Glauber Costa 10c8ca6ace priority manager: separate streaming reads from writes ...

Streaming has currently one class, that can be used to contain the read
operations being generated by the streaming process. Those reads come from two
places:

- checksums (if doing repair)
- reading mutations to be sent over the wire.

Depending on the amount of data we're dealing with, that can generate a
significant chunk of data, with seconds worth of backlog, and if we need to
have the incoming writes intertwined with those reads, those can take a long
time.

Even if one node is only acting as a receiver, it may still read a lot for the
checksums - if we're talking about repairs, those are coming from the
checksums.

However, in more complicated failure scenarios, it is not hard to imagine a
node that will be both sending and receiving a lot of data.

The best way to guarantee progress on both fronts, is to put both kinds of
operations into different classes.

This patch introduces a new write class, and rename the old read class so it
can have a more meaningful name.

Signed-off-by: Glauber Costa <glauber@scylladb.com>

2016-03-23 09:12:59 -04:00

7.4 KiB

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