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Undo segment in buffer cache

TapasDalaiJan 9 2016 — edited Jan 9 2016

Hi friends,

I have a strong doubt on below topic. here i am not talking about undo tablespace

1)how undo things works exactly.

2) like we have sharedpool, buffer cache, large pool etc exists in SGA, Do we have a specific buffer area that is reserved for undo segment and we call that this is undo area.

3) Like DB writter writes data into Data file and LGWR writes data into logfiles. so likewise which process  writes data into undo files in undo tablespace.

3) like, we can track each data block in  buffer cache by using v$bh table. likewise Can we track detail progress of undo blocks. form which view ??

4) when i looked into x$bh table for a particular block of a table  i found there are many columns referring undo related data and those columns start with CR_UBA_ can some body tell more about this

Your answer and effort would Appreciate.

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Locked on Feb 6 2016
Added on Jan 9 2016
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