onstat -l command: Print physical and logical log information
Use the onstat -l command to display information about the physical logs, logical logs, and temporary logical logs.
Example Output
Figure 1. onstat
-l command output
Physical Logging
Buffer bufused bufsize numpages numwrits pages/io
P-1 0 16 716 55 13.02
phybegin physize phypos phyused %used
1:263 500 270 0 0.00
Logical Logging
Buffer bufused bufsize numrecs numpages numwrits recs/pages pages/io
L-3 0 16 42169 2872 1043 14.7 2.8
Subsystem numrecs Log Space used
OLDRSAM 42169 4436496
address number flags uniqid begin size used %used
a517f70 1 U-B---- 1 1:763 500 500 100.00
a517fb0 2 U-B---- 2 1:1263 500 500 100.00
a40daf0 3 U-B---- 3 1:1763 500 500 100.00
a40db30 4 U-B---- 4 1:2263 500 500 100.00
a40db70 5 U-B---- 5 1:2763 500 500 100.00
a40dbb0 6 U---C-L 6 1:3263 500 372 74.40
a40dbf0 7 A------ 0 1:3763 500 0 0.00
a40dc30 8 A------ 0 1:4263 500 0 0.00
8 active, 8 total
Output description for the physical log files
The
first section of the display describes the physical-log configuration:
- buffer
- Is the number of the physical-log buffer
- bufused
- Is the number of pages of the physical-log buffer that are used
- bufsize
- Is the size of each physical-log buffer in pages
- numpages
- Is the number of pages written to the physical log
- numwrits
- Is the number of writes to disk
- pages/io
- Is calculated as numpages/numwrits
This value indicates how effectively physical-log writes are being buffered.
- phybegin
- Is the physical page number of the beginning of the log
- physize
- Is the size of the physical log in pages
- phypos
- Is the current position in the log where the next log-record write is to occur
- phyused
- Is the number of pages used in the log
- %used
- Is the percent of pages used
The second section of the onstat -l command
output describes the logical-log configuration:
- buffer
- Is the number of the logical-log buffer
- bufused
- Is the number of pages used in the logical-log buffer
- bufsize
- Is the size of each logical-log buffer in pages
- numrecs
- Is the number of records written
- numpages
- Is the number of pages written
- numwrits
- Is the number of writes to the logical log
- recs/pages
- Is calculated as numrecs/numpages
You cannot affect this value. Different types of operations generate different types (and sizes) of records.
- pages/io
- is calculated as numpages/numwrits
You can affect this value by changing the size of the logical-log buffer (specified as LOGBUFF in the ONCONFIG file) or by changing the logging mode of the database (from buffered to unbuffered, or vice versa).
The following fields are repeated for each
logical-log file:
- address
- Is the address of the log-file descriptor
- number
- Is logid number for the logical-log file
The logid numbers might be out of sequence because either the database server or administrator can insert a log file in-line.
- flags
- Provides the status of each log as follows:
- A
- Newly added (and ready to use)
- B
- Backed up
- C
- Current® logical-log file
- D
- Marked for deletion
To drop the log file and free its space for reuse, you must perform a level-0 backup of all storage spaces
- F
- Free, available for use
- L
- The most recent checkpoint record
- U
- Used
- uniqid
- Is the unique ID number of the log
- begin
- Is the beginning page of the log file
- size
- Is the size of the log in pages
- used
- Is the number of pages used
- %used
- Is the percent of pages used
- active
- Is the number of active logical logs
- total
- Is the total number of logical logs
Output description for temporary logical log files
The
database server uses temporary logical logs during a warm restore
because the permanent logs are not available then. The following fields
are repeated for each temporary logical-log file:
- address
- Is the address of the log-file descriptor
- number
- Is logid number for the logical-log file
- flags
- Provides the status of each log as follows:
- B
- Backed up
- C
- Current logical-log file
- F
- Free, available for use
- U
- Used
- uniqid
- Is the unique ID number of the log
- begin
- Is the beginning page of the log file
- size
- Is the size of the log in pages
- used
- Is the number of pages used
- %used
- Is the percent of pages used
- active
- Is the number of active temporary logical logs