Comments on: KGH: NO ACCESS allocations in V$SGASTAT – buffer cache within shared pool!

By: metin2 hileleri

metin2 hileleri — Mon, 01 Mar 2010 01:11:35 +0000

That’s fascinating stuff – cheers!

By: Pablo

Pablo — Thu, 10 Dec 2009 18:05:07 +0000

Really interesting post.
I came across the “KGH: NO ACCESS”
while writting a query to get shared pool sizes from AWR tables.
Initially was using DBA_HIST_SGASTAT, adding all components of the shared pool (initially after reading this post I ignored the KGH: NO ACCESS entry)
But the numbers didn’t match the ones in proper AWR reports.
I decided to check DBA_HIST_SHARED_POOL_ADVICE and realized that Oracle is getting the initial and end sized for the shared pool on AWR reports from there (at least the numbers match)
I wonder where is Oracle actually getting those…

By: Pure DBA Science – some good postings « ocpdba oracle weblog

Pure DBA Science – some good postings « ocpdba oracle weblog — Tue, 06 Oct 2009 17:18:54 +0000

[...] “KGH: NO ACCESS allocations in V$SGASTAT – buffer cache within shared pool!” – b… [...]

By: Undo,Redo and Buffer cache buffers all in SHARED POOL !!!! « Anand’s Blog

Fri, 18 Sep 2009 11:21:15 +0000

[...] http://blog.tanelpoder.com/2009/09/09/kgh-no-access-allocations-in-vsgastat-buffer-cache-within-shar... [...]

By: Bernard Polarski

Bernard Polarski — Fri, 18 Sep 2009 06:38:07 +0000

Just a quick feed back : We were using db_cache_size, sga_target and pga_aggregate_target.
shared_pool_size was unset. Given all the problems, I finally disabled ASSM and will not used it again 10.2.0.5 is out.

By: Log Buffer #161: a Carnival of the Vanities for DBAs « PlanetMysql.ru – информация о СУБД MySQL

Fri, 11 Sep 2009 19:59:15 +0000

[...] be stored inside shared pool. If you are curious about this fact, Tanel Poder delivers the proof in KGH: NO ACCESS allocations in V$SGASTAT – buffer cache within shared pool!. Heed the warning and do not run the examples in a production environment unless you want a posse [...]

By: Blogroll Report 04/09/2009 – 11/09/2009 « Coskan’s Approach to Oracle

Blogroll Report 04/09/2009 – 11/09/2009 « Coskan’s Approach to Oracle — Fri, 11 Sep 2009 18:29:39 +0000

[...] 8-Why buffer cache buffers can reside in shared pool and what are KGH NO ACCESS in shared pool? Tanel Poder -KGH: NO ACCESS allocations in V$SGASTAT – buffer cache within shared pool! [...]

By: Log Buffer #161: a Carnival of the Vanities for DBAs | Pythian Group Blog

Log Buffer #161: a Carnival of the Vanities for DBAs | Pythian Group Blog — Fri, 11 Sep 2009 17:50:45 +0000

By: Resizing the SGA « Oracle Scratchpad

Resizing the SGA « Oracle Scratchpad — Fri, 11 Sep 2009 15:27:27 +0000

[...] at the same time is memory in the shared pool being used for data blocks – as Tanel Poder has pointed out, when v$sgastat is showing memory in the class “KGH: NO ACCESS”, this is a case of [...]

By: Tanel Poder

Tanel Poder — Fri, 11 Sep 2009 12:15:40 +0000

No its something different. That note explains why there is db_block_buffers allocation in shared pool. This happens when you still use the old db_block_buffers init.ora parameter for setting buffer cache size – so the old (non-dynamic) buffer cache allocation method is used. When you use db_cache_size parameter, then the buffer headers (x$bh) memory is inside buffer cache granules themselves, thus there’s no need to allocate that memory from shared pool.