Blobspace Logging

IBM Informix Dynamic Server Version 11.50.FC9 Software Serial Number AAA#B000000 I am looking for some clarification on Blobspace Logging. I find thus in man pages The database server logs blobspace data, but the data does not pass through either shared memory or the logical-log files on disk. The database server copies data stored in a blobspace directly from disk to tape. Records of modifications to the blobspace overhead pages (the free-map and bitmap pages) are the only blobspace data that reaches the logical log. not sure what this means The database server copies data stored in a blobspace directly from disk to tape when smart blob is update what is wriiten to the logical log ? any help please

Correct. Blobs in blobspaces are NOT LOGGED! When you "change" a blob, the engine merely writes a new copy of the blob on another set of blob pages and records the fact of the change to the locator structure column that is stored with the rest of the table's in-page data in the logical logs. Both copies continue to exist for rollback purposes until you perform your next archive at which point the engine will clean up the orphaned deleted blob pages. Smart blobs are written to the logical logs if the smartblob space they are stored in is a logged smartblob space. By default smartblob spaces are logged, but you can change their status to unlogged (normally this should only be done for temporary smartblob spaces). Art Art S. Kagel, Principal Consultant Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Sun, Sep 22, 2013 at 11:20 PM, KARL OLIVER <karl.oliver@maf.govt.nz>wrote: > IBM Informix Dynamic Server Version 11.50.FC9 Software Serial Number > AAA#B000000 > > I am looking for some clarification on Blobspace Logging. > I find thus in man pages > The database server logs blobspace data, but the data does not pass through > either shared memory or the logical-log files on disk. The database server > copies data stored in a blobspace directly from disk to tape. Records of > modifications to the blobspace overhead pages (the free-map and bitmap > pages) > are the only blobspace data that reaches the logical log. > > not sure what this means > > The database server copies data stored in a blobspace directly from disk to > tape > > when smart blob is update what is wriiten to the logical log ? > any help please > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --089e0160b82890ca6b04e705042b