what is the purpose of sealed DDB

Sure thing!

For full background, a Dedupe Database has 3 tables:

• Primary - List of unique blocks
• Secondary - Number of references for each unique block
• Zero Ref - List of blocks that have no more jobs referencing it (which can therefore be deleted)

As jobs get written, the DDB is checked to see if the blocks are already known/stored, and references are added incrementally as needed.

A sealed DDB is still used for micro pruning by doing the micro pruning.  No NEW blocks/references are applied, but we do handle pruning still.

Now, if you didn’t have that DDB, pruning would not be able to decrement the references, nothing would get added to the ZeroRef table, and no micro pruning would occur.  You’d have to wait for ALLLLLL of the jobs to age off, then the whole store would age off (library data and all).

Let me know if that clarifies!