Example output for backup performance monitoring
This topic presents an example of the output that is displayed from running the db2pd command with the -barstats option, for a running backup operation.
Each example section is followed by a table that provides detailed descriptions of the fields that appear in the results.
Examples
First, the agent or EDU identifiers for the backup operation are
displayed:
$ db2pd -db DBNAME1 -barstats 669
Printing out Backup Runtime Statistics at 2018-07-17-20.02.36.207705:
Backup Related EDUs:
---------------------------------------------------------------------
Backup agent ID: 669
BM 0 (EDU ID): db2bm.669.0 (75)
BM 1 (EDU ID): db2bm.669.1 (74)
BM 2 (EDU ID): db2bm.669.2 (73)
BM 3 (EDU ID): db2bm.669.3 (72)
MC 0 (EDU ID): db2med.669.0 (76)| Field | Description |
|---|---|
| Backup agent ID | Represents the EDU ID for the main backup agent, which coordinates the various backup EDUs. |
| BM N (EDU ID): db2bm.M.N | Represent the backup Buffer Manipulator EDU identifiers. These EDUs read data from the table space container files. In this example, there are four Buffer Manipulator EDUs, so the backup operation is running with a parallelism of four. |
| MC N (EDU ID): db2bm.M.N | Represent the backup Media Controller EDU identifiers. These EDUs write data to one or more backup image files. In this example, since only one backup image path is specified, the backup operation is using one media controller EDU. |
Next, information about each table space that is processed by the backup is
displayed:
Table Spaces to be Backed Up (appTblSpace):
---------------------------------------------------------------------
numEntry: 2
Table Spaces:
tblSpaceName: SYSCATSPACE
tblSpaceID: 0
tblSpaceType: 2
tblSpaceDataType: 0
tblSpaceSize: 15568 (in 4K pages)
nContainers: 1
backupInProgressTurnedOn: T
backupActiveIsSet: T
autoResizeLockAcquired: F
tblSpaceTotalPages: 16380
pageSize: 8192
extSize: 4
actualSize: 127533056
scanPages: T
backupLSN: 00000000000401DA
tblSpaceName: USERSPACE1
tblSpaceID: 2
tblSpaceType: 2
tblSpaceDataType: 32
tblSpaceSize: 1824 (in 4K pages)
nContainers: 1
backupInProgressTurnedOn: T
backupActiveIsSet: T
autoResizeLockAcquired: F
tblSpaceTotalPages: 4064
pageSize: 8192
extSize: 32
actualSize: 14942208
scanPages: T
backupLSN: 0000000000000000| Field | Description |
|---|---|
| tblSpaceName | The name of the table space. (See tablespace_name). |
| tblSpaceID | The table space ID. (See tablespace_id). |
| tblSpaceType | The table space type. (See tablespace_type). |
| tblSpaceDataType | The table space content type. (See tablespace_content_type). |
| tblSpaceSize | The table space usable size (number of 4 KB pages). (See tablespace_usable_pages). |
| nContainers | The number of table space containers. (See tablespace_num_containers). |
| backupInProgressTurnedOn | A flag that indicates whether a backup of this table space is in progress. This flag is turned off when all pages have been read for the backup. It is used internally by Db2 to alter the behavior of certain table space container operations to maintain data integrity. |
| backupActiveIsSet | A flag that indicates whether a backup is active for this table space. This flag is turned off at the very end of the backup. It protects against running two simultaneous backups on the same table space. |
| extentMovementLockAcquired | Indicates whether the extent movement lock has been acquired for this table space. |
| autoResizeLockAcquired | A flag that indicates whether the table space auto-resize lock is acquired. The lock prevents a table space auto resize operation from occurring while the online backup is running. |
| tblSpaceTotalPages | The total size of the table space, including unusable meta pages (number of 4 KB pages). (See tablespace_total_pages). |
| pageSize | The size of a page for the table space (in bytes). (See tablespace_page_size). |
| extSize | The number of pages that constitute an extent for the table space (in pages). (See tablespace_extent_size). |
| actualSize | The table space total size (in bytes). |
| scanPages | A flag that indicates the need for table space page scanning for an incremental backup operation. |
| backupLSN | The Log Sequence Number for the backup operation on the table space. |
Next, an ordered list of table space processing states is displayed:
Table Space Queue:
[0]
tblSpaceName: TBSP
tblSpaceID: 3
backupStatus: in progress
Being backed up by: db2bm.18.0
Object being backed up: DMS.TABLESPACE.DATA
Number of pages already backed up: 524288
Total number of pages in table space: 3702752
[1]
tblSpaceName: SYSCATSPACE
tblSpaceID: 0
backupStatus: complete
[2]
tblSpaceName: USERSPACE1
tblSpaceID: 2
backupStatus: pending
The next table space to be backed up:
[2]
tblSpaceName: USERSPACE1
tblSpaceID: 2
backupStatus: pending
| Field | Description |
|---|---|
| backupStatus | The status of processing for the table space. Possible values are:
|
| Being backed up by | The Buffer Manipulator EDU that is assigned to read the contents of this table space. |
| Object being backed up | The type of data currently being processed. |
| Number of pages already backed up | The number of pages in the table space already processed. |
| Total number of pages in table space | The total number of pages in the table space. |
Next, backup performance statistical information is displayed. The displayed values are
aggregated up to the time of collection. Final information is displayed in the Db2® diagnostic log,
db2diag.log, upon completion of the backup operation. Interpretation of this
statistical information can be aided by existing resources, such as Backup and Restore Statistics or Understanding and Tuning DB2/LUW Backup and Restore
Performance.
Performance statistics:
---------------------------------------------------------------------
Parallelism = 4
Number of buffers = 4
Buffer size = 6557696 (1601 4kB pages)
BM# Total I/O MsgQ WaitQ Buffers Bytes
--- -------- -------- -------- -------- -------- --------
000 116.11 0.00 0.00 34.18 1 98304
001 116.11 0.00 0.00 40.62 0 0
002 116.10 0.00 0.00 40.63 0 0
003 116.09 0.00 0.00 40.69 0 0
--- -------- -------- -------- -------- -------- --------
TOT 464.42 0.00 0.00 156.14 1 98304
MC# Total I/O MsgQ WaitQ Buffers Bytes
--- -------- -------- -------- -------- -------- --------
000 116.11 0.01 28.38 32.12 2 6561792
--- -------- -------- -------- -------- -------- --------
TOT 116.11 0.01 28.38 32.12 2 6561792
| Field | Description |
|---|---|
| BM# | The Buffer Manipulator EDU identifier. |
| MC# | The Media Controller EDU identifier. |
| Total | The total elapsed time that this EDU has been in backup processing, in seconds. |
| I/O | The amount of time that this EDU spent either reading or writing data, in seconds. |
| MsgQ | The amount of time that the EDU spent waiting to get a buffer, in seconds. For backup operations, the Buffer Manipulator EDUs wait for an empty buffer to fill with data from the table space. The Media Controller EDUs wait for a full buffer and then write the buffer out to the backup image file. |
| WaitQ | Time spent waiting for a state machine control message, in seconds. When a Buffer Manipulator EDU has no more table spaces to process, the WaitQ value increases, while other Buffer Manipulators continue to process their table spaces. |
| Buffers | The total number of I/O buffers that were processed by this EDU. |
| Bytes | The quantity of data that was processed by this EDU. The column header can also be displayed as KBytes or MBytes depending on the quantity of data processed. |
Next, size estimate information is displayed:
Size estimates:
---------------------------------------------------------------------
Total size estimate (bytes): 173981696
Pre-adjusted total size estimate (bytes): 173981696
Init data estimate (bytes): 1492516
User data estimate (bytes): 159252480
End data estimate (bytes): 25624
Size estimate for MC1 (bytes): 173981696
Size estimate for remaining MCs (bytes): 172408832
| Field | Description |
|---|---|
| Total size estimate (bytes) | An estimate of the total amount of data to process during the backup operation. |
| Pre-adjusted total size estimate (bytes) | An estimate of the total amount of data to process during the backup operation. |
| Init data estimate (bytes) | An estimate of the size of database meta information to be included at the beginning of the backup image. |
| User data estimate (bytes) | An estimate of the size of table space container data to be included in the backup image. |
| End data estimate (bytes) | An estimate of the size of database meta information to be included at the end of the backup image. |
| Size estimate for MC1 (bytes) | An estimate of the amount of data processed by Media Controller 1, which includes the database meta information. |
| Size estimate for remaining MCs (bytes) | An estimate of the amount of data processed by all other Media Controllers. |
Next, current work progress information is displayed:
Progress Monitor:
---------------------------------------------------------------------
Phase #: 1 of 1
Total work units (bytes): 160774322
Completed work units (bytes): 1496218Next, the time that is required to flush (persist) changed pages from one or more buffer pools
into stable storage are displayed.
Note: Database and table space flushing semantics are beyond the
scope of this document.
Also, the time that is required to update the database history file
and table space change history meta information is displayed, along with log file processing
information (when the online backup INCLUDE LOGS option was
specified).Other Backup Statistics:
---------------------------------------------------------------------
Database bufferpool flushing time: 0.18 seconds
Table space bufferpool flushing time 1: 0.02 seconds
Table space bufferpool flushing time 2: 0.72 seconds
Table space bufferpool flushing time 3: Not Recorded
Database recovery history file (db2rhist.asc) elapsed processing time: 0.27 seconds
Table space change history file (db2tschg.his) elapsed processing time: 0.08 seconds
Processed 9 of 100 database recovery logs.
Database recovery logs elapsed processing time: 3.10 secondsAnd lastly, when the automatic pruning of recovery objects is enabled (that is,
AUTO_DEL_REC_OBJ database configuration parameter is enabled), additional
information is displayed about
pruning.
Database Recovery History File Pruning Statistics:
---------------------------------------------------------------------
Auto deletion of recovery objects (AUTO_DEL_REC_OBJ): ON
Number of database backups to retain (NUM_DB_BACKUPS): 1
Recovery history retention (days) (REC_HIS_RETENTN): 0
Status: In progress
Elapsed processing time: 27.60 seconds
Number of entries pruned: 1
Number of objects deleted: 408
Current state: Deleting
Object Details:
Objpart: 20180720150330001
Operation: B
Location: adsm/libtsm.a
Vendor State Info:
startTime: 20180720164749
function: sqluvdel
| Field | Description |
|---|---|
| Status | The status of the recovery object pruning, if enabled. Possible values are:
|
| Processing time | The time spent pruning expired recovery objects. |
| Number of entries pruned | The current number of recovery history file entries pruned. |
| Number of objects deleted | The current number of expired recovery objects (backup images, log files) that have been deleted. |
| Current state | The current state of object deletion or pruning: Possible values are:
|
| Object details | Various (internal) details about the recovery object currently being processed. |