11.2 space pre-allocation algorithm
- From: Venkat Krish <venkat.lear@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 23 Mar 2016 16:14:42 -0400
Hi-
Running into this weird problem & just wanted to check if anyone else had
encountered the same.
DB Version: 11.2.0.4
Env: Test env ( Write intensive load)
Sudden surge of inserts into a segment ( each day is a diff partition),
sometime causes the segment to grow rapidly to the point it affects the
inserts themselves ( manifesting as "HW contention")
I have read MOS ID : 743773.1 & have had pre-alloc algorithm disabled a
long back
"_enable_space_preallocation" is set to 0
tablespace is bigfile tablespace & at the time of this weirdness, I noticed
that tablespace % usage was just around 80% when this weirdness started.
Any pointers on where to look at ?
or
Anyone knows what internal data , Oracle looks at segment/table and
decides to allocate space proactively based & how it arrives at the size to
extend?
--tablespace info
TOTAL_GB FREE_GB
-------- --------
650 130 <-- when problem started
...
650 43 <-- when problem ended. ( >1 hour of segment growth)
--segment info
dba_segments (size in GB) for that segment+ partition
SIZE_GB
-------
16.31G <-- problem started
...
97.37G <-- when allocation ended
(segment has only data incoming..no deletes or updates)
Thanks in adv,
Venkat
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