Moving BLOBs from BASICFILES to SECUREFILES
From: Chen Zhou <oracle.unknowns_at_gmail.com>
Date: Tue, 9 Feb 2016 14:10:46 -0800
Message-ID: <CAJUY3dStci5istbseO=GWAEpJaeQc6TBTHyvn88WYt=_jCibQw_at_mail.gmail.com>
Hi,
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.
Chen
Date: Tue, 9 Feb 2016 14:10:46 -0800
Message-ID: <CAJUY3dStci5istbseO=GWAEpJaeQc6TBTHyvn88WYt=_jCibQw_at_mail.gmail.com>
Hi,
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.
Chen
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Feb 09 2016 - 23:10:46 CET