From: Chen Zhou <>
Date: Tue, 9 Feb 2016 14:10:46 -0800
Message-ID: <>

We have this table with BLOBs, which has high "enq:HW- contention" from time to time.
We already have event "44951 TRACE NAME CONTEXT FOREVER, LEVEL 1024" set. The only option I can think of is to move this BLOB from BASICFILE to SECUREFILE.
There has been discussion of doing this by using dbms_redefinition here, it seems to be a great tool that allows changing BLOB online. This is a very important production database, will there be significant performance impact using this tool? If so, we may just schedule a maintenance time.
How long should we expect to redefine 300GB BLOBs? A few hours or a few days? Can it end up hanging?
Can I take the opportunity to move the BLOB to another tablespace during this redefinition process?
Thank you for your information.
Received on Tue Feb 09 2016 - 23:10:46 CET

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