Re: Insert into partitioned tables and specifying the partition name

  • From: amonte <ax.mount@xxxxxxxxx>
  • To: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
  • Date: Mon, 12 Apr 2010 00:12:07 +0200

Forget my last post, there were some problem with one of physical disks


2010/4/11 amonte <ax.mount@xxxxxxxxx>

> Hello
> Do you know why when dbwr and lgwr is writing (db file parallel write and
> log file parallel write) the whole system just freezes...?
> When we are loaidng data sometimes the load time increases from 4 minute to
> 20 and it happens when we observe this sort of "freeze", dbwr and lgwr busy
> writing. This can takes ñike 5 to 50 minutes
> 2010/4/10 Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
>> Autoextend is the other operation that can cause issues in this case.
>> I know there are bugs logged against this scenario, but as you
>> mentioned, the increment for the autoextend should be large enough
>> such that the allocation is infrequent (doing anything too frequently
>> when it can be avoided is a bad thing).
>> Personally I'm not a big fan of autoextend - I understand where/why it
>> can be desirable but I'd rather size out stuff by calculation and
>> monitor it and adjust as necessary.  That's not to say there is
>> anything wrong with it.
>> I think that bigfile is a fine idea, its just that there are certain
>> "corner/edge" cases where it can cause a little headache, and if using
>> RAC it can exacerbate this a bit.  The two specifically that come to
>> mind are
>> 1) autoextend increment being too small
>> 2) segment next extent being too small
>> Both of these put the file header block (block 2) in demand and when
>> there is only one file and one header block it can cause (undesired)
>> waits, however, making the next allocations large enough should
>> alleviate these issues.
>> The other issue that I am vaguely aware of is that RMAN is unable to
>> use parallelism for bigfile backups until 11.2 (IIRC).
>> On Sat, Apr 10, 2010 at 4:47 AM, amonte <ax.mount@xxxxxxxxx> wrote:
>> > After checking the datafile autoextend looks like it can cause the
>> problems
>> > I am seeing since the autoextend is set to 100M only. Just changed it to
>> > 512M. Will see how it affects the performance
>> >
>> > Finally is bigfile really a good idea in 10g?
>> --
>> Regards,
>> Greg Rahn

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