Some tests, but in particular CodecTests, are slow because they test all
versions that ever existed even though they should only test supported
versions.
Today we throttle recoveries only for incoming recoveries. Nodes that have a lot
of primaries can get overloaded due to too many recoveries. To still keep that at bay
we limit the number of threads that are sending files to the target to overcome this problem.
The right solution here is to also throttle the outgoing recoveries that are today unbounded on
the master and don't start the recovery until we have enough resources on both source and target nodes.
The concurrency aspects of the recovery source also added a lot of complexity and additional threadpools
that are hard to configure. This commit removes the concurrent streamns notion completely and sends files
in the thread that drives the recovery simplifying the recovery code considerably.
Outgoing recoveries are not throttled on the master via a allocation decider.
We added this undocumented realtime setting as backup plan long ago
but to date we haven't had a situation where it was a problem. It's reducing
the number of filehandles in the NRT case dramatically and should always be enabled.
Today the logic to async - commit the translog is in every translog instance
itself. While the setting is a per index setting we manageing it per shard. This
polluts the translog code and can more easily be managed in IndexService.
Today we have two variants of translogs for indexing. We only recommend the buffered
one which also has a 20% advantage in indexing speed. This commit removes the option and defaults
to the buffered case. It also hard-wires the translog buffer to 8kb instead of 64kb. We used to
adjust that buffer based on if the shard is active or not, this code has also been removed and
instead we just keep an 8kb buffer arround.
This commit removes `index.translog.flush_threshold_ops` and `index.translog.disable_flush`
in favor of `index.translog.flush_threshold_size`. The number of operations is meaningless by itself and
can easily be turned into a size value with knowledge of the data. Disabling the flush is only useful in
tests and we can set the size value to a really high value. If users really need to do this they can
also apply a very high value like `1PB`.
Yannick Welsch
Adrien Grand
Simon Willnauer
Simon Willnauer
kwangsik
Robert Muir
Ryan Ernst
Jun Ohtani
Jim Ferenczi