Re: SECUREFILES disaster

From: Jonathan Lewis <>
Date: Sun, 13 May 2012 10:12:05 +0100
Message-ID: <>

"Jonathan Lewis" <> wrote in message
| "Mladen Gogala" <> wrote in message
|| Jonathan, I am not aware of any free space regulating mechanisms within
|| LOB segment. Within the table segment, there are free lists or the lists
|| of blocks with 25%,50% and 75% of used space, index segments have their
|| own mechanism, but no such things for LOB segments.
| I think this is a refernce back to my comment about extent-level
| contention - and you're right, i was thinking of bitmap space allocation
| when I wrote it, but the LOB space allocation is managed by the lobindex,
| of course.

Except I've realised that I wasn't right out of the ballpark in my original comments.

Although the LOBINDEX handles space management for space that is below the HWM, Oracle still has to have a mechanism to identify where the HWM is and which blocks have been prepared for use - which is why you have various bitmap blocks at the segment level when using tablespaces with freelist management, and why you still see the normal ASSM bitmap blocks even for LOB segments.


Jonathan Lewis
Oracle Core (Apress 2011)
Received on Sun May 13 2012 - 04:12:05 CDT

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