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Accumulo, mail # user - Which key/value pairs are held in memory?


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Re: Which key/value pairs are held in memory?
Josh Elser 2012-11-01, 11:55
I believe only the tablet server which currently hosts the tablet which
contains the key which you inserted will contain that pair in the
in-memory map (memtable).

The pair hitting multiple loggers ensures that the data is not lost, but
since a tablet is only ever hosted by one server at a time, the k/v pair
is not placed into multiple servers' memory map.

On 11/1/12 7:34 AM, Kristopher Kane wrote:
> In the manual, it is stated that a write is sent to multiple loggers,
> written to the wa log and key/value pairs stored in a memtable and an
> index.
>
> Since the write hits several servers for resiliency, does each of the
> servers that receives the write place the same data in memory or do
> they each place a different portion in memory such that a read could
> span multiple servers for a performance gain?
>
> Thanks,
>
> -Kris