Currently we read and write 64KB at a time in the nio libraries. As a
single byte buffer per event loop thread does not consume much memory,
there is little reason to not increase it further. This commit increases
the buffer to 256KB but still limits a single write to 64KB. The write
limit could be increased, but too high of a write limit will lead to
copying more data (if all the data is not flushed and needs to be copied
on the next call). This is something to explore in the future.
Closing a channel using TLS/SSL requires reading and writing a
CLOSE_NOTIFY message (for pre-1.3 TLS versions). Many implementations do
not actually send the CLOSE_NOTIFY message, which means we are depending
on the TCP close from the other side to ensure channels are closed. In
case there is an issue with this, we need a timeout. This commit adds a
timeout to the channel close process for TLS secured channels.
As part of this change, we need a timer service. We could use the
generic Elasticsearch timeout threadpool. However, it would be nice to
have a local to the nio event loop timer service dedicated to network needs. In
the future this service could support read timeouts, connect timeouts,
request timeouts, etc. This commit adds a basic priority queue backed
service. Since our timeout volume (channel closes) is very low, this
should be fine. However, this can be updated to something more efficient
in the future if needed (timer wheel). Everything being local to the event loop
thread makes the logic simple as no locking or synchronization is necessary.
`PageCacheRecycler` is the class that creates and holds pages of arrays
for various uses. `BigArrays` is just one user of these pages. This
commit moves the constants that define the page sizes for the recycler
to be on the recycler class.
This is related to #27260. In Elasticsearch all of the messages that we
serialize to write to the network are composed of heap bytes. When you
read or write to a nio socket in java, the heap memory you passed down
must be copied to/from direct memory. The JVM internally does some
buffering of the direct memory, however it is essentially unbounded.
This commit introduces a simple mechanism of buffering and copying the
memory in transport-nio. Each network event loop is given a 64kb
DirectByteBuffer. When we go to read we use this buffer and copy the
data after the read. Additionally, when we go to write, we copy the data
to the direct memory before calling write. 64KB is chosen as this is the
default receive buffer size we use for transport-netty4
(NETTY_RECEIVE_PREDICTOR_SIZE).
Since we only have one buffer per thread, we could afford larger.
However, if we the buffer is large and not all of the data is flushed in
a write call, we will do excess copies. This is something we can
explore in the future.
This commit is related to #32517. It allows an "sni_server_name"
attribute on a DiscoveryNode to be propagated to the server using
the TLS SNI extentsion. Prior to this commit, this functionality
was only support for the netty transport. This commit adds this
functionality to the security nio transport.
This change cleans up "unused variable" warnings. There are several cases were we
most likely want to suppress the warnings (especially in the client documentation test
where the snippets contain many unused variables). In a lot of cases the unused
variables can just be deleted though.
This is related to #27260. It adds the SecurityNioTransport to the
security plugin. Additionally, it adds support for ip filtering. And it
randomly uses the nio transport in security integration tests.
Currently we set local addresses on the creation time of a NioChannel.
However, this may return null as the local address may not have been
set yet. An example is the local address has not been set on a client
channel as the connection process is not yet complete.
This PR modifies the getter to set the local field if it is currently null.
Currently, when we open a new channel, we pass it an
InboundChannelBuffer. The channel buffer is preallocated a single 16kb
page. However, there is no guarantee that this channel will be read from
anytime soon. Instead, this commit does not preallocate that page. That
page will be allocated when we receive a read event.
This is related to #28898. This PR implements pooling of bytes arrays
when reading from the wire in the http server transport. In order to do
this, we must integrate with netty reference counting. That manner in
which this PR implements this is making Pages in InboundChannelBuffer
reference counted. When we accessing the underlying page to pass to
netty, we retain the page. When netty releases its bytebuf, it releases
the underlying pages we have passed to it.
This is related to #27260. Currently when we queue a write with a
channel we set OP_WRITE and wait until the next selection loop to flush
the write. However, if the channel does not have a pending write, it
is probably ready to flush. This PR implements an optimistic flush logic
that will attempt this flush.
Tim Brooks
Christoph Büscher
Alpar Torok
Tanguy Leroux
Jason Tedor