Re: Vaccuum allows read access?

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > In the current sources, analyze allows read-access.  I don't think
> > vacuum allows any other access because the rows are moving in the file.
>
> VACUUM *must* have exclusive lock.
>
> ANALYZE actually is only a reader (AccessShareLock) and does not lock
> out either reading or writing in current sources.

    Some related issue though.

    On  the phone we discussed about the btree splitpage problems
    and  you  said  that  the  current  btree  implementation  is
    optimized  for  concurrent read and insert access, not so for
    concurrent deletes.

    This might get to be a problem with the  overwriting  storage
    manager.   If  it  wants to reuse space of outdated tuples in
    the main heap, it needs to delete index tuples as well. Isn't
    that in conflict with the btree design?


Jan

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