Assuming your 22294's are being reported as the cause of the 1555's then you
probably need more space for deleted LOBs; but the pctversion relates to
percentage below current HWM of the LOB segment, but this does mean that if the
LOB segment has only recently started filling and has not yet reached steady
stats then 10% may be too small now, but will be sufficient in the future.
Broadly speaking there are usually no side effects to worry about with a larger
pctversion - except the section of the LOBINDEX relating to "reusable space"
can become that much larger.
Given that you're asking about pctversion I think you must be using basicfile
LOBs. Have you considered using RETENTION rather than PCTVERSION - this allows
the LOB segment to hold deleted LOBs until the time specified in the
undo_retention parameter has passed.
There are lots of things about LOBs that are not documented - including nasty
effects of concurrency and deletes/updates, and you might like to read the
short series in my blog on LOB problems in case anything I say there matches
your planned usage.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
@jloracle
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] on behalf
of Nik Tek [niktek2005@xxxxxxxxx]
Sent: 20 October 2016 20:19
To: ORACLE-L
Cc: Nik Tek
Subject: LOB Table - PCTVERSION 50%
Hi Oracle gurus,
I have a question, I'm noticing lot of ora-1555 and ora-22294 (snapshot too
old) errors.
The default value is 10% for PCTVERSION as you all know.
I was wondering if I can change the value to 50%, would this have any side
effects?
How do I measure if there a problem?
I could not find much of the information related to PCTVERSION for LOB tables.
--
Thank you
NikTeki
