log file switch (checkpoint incomplete)

[harshal patil]

Hii
My database showing log file switch (checkpoint incomplete) for one
query what is the reason?
query is update for one schema

[ddf]

On Oct 16, 8:33 am, harshal patil <patilharsh...@gmail.com> wrote:
> Hii
> My database showing log file switch (checkpoint incomplete) for one
> query what is the reason?

A checkpoint occurs at every log switch. If a previous checkpoint is
already in progress, the checkpoint forced by the log switch will
override the current checkpoint. This is why the '(checkpoint
incomplete)' message occurs. This is NOT a problem.

> query is update for one schema

David Fitzjarrell

[ExpertDba]

This message indicates that Oracle wants to reuse a redo log file, but
the current checkpoint position is still in that log. In this case,
Oracle must wait until the checkpoint position passes that log,
Because the incremental checkpoint target never lags the current log
tail by more than 90% of the smallest log file size, this situation
may be encountered if DBWR writes too slowly, or if a log switch
happens before the log is completely full, or if log file sizes are
too small.
When the database waits on checkpoints,redo generation is stopped
until the log switch is done.

Some ways to resolve incomplete checkpoints is through tuning
checkpoints and logs:

1) Give the checkpoint process more time to cycle through the logs
- add more redo log groups
- increase the size of the redo logs
2) Reduce the frequency of checkpoints
- increase LOG_CHECKPOINT_INTERVAL
- increase size of online redo logs
3) Improve the efficiency of checkpoints enabling the CKPT process
with CHECKPOINT_PROCESS=TRUE
4) Set LOG_CHECKPOINT_TIMEOUT = 0. This disables the
checkpointing based on
time interval.
Another means of solving this error is for DBWR to quickly write the
dirty buffers on disk. The parameter linked to this task is:
DB_BLOCK_CHECKPOINT_BATCH.

Check Metalink or google up a bit more.

-regards,
Channesh