Florent Guillaume wrote:
I know this has been raised several times in the past, but I'm not sure of all the details...


What layer of ZODB, if any, has a restriction that OIDs be 8-byte strings. Is it the persistence module? Or just FileStorage? Also is there a reason (performance, space?) for this restriction, and would anyone be interested in seeing it removed.

I'm asking because I'm planning a pretty complex storage layer, which would benefit from more complex OIDs (for instance bigger strings, or tuples of (str, int)).

ZODB imposes no limit on OID length.  The only restrictions on OIDS
imposed by ZODB is that:

- They are strings, and

- The string consisting of 8 null characters is reserved for the
  root database object.

Otherwise, OIDs are controlled by storages, which have complete control
over them.  ZODB and higher-level code sould never make any assumptions
about nor try to control OIDs, except in the case of the root object.

Many storages use 64-bit unsigned integers, serialized as 8-byte strings
for memory and space efficiency and to make allocation of new ids simple.

Jim

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