following files:

sql/log.h
sql/log.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Slow_log_throttle()

Member Function Documentation

◆ flush()

◆ log()

◆ new_window()

◆ print_summary()

Member Data Documentation

◆ aggregate_sctx

◆ LOCK_log_throttle

◆ log_summary

◆ rate

◆ total_exec_time

◆ total_lock_time