Cannot allocate new log - Private strand flush not complete
Oracle Database Tips by Donald Burleson
October 19, 2015
Question: I just
upgraded to Oracle 10g release 2 and I keep getting this error
in my alert log
Thread 1 cannot
allocate new log, sequence 509
Private strand flush not complete
Current log# 2 seq# 508 mem# 0: /usr/local/o1_mf_2_2cx5wnw5_.log
What causes the "private strand
flush not complete" message?
Answer: This is not a
bug, it's the expected behavior in 10gr2. You can get the
message suppressed by increasing the
strand flush not complete" is a "noise" error, and can be
disregarded because it relates to internal cache redo file
management. It does not necessarily mean that you have a
problem, but it depends if the error message is accompanied by
You should check your transaction with used private redo size in the
x$ktifp fixed table
or why the DBWR wants to write these associated blocks so fast if you have a lot of "Private
strand flush not complete" messages.
This "private strand flush cannot complete" error is
sometimes accompanied by other errors/mistakes that cause a hung database.
Some DBA's blame a sub-optimal DBWR configuration for the
"private strand flush not complete" error. See
"DB_WRITER_PROCESSES" MOSC 67422.1, and "Understanding and
Tuning Buffer Cache and DBWR", MOSC Note: 62172.1.
Some DBA's note that this
error message can be caused by a too-full
datafile. Check your data file space, and add space to any
nearly full data files.
"strand" is a new
10gr2 term for redo latches. It notes that a strand is a
new mechanism to assign redo latches to multiple processes, and
it's related to the log_parallelism parameter. The
number of strands depends on the cpu_count.
When you switch redo logs you will
see this alert log message since all private strands have to be
flushed to the current redo log.
Oracle MOSC note 372557.1
Oracle Training from Don Burleson
The best on site
training classes" are just a phone call away! You can get personalized Oracle training by Donald Burleson, right at your shop!