Hi, how records are managed is storage dependent. So LOCAL keep the RID to offsets ad then store pointers to the real position on disk. By using a middle structure allow to move records during defrag without changing RID.
This is not index, but an indirect lookup (2 lookups) Lvc@ On 23 February 2014 00:16, Steve <[email protected]> wrote: > Thanks Luca, > > So if it is a physical offset what happens if the record has to be > physically moved? i.e. say we have record n at offset 100 and record n+1 > at offset 200. If we update record n and add a property that is 101 bytes > long don't we have to move the record since it won't fit without > overwriting part of record n+1? Or during a defrag operation I would > assume many records get moved around? > > Perhaps I am not making a distinction between a record and an object. Is > it that a logical object can be represented by many records in it's > lifecycle? > > If a move does happen then wouldn't this mean the entire database has to > be scanned to find any references to that physical cluster position? Or is > there a table of back-references stored somewhere? > > > On 23/02/14 09:07, Luca Garulli wrote: > > It's the offset inside a cluster, so it never can change during the record > lifecycle up to the delete. And with plocal the RID is not recycled. > > Lvc@ > > > > On 22 February 2014 02:26, Steve <[email protected]> wrote: > >> Is it actual offset of the record in the cluster or is it and index in a >> lookup table? If it is literal wouldn't that mean if a record has to be >> moved (perhaps due to growing in size) that all references to it have to >> be found and updated? >> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "OrientDB" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- > > --- > You received this message because you are subscribed to the Google Groups > "OrientDB" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- > > --- > You received this message because you are subscribed to the Google Groups > "OrientDB" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
