Force a checkpoint

When necessary, you can force a checkpoint with an onmode or SQL administration API command.

Force a checkpoint in any of the following situations:
  • To free a logical-log file that contains the most recent checkpoint record and that is backed up but not yet released (onstat -l status of U-B-L or U-B)
  • Before you issue onmode -sy to place the database server in quiescent mode
  • After building a large index, if the database server terminates before the next checkpoint. The index build restarts the next time that you restart the database server.
  • If a checkpoint has not occurred for a long time and you are about to attempt a system operation that might interrupt the database server
  • If foreground writes are taking more resources than you want (force a checkpoint to bring this down to zero temporarily)
  • Before you run dbexport or unload a table, to ensure physical consistency of all data before you export or unload it
  • After you perform a large load of tables using PUT or INSERT statements (Because table loads use the buffer cache, forcing a checkpoint cleans the buffer cache.)

To force a checkpoint, run onmode -c.

For information about using SQL administration API commands instead of some onmode commands, see Remote administration with the SQL administration API and the HCL Informix® Guide to SQL: Syntax.


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