Using Command-Line Utilities

You can use the following command-line utilities to obtain information about the physical-log file.

onstat -l

The first line of the onstat -l output displays the following information for each physical-log buffer:

• The number of buffer pages used (bufused)
• The size of each physical log buffer in pages (bufsize)
• The number of pages written to the buffer (numpages)
• The number of writes from the buffer to disk (numwrits)
• The ratio of pages written to the buffer to the number of writes to disk (pages/IO)

The second line of the onstat -l output displays the following information about the physical log:

• The page number of the first page in the physical-log file (phybegin)
• The size of the physical-log file (physize)
• The current position in the log where the next write occurs (physpos)
• The number of pages in the log that have been used (phyused)
• The percentage of the total physical-log pages that have been used (%used)

The third line of the onstat -l output displays the following information about each logical-log buffer:

• The number of buffer pages used (bufused)
• The size of each logical-log buffer in pages (bufsize)
• The number of records written to the buffer (numrecs)
• The number of pages written to the buffer (numpages)
• The number of writes from the buffer to disk (numwrits)
• The ratio of records to pages in the buffer (recs/pages)
• The ratio of pages written to the buffer to the number of writes to disk (pages/IO)

Figure 89 shows sample output from the onstat -l option that contains the relevant fields.

Physical Logging
Buffer bufused  bufsize  numpages numwrits pages/io
  P-2  0        16       110      10       11.00
      phybegin physize  phypos   phyused  %used
      10003f   500      233      0        0.00

Logical Logging
Buffer bufused  bufsize  numrecs  numpages numwrits recs/pages pages/io
  L-1  0        16       3075     162      75       19.0       2.2
...

onutil CHECK RESERVED DISPLAY

The database server stores the physical-log file information in those reserved pages dedicated to checkpoint information (PAGE_1CKPT and PAGE_2CKPT). You can view the checkpoint reserve pages with the onutil CHECK RESERVED command with the DISPLAY option. The reserve pages contain the state of the physical log at the last checkpoint. Figure 90 shows an example of the relevant output.

Validating Informix database server reserved pages - PAGE_1CKPT & PAGE_2CKPT
          Using check point page PAGE_2CKPT.

    Time stamp of checkpoint       16024
    Time of checkpoint             07/30/99 09:34:33
    Physical log begin address     10003f
    Physical log size              500
    Physical log position at Ckpt  e9
...