Any clues or oddities in v$sgastat - in particular any unfamiliar areas of the
shared pool that are unusually large.
Regards
Jonathan Lewis
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> on behalf
of Chris Taylor <christopherdtaylor1994@xxxxxxxxx>
Sent: 01 June 2018 01:40
To: GG
Cc: ORACLE-L
Subject: Re: Sudden occurrence of SHARED_POOL LATCH waits - DB up since 4/3/2018
Yeah I can't run that SQL either without locking up the shared pool on the db.
Chris
On Thu, May 31, 2018 at 1:29 PM, GG
<grzegorzof@xxxxxxxxxx<mailto:grzegorzof@xxxxxxxxxx>> wrote:
Hi,
You've got quite large shared pool, it is true that quering x$ksmsp is not
recommended due to excesive latch activity, but Oracle uses this query to
narrow down the shared pool issues:
SELECT * FROM ( SELECT ksmchidx subpool, 'DURATION:'||ksmchdur duration, 'CMNT:
'||ksmchcom cmnt, ksmchcls type, SUM(ksmchsiz) total_size, COUNT(*)
allocations, 'AVG:' avg,AVG(ksmchsiz) average_size, MIN(ksmchsiz) min_size,
'MAX:' max,MAX(ksmchsiz) max_size FROM x$ksmsp
GROUP BY ksmchidx, ksmchdur, ksmchcom, ksmchcls ORDER BY SUM(ksmchsiz))
WHERE (ROWNUM < 21 AND total_size > 10000 AND cmnt NOT LIKE 'CMNT:free%') OR
cmnt LIKE 'CMNT: free%'order by 3,4,1,2
/
Your problem could be related to subpool defragmentation which seems to be
often the case with exchange partition (generally partition maintenance?).
And indeed the shared pool can grow like crazy even when auto memory management
is inactive (_target parameters = 0), it is documented
SGA Re-Sizes Occurring Despite AMM/ASMM Being Disabled
(MEMORY_TARGET/SGA_TARGET=0) (Doc ID 1269139.1)
Check the resize ops like Tim said via query on :
V$MEMORY_RESIZE_OPS / V$SGA_RESIZE_OPS
Regards.
GG
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