Re: READ wait events when inserting data into a CLOB

  • From: Tanel Poder <tanel@xxxxxxxxxxxxxx>
  • To: Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx>
  • Date: Sat, 8 Dec 2012 22:46:10 +0200

And that should apply to the write-write contention the same way... (and
again it's the LOB-segment specific space management logic which dictates
the (different) locations where the two writes physically end up writing).
Of course if you try to update let's say only a 1kB portion of a 16kB LOB
chunk, then the chunk has to be read from disk first.

On Fri, Dec 7, 2012 at 1:19 PM, Jonathan Lewis

> ----- Original Message -----
> From: "Saibabu Devabhaktuni" <saibabu_d@xxxxxxxxx>
> | Jonathan,
> | I couldn't reproduce the scenario of reading the same block with "db file
> sequential read" waitevent and immediately followed by "direct path read"
> waitevent.
> I thought I did it last night with:
>     flashback logging on
>     lob segment in ASSM tablespace
>     switch log file
>     flush buffer cache
>     insert lob


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