This section describes options for monitoring cloning operations.
A cloning operation may take some time to complete, depending
on the amount of data and other factors related to data
transfer. You can monitor the status and progress of a cloning
operation on the recipient MySQL server instance using the
clone_status
and
clone_progress
Performance Schema
tables.
The clone_status
and
clone_progress
Performance
Schema tables can be used to monitor a cloning operation on
the recipient MySQL server instance only. To monitor a
cloning operation on the donor MySQL server instance, use
the clone stage events, as described in
Monitoring Cloning Operations Using Performance Schema Stage Events.
The
clone_status
table provides the state of the current or last executed cloning operation. A clone operation has four possible states:Not Started
,In Progress
,Completed
, andFailed
.The
clone_progress
table provides progress information for the current or last executed clone operation, by stage. The stages of a cloning operation includeDROP DATA
,FILE COPY
,PAGE_COPY
,REDO_COPY
,FILE_SYNC
,RESTART
, andRECOVERY
.
The SELECT
and
EXECUTE
privileges on the
Performance Schema is required to access the Performance
Schema clone tables.
To check the state of a cloning operation:
Connect to the recipient MySQL server instance.
Query the
clone_status
table:mysql> SELECT STATE FROM performance_schema.clone_status; +-----------+ | STATE | +-----------+ | Completed | +-----------+
Should a failure occur during a cloning operation, you can
query the clone_status
table for
error information:
mysql> SELECT STATE, ERROR_NO, ERROR_MESSAGE FROM performance_schema.clone_status;
+-----------+----------+---------------+
| STATE | ERROR_NO | ERROR_MESSAGE |
+-----------+----------+---------------+
| Failed | xxx | "xxxxxxxxxxx" |
+-----------+----------+---------------+
To review the details of each stage of a cloning operation:
Connect to the recipient MySQL server instance.
Query the
clone_progress
table. For example, the following query provides state and end time data for each stage of the cloning operation:mysql> SELECT STAGE, STATE, END_TIME FROM performance_schema.clone_progress; +-----------+-----------+----------------------------+ | stage | state | end_time | +-----------+-----------+----------------------------+ | DROP DATA | Completed | 2019-01-27 22:45:43.141261 | | FILE COPY | Completed | 2019-01-27 22:45:44.457572 | | PAGE COPY | Completed | 2019-01-27 22:45:44.577330 | | REDO COPY | Completed | 2019-01-27 22:45:44.679570 | | FILE SYNC | Completed | 2019-01-27 22:45:44.918547 | | RESTART | Completed | 2019-01-27 22:45:48.583565 | | RECOVERY | Completed | 2019-01-27 22:45:49.626595 | +-----------+-----------+----------------------------+
For other clone status and progress data points that you can monitor, refer to Section 29.12.19, “Performance Schema Clone Tables”.
A cloning operation may take some time to complete, depending
on the amount of data and other factors related to data
transfer. There are three stage events for monitoring the
progress of a cloning operation. Each stage event reports
and
WORK_COMPLETED
values.
Reported values are revised as the operation progresses.
WORK_ESTIMATED
This method of monitoring a cloning operation can be used on the donor or recipient MySQL server instance.
In order of occurrence, cloning operation stage events include:
stage/innodb/clone (file copy)
: Indicates progress of the file copy phase of the cloning operation.
andWORK_ESTIMATED
units are file chunks. The number of files to be transferred is known at the start of the file copy phase, and the number of chunks is estimated based on the number of files.WORK_COMPLETED
WORK_ESTIMATED
is set to the number of estimated file chunks.WORK_COMPLETED
is updated after each chunk is sent.stage/innodb/clone (page copy)
: Indicates progress of the page copy phase of cloning operation.WORK_ESTIMATED
andWORK_COMPLETED
units are pages. Once the file copy phase is completed, the number of pages to be transferred is known, andWORK_ESTIMATED
is set to this value.WORK_COMPLETED
is updated after each page is sent.stage/innodb/clone (redo copy)
: Indicates progress of the redo copy phase of cloning operation.WORK_ESTIMATED
andWORK_COMPLETED
units are redo chunks. Once the page copy phase is completed, the number of redo chunks to be transferred is known, andWORK_ESTIMATED
is set to this value.WORK_COMPLETED
is updated after each chunk is sent.
The following example demonstrates how to enable
stage/innodb/clone%
event instruments and
related consumer tables to monitor a cloning operation. For
information about Performance Schema stage event instruments
and related consumers, see
Section 29.12.5, “Performance Schema Stage Event Tables”.
Enable the
stage/innodb/clone%
instruments:mysql> UPDATE performance_schema.setup_instruments SET ENABLED = 'YES' WHERE NAME LIKE 'stage/innodb/clone%';
Enable the stage event consumer tables, which include
events_stages_current
,events_stages_history
, andevents_stages_history_long
.mysql> UPDATE performance_schema.setup_consumers SET ENABLED = 'YES' WHERE NAME LIKE '%stages%';
Run a cloning operation. In this example, a local data directory is cloned to a directory named
cloned_dir
.mysql> CLONE LOCAL DATA DIRECTORY = '/path/to/cloned_dir';
Check the progress of the cloning operation by querying the Performance Schema
events_stages_current
table. The stage event shown differs depending on the cloning phase that is in progress. TheWORK_COMPLETED
column shows the work completed. TheWORK_ESTIMATED
column shows the work required in total.mysql> SELECT EVENT_NAME, WORK_COMPLETED, WORK_ESTIMATED FROM performance_schema.events_stages_current WHERE EVENT_NAME LIKE 'stage/innodb/clone%'; +--------------------------------+----------------+----------------+ | EVENT_NAME | WORK_COMPLETED | WORK_ESTIMATED | +--------------------------------+----------------+----------------+ | stage/innodb/clone (redo copy) | 1 | 1 | +--------------------------------+----------------+----------------+
The
events_stages_current
table returns an empty set if the cloning operation has finished. In this case, you can check theevents_stages_history
table to view event data for the completed operation. For example:mysql> SELECT EVENT_NAME, WORK_COMPLETED, WORK_ESTIMATED FROM events_stages_history WHERE EVENT_NAME LIKE 'stage/innodb/clone%'; +--------------------------------+----------------+----------------+ | EVENT_NAME | WORK_COMPLETED | WORK_ESTIMATED | +--------------------------------+----------------+----------------+ | stage/innodb/clone (file copy) | 301 | 301 | | stage/innodb/clone (page copy) | 0 | 0 | | stage/innodb/clone (redo copy) | 1 | 1 | +--------------------------------+----------------+----------------+
Performance Schema provides instrumentation for advanced performance monitoring of clone operations. To view the available clone instrumentation, and issue the following query:
mysql> SELECT NAME,ENABLED FROM performance_schema.setup_instruments
WHERE NAME LIKE '%clone%';
+---------------------------------------------------+---------+
| NAME | ENABLED |
+---------------------------------------------------+---------+
| wait/synch/mutex/innodb/clone_snapshot_mutex | NO |
| wait/synch/mutex/innodb/clone_sys_mutex | NO |
| wait/synch/mutex/innodb/clone_task_mutex | NO |
| wait/synch/mutex/group_rpl/LOCK_clone_donor_list | NO |
| wait/synch/mutex/group_rpl/LOCK_clone_handler_run | NO |
| wait/synch/mutex/group_rpl/LOCK_clone_query | NO |
| wait/synch/mutex/group_rpl/LOCK_clone_read_mode | NO |
| wait/synch/cond/group_rpl/COND_clone_handler_run | NO |
| wait/io/file/innodb/innodb_clone_file | YES |
| stage/innodb/clone (file copy) | YES |
| stage/innodb/clone (redo copy) | YES |
| stage/innodb/clone (page copy) | YES |
| statement/abstract/clone | YES |
| statement/clone/local | YES |
| statement/clone/client | YES |
| statement/clone/server | YES |
| memory/innodb/clone | YES |
| memory/clone/data | YES |
+---------------------------------------------------+---------+
Wait Instruments
Performance schema wait instruments track events that take time. Clone wait event instruments include:
wait/synch/mutex/innodb/clone_snapshot_mutex
: Tracks wait events for the clone snapshot mutex, which synchronizes access to the dynamic snapshot object (on the donor and recipient) between multiple clone threads.wait/synch/mutex/innodb/clone_sys_mutex
: Tracks wait events for the clone sys mutex. There is one clone system object in a MySQL server instance. This mutex synchronizes access to the clone system object on the donor and recipient. It is acquired by clone threads and other foreground and background threads.wait/synch/mutex/innodb/clone_task_mutex
: Tracks wait events for the clone task mutex, used for clone task management. Theclone_task_mutex
is acquired by clone threads.wait/io/file/innodb/innodb_clone_file
: Tracks all I/O wait operations for files that clone operates on.
For information about monitoring InnoDB
mutex waits, see
Section 17.16.2, “Monitoring InnoDB Mutex Waits Using Performance Schema”.
For information about monitoring wait events in general, see
Section 29.12.4, “Performance Schema Wait Event Tables”.
Stage Instruments
Performance Schema stage events track steps that occur during the statement-execution process. Clone stage event instruments include:
stage/innodb/clone (file copy)
: Indicates progress of the file copy phase of the cloning operation.stage/innodb/clone (redo copy)
: Indicates progress of the redo copy phase of cloning operation.stage/innodb/clone (page copy)
: Indicates progress of the page copy phase of cloning operation.
For information about monitoring cloning operations using stage events, see Monitoring Cloning Operations Using Performance Schema Stage Events. For general information about monitoring stage events, see Section 29.12.5, “Performance Schema Stage Event Tables”.
Statement Instruments
Performance Schema statement events track statement execution.
When a clone operation is initiated, the different statement
types tracked by clone statement instruments may be executed
in parallel. You can observe these statement events in the
Performance Schema statement event tables. The number of
statements that execute depends on the
clone_max_concurrency
and
clone_autotune_concurrency
settings.
Clone statement event instruments include:
statement/abstract/clone
: Tracks statement events for any clone operation before it is classified as a local, client, or server operation type.statement/clone/local
: Tracks clone statement events for local clone operations; generated when executing aCLONE LOCAL
statement.statement/clone/client
: Tracks remote cloning statement events that occur on the recipient MySQL server instance; generated when executing aCLONE INSTANCE
statement on the recipient.statement/clone/server
: Tracks remote cloning statement events that occur on the donor MySQL server instance; generated when executing aCLONE INSTANCE
statement on the recipient.
For information about monitoring Performance Schema statement events, see Section 29.12.6, “Performance Schema Statement Event Tables”.
Memory Instruments
Performance Schema memory instruments track memory usage. Clone memory usage instruments include:
memory/innodb/clone
: Tracks memory allocated byInnoDB
for the dynamic snapshot.memory/clone/data
: Tracks memory allocated by the clone plugin during a clone operation.
For information about monitoring memory usage using Performance Schema, see Section 29.12.20.10, “Memory Summary Tables”.
The
Com_clone
status variable provides a count of
CLONE
statement executions.
For more information, refer to the discussion about
Com_xxx
statement counter variables in
Section 7.1.10, “Server Status Variables”.