Re: log_checkpoint_timeout : what is exactly the meaning ?

The answer depends on your version of Oracle. Recently the meaning has changed - Oracle uses an incremental checkpoint strategy to ensure that the I/O subsystem is not flooded so ferociously at end of log file. The log_checkpoint_interval and log_checkpoint_timeout had their implementation changed so that they act as lag events, rather than triggering a checkpoint.

For log_checkpoint_timeout=900, you are telling Oracle not to ensure that no block may remain unwritten if its first change occurred more than 900 seconds ago.

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vigi98 wrote in message ...


>Hi all,

>

>In my init.ora, the only two parameters about checkpoints are the

>following :

>

>log_checkpoint_timeout = 900

>log_checkpoints_to_alert=true

>

>Shouldn't I observe in the alert file the beginning of a new

>checkpoint every 15 minutes ? Apparently checkpoints behave as if I

>had not set the log_checkpoint_timeout, i.e. checkpoints are launched

>only when a redo log switch occurs. As my redo logs are 200Mb wide,

>there can be a very long time before a redo log switch occurs, in case

>of low traffic on the database.

>

>Have I misunderstood the signification of this parameter (I mean

>log_checkpoint_timeout ) ?

>

>Thanks in advance.