log_sink_perfschema.h File Reference

This file contains. More...

#include "log_builtins_internal.h"
#include "my_thread_local.h"

Go to the source code of this file.

Classes
struct	_log_sink_pfs_event

Macros
#define	LOG_SINK_PFS_ERROR_CODE_LENGTH   10
#define	LOG_SINK_PFS_SUBSYS_LENGTH   7

Typedefs
typedef struct _log_sink_pfs_event	log_sink_pfs_event

Functions
void	log_sink_pfs_read_start ()
	Acquire a read-lock on the ring-buffer. More...
void	log_sink_pfs_read_end ()
	Release read-lock on ring-buffer. More...
size_t	log_sink_pfs_event_count ()
	Get number of events currently in ring-buffer. More...
log_sink_pfs_event *	log_sink_pfs_event_first ()
	Get oldest event still in ring-buffer. More...
log_sink_pfs_event *	log_sink_pfs_event_next (log_sink_pfs_event *e)
	Get event following the supplied one. More...
log_sink_pfs_event *	log_sink_pfs_event_valid (log_sink_pfs_event *e, ulonglong logged)
	Use timestamp to check whether a given event-pointer still points to a valid event in the ring-buffer. More...
int	log_error_read_log_init ()
	Set up ring-buffer for error-log. More...
int	log_error_read_log_exit ()
	Release error log ring-buffer. More...
log_service_error	log_error_read_log (const char *log_name)
	Restore error log messages from previous shutdown. More...
log_service_error	log_sink_pfs_event_add (log_sink_pfs_event *e, const char *blob_src)
	Add a log-event to the ring buffer. More...
int	log_sink_perfschema (void *instance, log_line *ll)
	services: log sinks: logging to performance_schema ring-buffer More...

Variables
ulong	log_sink_pfs_buffered_bytes
	bytes in use (now) More...
ulong	log_sink_pfs_buffered_events
	events in buffer (now) More...
ulong	log_sink_pfs_expired_events
	number of expired entries (ever) More...
ulong	log_sink_pfs_longest_event
	longest event seen (ever) More...
ulonglong	log_sink_pfs_latest_timestamp
	timestamp of most recent write More...

Detailed Description

This file contains.

a) The API for the reading of previously written error logs. (These functions will in turn use a parse-function defined in a log-sink. Whichever log-sink that has a parse-function is listed first in @global.log_error_services will be used; that service will decide what log-file to read (i.e. its name) and how to parse it. We initially support the reading of JSON- formatted error log files and of the traditional MySQL error log files.) This lets us restore error log information from previous runs when the server starts. These functions are called from mysqld.cc at start-up.

b) The log-sink that adds errors logged at run-time to the ring-buffer (to be called from

See also

log_line_submit() during normal operation, i.e. when loadable log-components are available, connections are accepted, and so on).

Macro Definition Documentation

LOG_SINK_PFS_ERROR_CODE_LENGTH

#define LOG_SINK_PFS_ERROR_CODE_LENGTH   10

LOG_SINK_PFS_SUBSYS_LENGTH

#define LOG_SINK_PFS_SUBSYS_LENGTH   7

Typedef Documentation

log_sink_pfs_event

typedef struct _log_sink_pfs_event log_sink_pfs_event

Function Documentation

log_error_read_log()

log_service_error log_error_read_log

(

const char *

log_name

)

Restore error log messages from previous shutdown.

We try restoring from the first (leftmost) of those services listed in @global.log_error_services that have the LOG_SERVICE_LOG_PARSER characteristic.

It is assumed that the last run's log file name is the same as the current one's. That is to say, we check whether the file supplied to –log-error already exists.

Once we have determined what file to read from, we'll call

See also

log_error_read_loop() to do the actual reading and parsing.

It should be noted that at the point this function is normally called, buffered error logging will not have flushed yet.

a) If we are using the built-in "trad" sink/reader, the start-up messages are usually not buffered, and have already been written to the error log. In this case, they will be restored from the log (and flushing won't add another event to the ring-buffer).

b) If we are using a reader in a loadable log-service,

Parameters

log_name

The log file to read (log_error_dest).

Return values

LOG_SERVICE_SUCCESS	Success (log read and parsed)
LOG_SERVICE_UNABLE_TO_READ	Could not read/access() file
LOG_SERVICE_INVALID_ARGUMENT	Invalid file-name (no '.')
LOG_SERVICE_NOT_AVAILABLE	No log_component active that can parse log-files
LOG_SERVICE_ARGUMENT_TOO_LONG	File-name too long
LOG_SERVICE_COULD_NOT_MAKE_LOG_NAME	Could not determine file extension
otherwise	Return value from reader

log_error_read_log_exit()

int log_error_read_log_exit

(

)

Release error log ring-buffer.

Returns

0 Success - buffer was released, or did not exist in the first place.

Return values

0	Success - buffer was released, or did not exist in the first place.

log_error_read_log_init()

int log_error_read_log_init

(

)

Set up ring-buffer for error-log.

Returns

0 Success - buffer was allocated.

!=0 Failure - buffer was not allocated.

Return values

0	Success - buffer was allocated.
!=0	Failure - buffer was not allocated.

log_sink_perfschema()

int log_sink_perfschema	(	void *	instance,
		log_line *	ll
	)

services: log sinks: logging to performance_schema ring-buffer

Will write timestamp, label, thread-ID, and message to stderr/file. If you should not be able to specify a label, one will be generated for you from the line's priority field.

Parameters

instance	instance handle
ll	the log line to write

Return values

int	number of added fields, if any

log_sink_pfs_event_add()

log_service_error log_sink_pfs_event_add	(	log_sink_pfs_event *	e,
		const char *	blob_src
	)

Add a log-event to the ring buffer.

In the ring-buffer, each event exists as a header and a blob. The header is a log_sink_pfs_event struct containing the traditional error-log columns. It is followed by a variable-length blob that contains just the message string in traditional log mode, and the complete event as JSON in JSON log format. The length of the event will be align to the correct boundary.

If writing the event would go past the end of the ring-buffer, we wrap around to the beginning of the buffer.

After the function success, ring_buffer_read will be set to a valid, non-zero value.

Parameters

e	filled-in event struct to copy into the ring-buffer
blob_src	variable-length part of the event to add to the ring-buffer

Return values

LOG_SERVICE_SUCCESS	event was added
LOG_SERVICE_NOT_AVAILABLE	ring-buffer not available
LOG_SERVICE_INVALID_ARGUMENT	event has no message
LOG_SERVICE_ARGUMENT_TOO_LONG	event is larger than buffer(!)

log_sink_pfs_event_count()

size_t log_sink_pfs_event_count

(

)

Get number of events currently in ring-buffer.

Caller should hold THR_LOCK_log_perschema when reading this.

Returns

number of events current in ring-buffer (0..)

log_sink_pfs_event_first()

log_sink_pfs_event * log_sink_pfs_event_first

(

)

Get oldest event still in ring-buffer.

Caller should hold read-lock on THR_LOCK_log_perfschema when calling this.

Returns

nullptr No events in buffer

otherwise Address of oldest event in ring-buffer

Caller should hold read-lock on THR_LOCK_log_perfschema when calling this.

Return values

nullptr	No events in buffer
otherwise	Address of oldest event in ring-buffer

log_sink_pfs_event_next()

log_sink_pfs_event * log_sink_pfs_event_next

(

log_sink_pfs_event *

e

)

Get event following the supplied one.

Caller should hold read-lock on THR_LOCK_log_perfschema when calling this.

If advancing the read position puts the read-pointer beyond the highest-address event in the ring-buffer (which isn't necessarily the latest event, which is defined as the last event before catching up with the write-pointer), i.e. at a position where either a wrap- around marker exists, or there is not enough space for a header, we wrap around to the start of the ring-buffer.

Parameters

e	Last event the caller was processing. This event should be valid, non-NULL, and should not be a wrap-around marker (m_messages_length == 0).

Return values

nullptr	No more events in ring-buffer (caught up with writer)
otherwise	Address of the next event in the ring-buffer

log_sink_pfs_event_valid()

log_sink_pfs_event * log_sink_pfs_event_valid	(	log_sink_pfs_event *	e,
		ulonglong	logged
	)

Use timestamp to check whether a given event-pointer still points to a valid event in the ring-buffer.

Caller should hold read-lock on THR_LOCK_log_perfschema when calling this.

Parameters

e	Address of event
logged	unique timestamp of event

Return values

nullptr	Event no longer exists in ring-buffer
otherwise	Address of the event in the ring-buffer

log_sink_pfs_read_end()

void log_sink_pfs_read_end

(

)

Release read-lock on ring-buffer.

log_sink_pfs_read_start()

void log_sink_pfs_read_start

(

)

Acquire a read-lock on the ring-buffer.

Variable Documentation

log_sink_pfs_buffered_bytes

ulong log_sink_pfs_buffered_bytes

extern

bytes in use (now)

log_sink_pfs_buffered_events

ulong log_sink_pfs_buffered_events

extern

events in buffer (now)

log_sink_pfs_expired_events

ulong log_sink_pfs_expired_events

extern

number of expired entries (ever)

log_sink_pfs_latest_timestamp

ulonglong log_sink_pfs_latest_timestamp

extern

timestamp of most recent write

log_sink_pfs_longest_event

ulong log_sink_pfs_longest_event

extern

longest event seen (ever)