• Levin Zimmermann's avatar
    bigfile/zodb: Make h format the default · 2bc0e789
    Levin Zimmermann authored
    If a user doesn't explicitly declare a ZBlk format, it can be assumed
    that this user wants to have the best ratio between consumed storage space
    and data access speed. Currently the best ratio between these two is
    provided by the new 'h' (heuristic) format. In case of small appends this
    format helps reducing storage space, and in any other case it just
    behaves like ZBlk0 [1]. Therefore this default ensures a fast access speed [2],
    but also avoids a massive data growth in case of many small appends [3].
    
    [1] An exception to this is: in its current implementation a block
    behaves like ZBlk1 (slow access) in case it isn't fully filled up yet.
    
    [2] As this was stated as a reason why ZBlk1 as a default format was
    reverted in nexedi/wendelin.core@0b68f178.
    
    [3] This was perhaps the reason why ZBlk1 was set to be the default format
    in nexedi/wendelin.core@9ae42085. The massive
    storage space consumption can already be a problem with few array to
    which regularly small data is appended to, as it can easily happen with
    Wendelin development instances.
    2bc0e789
file_zodb.py 34.1 KB