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6

If your database is in simple recovery the log might be truncated after a checkpoint. This does not always occur though for reasons discussed in Factors That Can Delay Log Truncation (the most obvious being an open transaction) To see the inactive portion of the log you can use the undocumented DBCC log command. DBCC log(0,1) /*First parameter is ...


4

Yes, a thread in this case is the redo generated by an instance. If you had a 4-node RAC, you would have 4 redo threads. This is thread# in v$archived_log. The certain target is almost certainly referring to an SCN.


3

The transactions are not actually removed after a check point. Their state is only changed to inactive, so they are ignored by the fn_dblog function Even when the transactions are in the inactive parts of the online transaction log, it doesn't mean that they are deleted from the LDF file "the VLF is marked as truncated (meaning the VLF can be ...


3

If Resource Monitor says that SQL Server is actually performing the checkpoint (i.e., it's working okay, just that it's slow), all you can and should do is wait. If the disk subsystem is busy anyway (shared storage?), is it possible the other load has increased and now the I/O subsystem is near or at capacity? If you aren't measuring (recording) metrics ...


3

Use a database snapshot. Create a snapshot, do your worse. If things go ugly, revert to the snapshot, see Revert a Database to a Database Snapshot. Database snapshots are copy-on-write so they take almost no space on disk (the space taken will grow as you update the original db and the copy-on-write must save the previous data). They're fast to create and ...


3

Combing through the docs, I see the following (accidental incorrect details will hopefully (or surely) be pointed out by others): There is a separate server process called the background writer, whose function is to issue writes of "dirty" (new or modified) shared buffers. BW does its work according to its config parameters. It writes at most ...


1

I'm not completely certain, but I believe the "thread" in "thread checkpoint" refers to a DBWR thread/process. The "certain target" referenced is configurable; several init.ora parameters influence it, including: FAST_START_MTTR_TARGET LOG_CHECKPOINT_INTERVAL LOG_CHECKPOINT_TIMEOUT



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